P.71 P.72
CARDIAC DAMAGE AND BLOOD PRESSURE VARIABILITY REDUCTION AFTER CHARACTERIZATION OF AT! RECEPTORS ON MITOCHONDRIAL MEMBRANES ANTIHYPERTENSIVE DRUG THERAPY WITH IRBESARTAN. IN RAT LIVER
V.Rizzo, S.Villatico Campbell, F.Di Maio, F.Petretto, *D .Tallarico, V.Marigliano. I Clinica Seccia TM Lograno MD*, Vulpis V and Pirrelli A Medica *VI Clinica Medica, "La Sapienza" University of Rome, Via del Policlinico 155, Chair of Internal Medicine, *Department of Pharmaco-Biology, Policlinico, Univefllity of Rome, Italy. Bari, Italy
Left ventricular hypertrophy (LVH) regression is a common evidence of long-term The different responses to angiotensin II (ang II) are related to the multiple sites of actions in antihypertensive drug therapy (ADT). To evaluate LVH regression and blood pressure the cell. Although the major regulating mechanism is mediated by the signal transduction at (BP) variability reduction after ADT , 40 mild-to-moderate hypertensive subjects (22 M the level of plasma membrane, accumulating evidence shows ang U-binding sites in subcellular compartments. and 18 F, mean age 51.32 ± 8.86 yrs.) were enrolled if they had left ventricular mass The aim of the present study was to investigate whether binding sites for ang II are located, (LVM) index> 125 gfm2 (Penn Convention). They were submitted to a monotherapy other than on plasma membranes, also on mitochondrial membranes. with lrbesartan single daily dose (I) ; BP variability reduction, LVM index changes were Investigation was made on mitochondria isolated from the hepatic tissue of male Wistar rats evaluated by ambulatory blood pressure monitoring (ABPM) and 20 M-mode (n = 15; body weight = 150-200g). After isolation of mitochondria from the hepatic tissue, echocardiography at baseline (TO) , after 8 (T1) and after 16 weeks of therapy (T2). The competition binding assays were performed to characterize ATl receptofll. results are shown in the table. [3H] DUP 753 (NenDupont, 61 Ci/mmol) was used as selective ligand for AT! receplolll. Specific binding of [3H] DUP 753 to ATl receptofll was calculated as binding which was TO T1 T2 dispaced by cold DUP 753. It was saturable, revefllible and represented about 80% of the 24 h OS SBP 18.23 + 3.21 16.34 + 4.11 14.45 + 4 01 total binding at 6 nM ligand concentration. Scatehard analysis of [3H]DUP 753 binding to 24 h OS DBP 13.45 + 2.23 11.68 + 3.23 10.34 + 2.77 isolated mitochondria revealed a linear plot suggesting a single class of binding sites. The maximum number of binding sites (Bmax) and the dissociation constant (Kd) were calculated Daytime OS SBP 15.34 + 3.11 14.49 ± 2.98 13.64 + 3.33 using the computerized program "Ligand": Kd = 62 ± 6 nM; Bmax = 5431 ± 670 fmol . mg Daytime OS DBP 13.36 + 3.44 12.99 ± 3.37 12.66 + 1.97 mitochondrial proteins_, (mean value± SE). Nighttime OS SBP 11 .65± 4.08 10.98 + 4.12 10.34 + 2.02 These results show the presence of ATl receptolll on mitochondrial membranes in rat liver, Niqhttime OS DBP 9.56 + 3.66 8.96 + 3.23 8.54 + 2.31 thus suggesting further sites of action of ang II in the cell, other than plasma membranes. LVMI 138.89 + 5.61 124.48 ± 5.67* 119.45±6.11' It is well known that ang II plays a relevant role for liver metabolism, and in particular fur *p<0.05 glycogenolysis and gluconeogenesis; the detection of ATl receptors on mitochondrial membranes suggests a peculiar effect of ang II on the biochemical pathways occurring in I obtained a statistically significant BP variability reduction and LVH regression , showing mitochondria. Moreover, the findings of this study, together with the recent evidence of the efficacy in the reduction of the long-teFm adverse consequences of BP chronic literature showing nuclear ang 11-binding sites in rat liver, might support the direct overload. intracellular action of ang II and provide evidence fur the controlling intracrine mechanism of angii.
P.73 P.74 .Y_ALSARTAN ANTIHYPERTENSIVE LONGTERM liSE BAROREFLEX SENSITIVITY IN ESSENTIAL HYPERTENSION TREATED :Q.Y ALUA TION (THE VALUE TRIAL) WITH TRANDOLAPRIL AND DILTHIAZEM IN COMBINATION. B. Fiser I ,J. Siegelova, J. Dusek, Z. Placheta, E. Savin2, J.P. Martineaud2 ·Dept. od S Julius, HR Brunner, L Hansson, SE Kjeldsen*, JH Laragh, GT Functional Diagnostics and Rehabilitation, I Dept. ofPhysiology, Masaryk University, Mcinnes, MA Weber, A Zanchetti for the VALUE Trial Group. Bmo, 2Faculty of Medicine Lariboisiere, Paris, France *Department of Cardiology, Ullevaal Hospital, Oslo, Norway. The baroreflex (heart rate) sensitivity (BRS) in patients with essential hypertension is generally low. A slight increase ofBRS but not normalization of values was observed Diuretics, beta-blockers and calcium channel blockers (CCBs) after the verapamil or enalapril placebo controlled treatment (a monotherapy). have proven, though hitherto suboptimal, effects on CV The aim of the present study was the evaluation ofBRS after the treatment with mortality and morbidity in hypertension. High renin and trandolapril and dilthiazem in combination. Eighteen patients with mild essential angiotensin II (AU) causes cardiovascular (CV) damage. hypertension were examined after 2 weeks of the wash-out placebo period (EH P) and Specific and selective blockade of Ail mediated effects through after 3 months of the combined treatment with trandolapril (2 mg, in one morning the A Tl-receptor may therefore offer improved CV protection dose) and dilthiazem retard (90 mg, twice a day, EH TV). The results were compared in hypertension. The VALUE Trial is therefore testing the with I 0 age and sex matched normotensive controls (C). BRS was determined by hypothesis that in a group of high risk patients, for the same spectral analysis of spontaneous fluctuations of systolic blood pressure (SBP) and level of BP control, the ATl-receptor blocker valsartan reduces cardiac intervals (Finapres, 5-min record, metronome controlled breathing). The Ethics Committee of the Masaryk University Teaching Hospital approved the study. cardiac morbidity and mortality by 15 % compared to the CCB The results (mean±SD) of SBP, diastolic pressure (DBP), heart rate (HR) and BRS are amlodipine. The trial is a double-blind, randomized, in 31 given in the following table: countries, prospective comparison of valsartan 80 and 160 mg SBP mrnHg DBPmmHg HRb.p.m. BRS mms/mmHg (± hydrochlorothiazide, HCTZ), once daily with amlodipine 5 and c 121 ±6 82±5 75±7 7.8±3 .8 10 mg (± HCTZ) once daily. 14,400 previously untreated (range EHP 146±10**++ 105±7**++ 80±7* 4.9±2.7*+ SBP 160-210 mmHg, DBP 95-115 mmHg) or treated EHTB 128±8 82±9 76± 10 8.2±3 .4 hypertensives, <:50 yrs with high risk of CV events (i.e. one or (EH P versus EH TV*, versus C+, *+ p<0.05, **++ p S19 P.75 P.76 MINIMUM FOREARM VASCULAR RESISTANCE IN ESSENTIAL THE ROLE OF TIGHT BINDING IN THE INSURMOUNTABLE EFFECT OF HYPERTENSION AFTER ANTIHYPERTENSIVE THERAPY. NON-PEPTIDE ANGIOTENSIN II ANTAGONISTS 1J. Dusek, 1J. Siegelova, 2B. Fiser,3E. Savin, ' J.P. Martineaud, 1Dept. od Functional F.L.P. Fierens P.M.L. Vanderheyden, J-P. De Backer and G. Vauquelin Diagnostics and Rehabilitation, 2Dept. of Physiology, Masaryk University, Bmo, Department of Protein Chemistry, Free University of Brussels (VUB), Paardenstraat 'Faculty of Medicine Lariboisiere, Paris, France 65, B-1640 Sint-Genesius Rode, Belgium Minimum forearm vascular resistance (FVR,.;,) is increased in essentiai hypertension and decreases during the antihypertensive therapy. The aim of the present study was to In this study we investigated in more detail the surmountable and insurmountable analyze the relationship between the blood pressure (BP) decrease and(FVR,.;,) behaviour of the non-peptide angiotensin IT type l antagonists candesartan, irbesartan, decrease due to a different antihypertensive therapy. Patients (all men, aged 48±5 losartan and EXP3174. Angiotensin IT increases inositol phosphate accumulation with years, 18 1±5cm, 86±8kg) with mild to moderate essential hypertension were examined an EC 50 of3.4 ± 0.7 nM in CHO-KI cells expressing the cloned human angiotensin II after the placebo therapy and 3 months after the therapy with Ca antagonists veraparnil AT1 receptor. (5 ntin incubation at 3TC, 10 mM LiCI) Coincubation of the (240 mg slow releasing, one morning dose, n=IO, EH V), nitrendipine (20 mg per day, antagonists with angiotensin II produced parallel rightward shifts of the two times per day, n= IO, EH N), dilthiazem (90 mg retard, twice a day, n= IO, EH D), concentration-response curves without affecting the maximal response, wich is in line and with ACE inhibitor (enalapril, 13 .3±2.1mg, onece per day, n=IO, EH E). (FVR..in with a competitive mode of action. was examined using the occlusion plethysmography (occlusion 300 mmHg, 5min). The In contrast, for certain of the antagonists preincubation of 30 min results in an Ethics Committee of the Masaryk University Teaching Hospital approved the study. additional depression of the maximal response. Our data suggest that this The results (expressed as a mean±SD) of FVR,.;, (in mmHg/ ml per 100 ml per min) insurmountable behaviour is related to their ability to devide the AT 1 receptors into and mean BP (MAP, mmHg) in all studied groups (placebo therapy), decrease of two populations. The antagonist-receptor complexes are able to adopt a fast MAP (dP,%), decrease ofFVRmm (dR,%) and ratio dP/dR due to the therapy are given reversible/surmountable and a tight binding/insurmountable state. Wbereas the in Table. equilibrium between both states is dependent on the nature of the antagonist, it is EHV EHN EHD EHE unaffected by prolongation of the antagonist preincubation. Furthermore this FVRmin 4.7±1.6 6.6±1.5 4.1±1.5 4.6±1.5 equilibrium is constant for candesartan and EXP3 I 74, when the angiotensin II MAP 118.8±7.1 115.7±5.6 121.1±9.1 109.7±8.7 incubation time is varied between I and 5 min. dP *12.4±7.1 *13.7±6.5 *17.5±7.9 *10.4±6.9 Whilst the insurmountable effect of the antagonists is traditionally presented by dR *32.6±18.6 *36.2±7.6 *44.5±15.2 *11 .1±15.3 angiotensin II dose-response curves, it can be better quantified measuring the agonist dR/dP 2.6±1.4 2.6±0.5 2.5±0.9 4.1±1.6 responses after preincubation with increasing antagonist concentrations. (Statistical significance versus placebo p<0.05, Wilcoxon.) These inhibitioncurves are biphasic and allow the quantification of the proportion in From our results we can conclude that the antihypertensive therapy with Ca the tight binding/insurmountable state and are ;. 95 % for candesartan, 70 % for antagonists and ACE inhibitor decreased the minimum forearm vascular resistance and EXP3174, 30% for irbesartan and is not detectable for losartan. no differences among these drugs were observed. Supported by TG A MZ CR 4313-3. P.77 P.78 ' IN VITRO' PHARMACOLOGY OF ANGIOTENSIN II TYPE I ANTAGONISTS SAFETY AND TOLERABILITY OF CANDESARTAN CILEXETIL INPATIENTS ON CHO-KI CELLS EXPRESSING HUMAN AT1 RECEPTORS. WITH CHRONIC, STABLE ANGINA PECTORIS P.M.L. Vanderheyden, F.L.P. Fierens, J.P. De Backer, and G.Vauquelin 3 1 2 Department of Protein Chemistry, Free University of Brussels (VUB), Paardenstraat R Wol f', B Behrens' , SG Magin Herz-Kreislauf-Klinik, Bad Bevensen, Medialog 65, B-1640 Sint-GenesiusRode, Belgium. GmbH, Detmold, ' Takeda Euro R&D Centre GmbH, Frankfurt, Germany We have investigated the pharmacological properties of the non-peptide angiotensin Candesartan cilexetil, a long-acting angiotensin II type 1 receptor antagonist, II type I antagonists candesartan, irbesartan and losaratan as well as its active combines antihypertensive efficacy with placebo-like tolerability in patients with metabolite EXP3174 on a CHO-AT1 cell line stable expressing the human AT1 essential hypertension. Candesartan cilexetil is also well tolerated in patients with receptors. Angiotensin II causes a fast and transient rise of intracellular calcium congestive heart failure, and improves symptoms and exercise tolerance. concentration and, in the presence of 10 mM LiCI, a sustained increase in the This multicentre study conducted at II sites in Germany examined the safety and production of inositol phosphates (IP), with half maximal stimulation at 3 nM. The tolerability of candesartan cilexetil added to existing antianginal drug therapy in tested antagonists completely inhibit the angiotensin II (0.1 [.1M) induced IP patients with coronary heart disease (CHD) and borderline to moderate essential accumulation, the cell-surface [3H]-angiotensin binding as well as [3H]-candesartan hypertension (sitting diastolic blood pressure 2:90 mmHg and :5109 mmHg). binding to intact cells, with the potency order candesartan > EXP3174 > irbesartan > CHD was manifest as chronic, stable, exercise-inducible angina pectoris. losartan. Furthermore, pre-incubation with candesartan decreases the maximal 144 patients entered a 4-week placebo run-in period and 134 were randomised to angiotensin IT induced IP accumulation up to 94 % and, concomitantly, decreases the double-blind add-on treatment with candesartan cilexetil 8 mg o.d. (n=68) or placebo maximal binding capacity of the cell surface receptors. These effects are half-maximal (n=66) for 12 weeks. Concomitant anti-ischaemic medications included nitrates for 0.6 nM candesartan. On the other hand, losartan causes a parallel rightward shift (57%), P-blockers (47%), calcium channel blockers (39%) and antithrombotics (13%), of the angiotensin II dose response curves and does not affect the maximal binding and were maintained as usual throughout the study. capacity. The antagonists EXP3174 and irbesartan show a mixed-type behaviour in A low proportion of patients experienced adverse events (AEs) with the multiple drug functional and in binding studies. The reversal of the inhibitory effect is much slower regimen. The incidence of AEs was similar with candesartan cilexetil and placebo for candesartan as compared with EXP3 17 4 and irbesartan and it is almost (24.2% and 23.5%, respectively, both n=16). The relationship of AEs to study instantaneous for losartan. In agreement the [3H]-candesartan binding to intact cells, medication, and their frequency and intensity (all except I were rated as mild or slowly dissociates after addition of 10 JiM losartan (tln= l30 min). Finally the moderate) was similar with candesartan cilexetil and placebo. Overall, the profile of insurmountable inhibition of candesartan is attenuated in the presence of a high AEs did not differ relevantly between treatment groups. concentration of losartan. Our results suggest that the insurmountable nature of There \vas a positive trend in favour of candesartan cilexetil for reduction in mean angiotensin II type I antagonists in functional studies is related to their long-lasting number of angina pectoris attacks per week from baseline to endpoint (- 1.7 with inhibition and that an allosteric modulation is rather unlikely. candesartan cilexetil vs - 1.2 with placebo) and for reduction in mean weekly use of short-acting nitrates (- 1.5 vs - 1.3 times, respectively). In conclusion, candesartan cilexetil exhibits a similar tolerability profile to placebo when added to standard anti-anginal medication in patients with CHD. S20 P.79 P.80 ABSENCE OF PHARMACOKINETIC INTERACTION BETWEEN DIGOXIN A,'ill PHARMACOKINETICS, HAEMODYNA,MICS AND SAFETY OF CANDESARTAN CANDESARTAN CILEXETIL IN HEALTHY VOLUNTEERS CILEXETIL IN HYPERTENSIVE PATIENTS UNDERGOING HAEMODIAL YSIS H-J Arens, M George. Takeda Euro R&D Centre GmbH, Frankfurt, Germany & London, UK; M Pfister, FJ Frey, DE Uehlinger. Division of Nephrology and Hypertension, Dept. of PNM van Heiningen, Phanna Bio-Research International BV, Zuidlaren, The Netherlands Medicine, University of Berne, CH-3010 Berne, Switzerland Candesartan cilexetil, a novel long-acting angiotensin ll type 1 (ATI) receptor antagonist, has proven antihypertensive efficacy. It is also potentially beneficial in patients with congestive The new antihypertensive agent candesartan cilexetil, a long-acting angiotensin II type 1 heart failure (CHF). This randomised, open-label, multiple-dose, 3-way crossover study (AT1) receptor antagonist, is completely hydrolysed to the active moiety candesartan during evaluated the effects of candesartan cilexetil on the steady-state pharmacokinetics of digoxin gastrointestinal absorption. Candesartan cilexetil is reported to be well tolerated in patients and vice versa in healthy volunteers. 12 subjects (6 male & 6 female, aged 19-34years, and bodyweight within± 15% of normal with impaired renal function and to have no adverse systemic or renal haemodynamic effects. We examined the tolerability profile and pharmacokinetics of candesartan following oral range) received candesartan cilexetil16 mg orally once-daily (od), digoxin 0.25 mgorally od (on day 1: 0.5 mg loading dose [morning], 0.25 mg [evening]), or the two in combination. administration of candesartan cilexetil 8 mg o.d. for 5 days in hypertensive patients (n=8, male, aged 38-75 years; diastolic BP ;?:90 mmHg and mmHg;) with severe renal Each drug was administered for 9 days, with a washout of at least 7 days between treatments. dysfunction undergoing regular haemodialysis. The oral clearance of candesartan decreased Maximum plasma concentration (Cmax) and area under the plasma concentration. time curve between day 1 and day 5, as indicated by Rkin (ratio of AUCtau day 5/AUCinfday 1) of at steady-state (AUC) for both drugs were not significantly different between combined 1.34 and Rae (ratio of AUCtau day 5/AUCtau day 1) of\.52 (Table and Figure). administration and monotherapy. Mean serum digoxin concentration {n=12) Mean serum candesartan concentration (n=12) Mean serum candesartan concentration -candesartancilexetil -digoxin Mean (±SD) Day 1 Day 5 ------.candesartan cilexetil +digoxin 120 -candesartancilexetil+digoxin ::1 .;. 1.01 c,= (ng/ml) 86.5 (26.4) 128 (35.7) a Tm.,(h) 3.5 (1.2) 3.4 (0.7) --oay s T,(h) 7.3 (2.3) 9.9 (3.2) --oay 1 AUC;nr (ng·h/ml) 1025 (482) 1805 (919) I I AUCtau (ng·h/ml) 1369 (587) 20 Rkin 1.34 (0.36) 1.52 (0.44) M T M T 0 158192 196 200 204 208 212 216 0 168192 Hl6 200 204 208 212 216 Time (h) Time (h) Hours post-dose No gender-specific differences were apparent when Cmax and AUC were corrected for (dose Candesartan was highly bound to serum proteins and was minimally extracted by per) bodyv;eight. No serious or severe adverse events (AEs) were observed. Female subjects haemodialysis. There were no serious adverse events in any patient. 5 patients reported 8 reported the majority of AEs. There was no change in the incidence and profile of AEs for adverse events; apart from one case of headache of severe intensity, all adverse events were combination vs nonotherapy. Candesartan cilexetil and digoxin show no significant of mild to moderate intensity. In conclusion, candesartan cilxetil is well tolerated and phannacokinetic interaction and are well tolerated when administered concomitantly. efficacious in patients with severe renal impairment; moreover, its pharmacokinetics are unlikely to be altered by haemodialysis to a clinically relevant extent. P.81 P.82 RENIN- ANGIOTENSIN- ALDOSTERONE SYSTEM'S ACTIVITY CHANGES IN CONGESTIVE HEART FAILURE NYHA II-IV PATIENTS STUDIES ON PRE- AND POST JUNCTIONAL ANGIOTENSIN RECEPTORS IN ON THE 1-ST AND 28-TH DAY OF TREATMENT. RAT MESENTERIC ARTERIES I.G.Fomina, Professor, S.A.Dovgolis, E.E.Kajarskaya, M.A.Uiibisheva. Moscow Medical Academy, Moscow, Russia James Ziogas and Kirstan Vessey. Department of Phannacology, University of Melbourne, Parkville, Victoria 3052, Australia. To reveal the neurohormonal mechanisms of improvement in coronary artery disease patients with Vasoconstrictor responses to angiotensin II (Ang II) in the rat hydronephrotic kidney congestive heart failure NYHA II-IV we studied renin, aldosterone and angiotensin II levels on the 1" have been reported to be sensitive to inhibition by both the AT! receptor antagonist and 28" day of treatment in 28 patients (14/14 male/female, 60± 10 years). 14 patients had the losartan and the AT2 receptor antagonist PD 123319 (Hayashi eta!., 1993 Am J history of previous myocardial infarction, 5 -suffered ..th angina pectoris, 13 - with atrial fibrillation Physic! 265: F881). Similarly, losartan and PD 123319 can each inhibit the prejunctional enhancement of noradrenaline release by Ang II in the rat tail artery (Cox and 23 -with arterial hypertension. 12 congestive heart failure NYHA II patients, 11 congestive heart et a/1995 Br J Phannacolll4: 1057). Therefore, the aim of the present study was to failure NYHA Ill patients and 5 congestive heart failure NYHA IV patients were admitted to the hospital mvest1gate the effects oflosartan and PD 123319 on the pre- and postjunctional effects because of their worsening and treated with aspirin, angiotensin II receptor antagonist valsartan and of Ang II in the rat mesenteric artery. The postjunctional vasoconstrictor responses to digoxin and/or fusemide, if necessary. Ang II were investigated in rat isolated mesenteric artery rings setup under an initial We found initial lowered renin level, increased aldosterone level and normal angiotensin II level in all tension of 0.3 g in a myograph. In five control arteries -Ang II elicited concentration congestive heart failure NYHA II-IV patients. dependent contractions with a pEC50 = 7.4 ± 0.3 and a maximum increase in tension All congestive heart failure NYHA II patients clinically improved after 4 weeks' treatment with of0.24 ± 0.1 g atO.l 11M· These contractions were competitively inhibited by 30 nM losartan (pEC = 6.3 ± 0.2, n = 6) but not significantly altered by 1 j.tM significant renin level increment to normal values (p=0.029) in 28 days. Aldosterone level appeared 50 PD 123319. Following treatment with NOLA (100 !1M) and indomethacin (3 j.tM), to decrease (p=0.097) but not to normal values. Angiotensin II level was found to change the constrictor responses to Ang II were significantly enhanced with a insignificantly. pEC50 = 7.9 ± 0.2 and a maximum of 0.45 ± 0.08 g (n = 6). These enhanced 4 weeks' treatment in congestive heart failure NYHA Ill patients resulted in significant aldosterone constrictor responses were again competitively inhibited by 30 nM losartan level decrement but not to normal values (p=0.030). Renin and angiotensin II levels were found to (pEC50 = 6.9 ± 0.3, n = 5) but unaltered by I !1M PD 123319. The prejunctional change insignificantly. All except 2 of these patients clinically improved in 28 days. effects of Ang II were determined as the enhancement of excitatory junction potentials (EJPs) measured using conventional intracellular recording techniques. Stimulation Only 3 congestive heart failure NYHA patients clinically improved after 4 weeks' treatment. Renin IV with 10 pulses at 0.9 Hz (5 - 20 V, 0.1 - 0.2 msec pulse width) evoked EJPs which level turned out to increase significantly to normal values (p=0.073). Angiotensin and aldosterone II were abolished by tetrodotoxin (0.1 j.tM), guanethidine (30 !1M) and levels were found to change insignificantly. ATP (3 !1M) indicating they were evoked by ATP released from sympathetic nerves. Conclusion. 1) Symptoms worsening in congestive heart failure NYHA II-IV patients appeared to be Ang II (0.1 - 300 nM) enhanced the purinergic EJPs in a concentration dependent associated with initially decreased renin level, increased aldosterone level and normal angiotensin II manner with a maximum increase in EJP amplitude of 44.6 ± 9.2 % (n=6) with 3 nM level. 2) Clinical improvement in congestive heart failure NYHA II patients was found to be Ang II. The enhancement of EJP amplitude by 3 nM Ang II was reduced to accompanied with significant renin increment and aldosterone decrement. 3) Amelioration in 7. I ± 2.4 % (n = 5) in the presence of 30 nM losartan but was not significantly affected by 100 PD 123319. These findings suggest that both the Ang II evoked congestive heart failure NYHA Ill patients might be connected with aldosterone level lowering. 4) 28 nM vasoconstriction and enhancement of purinergic EJPs in the rat mesenteric artery are days treatment in congestive heart failure NYHA IV patients turned out to be resulted in renin level mediated through the AT1 receptor. increasing. S21 P.83 P.84 Decreased vascular stiffness with Valsartan - an COULD ANGIOfENSIN IT TYPE I RECEPTOR ANTAGONISTS (ARATI) additional beneficial effect in hypertension BETIER PREVENT S1ROKE THAN ANGIOTENSIN II CONVERTING ENZYME INHIBITORS (ACEI) ? Azra Mahmud and John Feely, Department of Pharmacology & Therapeutics, Trinity Centre for Health Sciences, A. Fournier', JM. Achard', H Mazouz', A Pruna', C Hottelart', A. Rosa', L. Fernandez', M St. James's Hospital, Dublin 8, Ireland. Andrejack'.' CHU Amiens, France; 'Yale University, USA. Purpose of the Study: Early wave reflection is a marker of increased vascular stiffness In contrast with the expected results, the Captopril Prevention Project study has found which contributes to the development of hypertension and left ventricular hypertrophy. that the relative risk of stroke was greater by 25% in patients treated with ACEI than in Drugs that reduce early wave retlection, and hence reduce pulsatile load on the heart in patients receiving the conventionnal diuretics± betablockers regimen (Hanson et al, ISH Amsterdam, june 98). This difference persisted after adjustement for the initial addition to lowering peripheral resistance, have a greater potential in reversing the target differences of blood pressure levels between the groups after randomisation. This does organ damage in hypertension e.g. ACE inhibitors. However, the effect of angiotensin II not mean that ACEI would worsen the risk of stroke when compared to a placebo, receptor blockade on early wave reflection has not been studied. since a potent protective effect of diuretics and betablockers on the relative risk of Methods: We studied 12 patients, 7 female (mean age ±SD;56±8 years) with stroke has long been demonstrated. Nonetheless, these results suggest that for a uncontrolled hypertension on more than three antihypertensive including an ACE similar blood pressure lowering effect, conventionnal therapy is more effective than inhibitor; at baseline, 2 hours and 2 weeks after the oral administration of 80 mg of ACEI to prevent stroke. This finding, in discrepancy with the current prevailing valsartan. All haemodynamic measurements were made in the supine position after a rest opinion that ACEI have emerged as the most effective preventive treaunent to reduce of 15 minutes. Blood pressure was measured with the cuff sphygmomanometer and the cardiovascular morbidity, is regarded as surprising by the investigators. However, a number of animal experimental data may help to envisage the complete inhibition of radial artery pulse wave form was obtained by applantation tonometry using the angiotensin IT formation as a two-edged sword, because of the multiplicity of its Sphygmocor ® which generates the aortic pressure wave from the radial pressure wave at receptors mediating different, and even opposite effects. In a series of experimental the wrist and provides central systolic and diastolic blood pressures as well as studies in mammals, the group of Fernandez has provided a bundle of observations augmentation pressure (AP mmHg) in the aorta - an index of early wave reflection. suggesting that angiotensin II contributes to early reperfusion following acute Results were expressed as mean ±SD. Statistical analysis was done with the Student t ischemia by enabling the recruiunent of preexisting collateral vascularisation, an effect test. *P P.85 P.86 BENEFTI1AL EFFECI'S OF DIFFERENT ACE INlllBITORS ON INSULIN Losartan In The Correction Of Hypertensive Cardiac SENSITIVITY IN PATIENI'S WI1H ESSENTIAL HYPERTENSION Remodelling And Sympatovagal Balance E. V.Shlyachto, MD, prof, A.O.Conrady, MD. Lj.Bojovic. D.Micic, V.Stojanov D. V. Zaharov,MD, 0. G.Rudomanov MD Institute of pharmacology, Shoo! of medicine, Kragujevac St.Petersburg Pavlov Medical University, Sf-Petersburg. Russia The aim of the study was to evaluate the influence of losartan on left ventricular mass The aim of the current study was to evaluate a possible influence of either index (L VMI) and diastolic function and parameters of heart rate variability (HRV) in cilazapril or ramipril on paripherial insulin sensitivity in patients with mild-to· patients with essential hypertension (EH). moderate essential hypertension before and after the treatment with ACE We examined 21 patient with EH, middle age 45,7±1,9 years. LVMI and diastolic inhibitors for 3 months. Monotherapy with either cilazapril or ramipril was started function was measured by echocadiography. The low frequency (LF) and high after a two-week wash out period. We investigated 24 patients on cilazapril and 15 frequency (HF) components of power spectral analysis of 512 RR-intervals were patients on ramipril. Insulin sensitivity (Si) and glucose effectivness (Sg) were calculated. Patients were treated with losartan potassium 50 mg once daily for 6 assessed by a minimal model test using frequently sampled intravenous glucose months. tolerance test in 0 and 12 week of the treatment. Insulin sensitivity wa!. Losartan induced significant reduction of blood pressure from 166,2±1,4/104,1±1,1 significantly increased after 3 months with cilazapril (Si: 1.70 ± 1.29 vs. 2.65 ± 1.76 to 137, 1±2,3/86,9±1,4 mm Hg (p S22 P.87 P.88 INCREASE OF BLOOD FLOW VELOCITY IN THE VERTEBRAL AND AT, ANTAGONIST LOSARTAN INCREASES PARASYMPATHETIC ACTIVITY INTERNAL CAROTID ARTERIES IN HYPERTENSIVES TREATED IN PATIENTS WITH CHRONIC HEART FAILURE WITH LOSARTAN. S.R. Giliarevsky, L.M. Parfenova, O.A. Boeva G. A. Denisova, T.V. Balahonova, E. V. Oschepkova, 0. N. Epifanova, Dept. of Clinical Pharmacology, Institute for Advanced Medical Studies, Chassovaja st 0. Yu. Atkov, G. G.Arabidze. Cardiology Research Complex Ministry of Health 20, Moscow, Russia of the Russian Federation, Moscow, Russia. Parasympathetic nervous activity (PSNA) is one of important detem1inants of The aim of our study is to evaluate the influence of antihypertensive treatment on the sudden death in patients with cardiovascular diseases. Therefore, drugs effects on dynamics of the blood flow velocity in hypertensive patients. PSNA may be of prognostic importance in patients with heart failure. We estimated the blood flow velocity (Q) and its dynamics in 10 hypertensive In open randomized trial we determined influence of short-term therapy (I week) patients, male and female, aged 53±3, with haemodynarnically insignificant with Losartan 25 mg/day, Captopril 25 mg/day or Placebo on PSNA by heart rate vari atherosclerotic lesions and kinking in carotid and vertebral arteries. Q was estimated ability (HVR) analysis in 27 patients (14 F, 13M, age 46,9±4,3 yrs) with valvular in internal carotid and vertebral arteries from both sides with two-demensional heart diseases and chronic heart failure NYHA Class II-III. HRV was measured at ultrasound images, with 7.0MHz linear array transducer and ACUSON 128XP/10 baseline and after !-week therapy. Group I (F9)- I week Losartan 25 mg/day, Group system. All the patients had never been on antihypertensive treatment or finished 2 I week Captopril 25 mglday and Group 3 I week Placebo. HRV was determined during 5 ruins sitting rest. taking previous drugs 2 weeks before the study. The second study was conducted One week therapy with Losartan 25 mg/day significantly increased PSNA, as after 30 d avs ' 1osartan treatment, 50 mg a d ay. T h e resu 1ts are presented in the Tab le. measured by inccreasing of SDNN, r-MSSD, HF power Mc 2 (p P.89 P.90 Renin Plasma Activity, Angiotensin II and Aldosterone plasma concentration in INR.UENCE OF LOSARTAN FQTASSIUM ON ERYTHROCYTE MEMBRANE STATE patients resistant and nonresistant to antihypertensive therapy IN ESSENTIAL HYPERTENSION E. A. Tabakian, V.V. Dmitriev, V.V. Kukharchuk., G. G. Arabidze 3rd Cherepkm;skaya 15 a Cardiology Research Center, Moscow, Russia. Zhumanoya A.K., Dzhusipov A.K., MD, Shuratova S.G., MD, Ognevskaya S.V. Kazakh Scientific Research lnstiMe of Cardiology, Almaty, Kazakhstan Purpose of the study was to detect differences of Renin-Angiotensin-Aldosterone system(RAAS) in patients resistant and nonresistant to antihypertensive therapy. The detection of blood pressure (BP) was done by clinic, and ambulatory BP The aim of the study was to evaluate membrane-protective action of losartan po• monitoring. Renin plasma activity (RPA), angiotensin II (All) and aldosterone tassium (LOS). 16 patients (11 male and 5 female, 48±2 y, 158±3/102±4 mmHg) plasma concentration were detected by RIA methods. 35 patients after 3 weeks with mild-to-moderate essential hypertension were involved in the study. The first quadriple therapy: atenolol 100 mgiday, enalapril 20 mgiday, amlodipin group included 10 patients with low plasma renin activity (PRA) 0.54±0.08 ng/1/h !Omg/day, hydroclorthiazide 25mg/day was divided on groups: A-n=l7- resistant (<1ng/l/h) and the second group - 6 pts with high PRA - 4.1±1.8 ng/1/h. At the and B-n=l8-nonresistant.Every patient of group A received 3 procedures of baseline and by the 2nd week of treatment with LOS (50±6.25mg once daily) plasma exchange (PE) with elimination a half plasma volume in each procedure. erythrocyte permeability for urine in increasing concentration, osmotic erythrocyte Control points: "I" - after 7 days of wash out period, "2"- after 3 weeks of resistance in 0.5% NaCI, erythrocyte deformability and serum content of medially therapy, "3"- 3 weeks after PE (group"A"), "4","5","6"-4, 8, 12 month theraPv. molecular peptides (MMP). Points 1 2 3 4 5 6 A significant fall of blood pressure level was observed after a 2-week course of Mean 24h A 182± 3,8 170±2,9* 149±2,9* 155±3,8* 162±3,5* 155±3,3* LOS monotherapy in both groups. In patients with low PRA a rise of PRAto 4.13±2.1 ng/1/h (p<0.05) was accom Sist. BP B 185 ±5,0 141±3,3* 138±4, I* - 147±3,4* 143±3,4* panied by the improvement of functional state of erythrocyte membranes: de Mean 24h A 110±1,7 104±1,3* 89±1,8* 93 ±2,3* 96±2,3* 93±2,5* crease of permeability for urine in high concentration from 89.59:±2.24 to Diast. BP B 115± 3,4 88 ±2,1* - 86± 2,3* 89±2,4* 88±2,4* 82.0±1.37 opt. units (p<0.02), increase of osmotic erythrocyte resistance from RPA A 0,96±0,3 0,85±0,3 0,88±0,3 1,27±0,6 \,3±0,6 0,55±0,2 1.71±0.21 to 2.38±0.17 % (p<0.02), decrease of serum content of MMP (for ng.ml.h B 2,3±0,8 2,3±0,7 - 1,4±0,5 0,99±0,3 1,2±0,3 length of wave 286 nm) from 0.359±0.017 U to 0.280±0.022U (p<0.05). In the A-II A 16,8±2,2 11,8±2,5* 10,8±1,4* 9,5±1 ,0* 8,7±0,8* 9,1±1,3* second group no changes of biochemical parameters characterizing functional pg/pl B 17,7±2,4 10,1±1,4* - 9,0±1,4 * 8,2±0,9* 8,7±0,8* state of erythrocyte mebranes were observed. Aldoste- A 239±36 191±32 174±30* 245±36 239±31 ?52±42 Thus, Iosartan potassium administered as monotherapy effectively reduces blood pressure level but also exerts an ability of improving of functional state of cellular rone pg/pl B 368±55 239±44. - 148±22* 207±30* 165±28* membranes in hypertensive patients with low PRA. *p < 0,01 as compared wrth pomt I, The decreasing of All plasma level is result of enalapril intake and one of cases of BP reduction. There was no significant changes RAAS on therapy before and 3 weeks after PE. The decreasing of aldosterone plasma level diuring one year was m group B only. S23 P.91 P.92 ENDOTHELIN AND ALDOSTERONE PLASMA CONCENTRATION AFTER eE runth _ !!. II LOSARTAN ADMINISTRATION IN HYPERTENSIVES. O.Musialik, A.Skoluda, T.Kosicka [). tlltU i , ", r.ka.tudll • .! _llo:•tvriii.. Department of Internal Medicine, Department of Hyperten D pn U•p •tt Df ln \ sion, Medical Academy, Poznan, Poland iitd!!ll l ::la:rn•fi . Pa.L•.ru: Losartan (L) is a high specific and selective antagonist of angiotensin II (All) type AT 1 receptors. L.blocks all actions of circulating and tissue-derived AJI. L.also stimu lates A II 7 receptor directly increasing NO and prostaglandins producing. These well knowu endothelimu derived relaxing factors (EDRF,) inhibit synthesis and release of endothclin (ET-1). ET-1 is the most potent endogenic vasoconstrictor. ET-1 plasma decrease can be one of the factors responsible of ACE -1 and AT1 receptors antagonist antihypertensive effect. Whereas the physiologic effects of aldosterone (A) are increa· sing transepithelial sodium transport in the kidney and other epithelia, the clinical effects of A(hypertension, cardiac hyperthrophy) reflect direct non-epithelial effects via mineralocorticoid receptors in brain and heart. The aim of study was to estimate L. influence on ET-1 and A plasma concentrations in hypertensives. We observed 15 patients with mild to moderate essential hypertension with normal GFR. They were treated with 50 mg L. or L. with 12,5 mg hydrochloro thiazide during 4 weeks. At the begin and in the end of the study the plasma concentra tion of I) ET-1 (RIA, Amershan UK), 2) A (RIA, DPC USA), 3) PRA (RIA, lncstar Corporation USA). Systolic blood pressure (SBP) was 157±12 mmHg and diastolic blood pressure (DBP) was 102±10 mmHg.After one-month therapy 144±12 mmHg and 93±9 mmHg, respectively (p P.93 P.94 BAROREFLEX GAIN IN ESSENTIAL HYPERTENSION THE EFFECT OF RENIN SECRETION IN NORMOTENSIVE AND HYPERTENSIVE COMBINED TRANDOLAPRIL AND DILTHIAZEM THERAPY PATIENTS WITH UNILATERAL RENAL ARTERY STENOSIS ( URAS ). J. Siegelovit*, B. Fiser+, J. Dusek*, Placheta Z*, *Department of Functional Diagnostics and Rehabilitation and +Department of Physiology Medical Faculty, L. Koobs, HW van der Haul, AJJ Woittiez Masaryk University, Brno, Czech Republic Depts of Internal Medicine and Radiology, Twenteborg Hospital, PO Box 7600 SZ Almelo, The Netherlands Baroreflex heart rate sensitivity (BRS, ms/mmHg) increased in patients with essential hypertension due to the combined therapy with dilthiazem and trandolapril in In 3 recently published trials on renovascular hypertension, relief of the comparison with the placebo therapy. The aim ofthe study was to compare the gain of stenosis did not cure hypertension. The question rises if the Goldblatt model the baroreflex including the vasomotor response which has not hitherto been studied. of high renin renovascular hypertension ( RVHT) in men really exists, To We examined 18 patients with mild essential hypertension (men, aged 48±5 years, answer this question we compared the renal renin secretion in hypertensive body weight 88±9 kg) after 3 months of the combined therapy with trandolapril (2 and normotensive patients with URAS. Three case patients ( 1 man and 2 mg,in one morning dose) and dilthiazem (retard, 90 mg, twice a day, EH TD) with women, aged 57-77 yr) who underwent angiography for peripheral vascular mean BRS (±S.D.) 8.2±3.4 and compared with 10 normotensives with high BRS>10 disease proved to have an URAS, without any sign of hypertension or organ ms/mmHg (C-HBRS) and with 10 normotensives with low BRS<5 ms/mmHg (C damage. Nine matched patients with RVHT due to an URAS served as LBRS) and 10 non-treated patients with essential hypertension (EH) with BRS controls. In all patients levels of peripheral renin ( basal, and after 50 mg 4.7±1.8. The release of pressure (200 mmHg) in cuffs placed on both thighs after 5- Captopril ) and of renal vein renin (and aortic renin ) was determined. Tc• minute's ischaemia elicited a decrease in blood pressure (Finapres, Ohmeda) of 10-20 MAG-3 isotope renography, ultrasound kidney examination and creatinin mmHg. The slope (mmHg/s) of the baroreflex mediated return of systolic (SLOPE clearance was established. By definition the blood pressure was higher in SBP) and diastolic blood pressure (SLOPE-DBP) to the original level corresponds to the hypertensive group ( 178 .± 25/104 .± 2 ) than in the normotensive group the baroreflex gain. The Ethics Committee of the Masaryk University Teaching ( 128 .± 12/80 .± 9 mmHg, p =0,018 ). In the hypertensives the basal renin Hospital approved the study. activity ( 10,1 .± 9,5 U vs 1,4 .± 0,6 U, p =0,026), the stimulated renin activity The following values ofSLOPE-SBP and SLOPE-DBP respectively (mean±S.D.) ( 24 .± 10 U vs 5,2 .± 1,8 U, p =0,051 ) and the renin activity in renal vein of were found: EH TD- 0.93±1.33 and 0.55±0.65; C-LBRS- 0.48±0.18 and 0.30±0.14; the affected side ( 9,6 .± 1 ,7 vs 1,13 .± 0,2, p = 0,002 ) were higher than in the C-HBRS- 1.29±0.62 and 118±0.58; EH- 1.04±0.64 and 0.92±0.68. normotensives. Renographic data did not show differences in t max or The values of SLOPE-SBP and SLOPE-DBP in C-LBRS were significantly different tubular excretion. The creatinin clearance was lower in the normotensives from the other groups (ANOV A, p<0.05). ( 39 .± 11 vs 69 .± 28 ml/min, p = 0,005 ). It is concluded that the gain of the whole baroreflex in EH TD corresponds to healthy In hypertensive patients the URAS causes a 5-fold increase in renal renin subjects with high BRS. secretion, as compared with normotensives with URAS, who did not show a Supported by IG A MZ CR 4313-3. renin release on the affected side. Our findings confirm the 2 - k- 1 - c Goldblatt model in patients with RVHT due to URAS. Our results do not give an explanation for the negative results of dilatory procedures in RVHT. S24 P.95 P.96 ANGIOTENSIN-(1-7) EFFECT ON PHOSPHOLIPIDS TURNOVER IS EFFECT OF ANGIOTENSIN II ON PHOSPHOLIPIDS "DE NOVO" MEDIATED BY A SPECIFIC PHOSPHOLIPASE C SYNTHESIS IN THE RAT RENAL CORTEX MM Gironacci , MC Fernandez-Tome, E Speziale, N Sterin-Speziale & C MM Gironacci, MC Fernandez-Tome, E Speziale, C Peiia & N Sterin• Peiia. IQUIFIB (UBA-CONICET), Facultad de Farmacia y Bioquimica, UBA. Speziale. IQUIFIB (UBA-CONICET), Facultad de Farmacia y Bioquimica, Buenos Aires, Argentina UBA, Buenos Aires, Argentina Since Ang-(1-7) can be locally generated in the kidney and plays a key role Since angiotensin (Ang) II influences phospholipase C, D and A2 activities, in the renal function, the aim of the present work was to study the effect of which are a degradative step that precedes the phospholipid (Pis) the heptapeptide on phospholipids (Pis) biosynthesis in the rat renal cortex. reconstitution, we studied the effect of Ang II on rat renal cortical Pls "de Rat renal cortical slices were incubated with 32P during 60 min. Ang-(1-7) novo" synthesis. was added and incubated during 1 and 30 min. The tissue was Rat renal cortical slices were incubated with 32P during 60 min. Ang II was homogenized. The Pis were extracted, separated by TLC, identified by added and incubated during 1, 15 and 30 min. The tissue was autoradiography and quantified by liquid scintillation. homogenized. The Pis were extracted, separated by TLC, identified by Ang-(1-7) (1x10-10 M) caused a biphasic effect on phosphatidylcholine (PC) autoradiography and quantified by liquid scintillation. and phosphatidylinositol (PI) biosynthesis, being inhibitory at 1 min and Ang II (1x10-10 M to 1x10.. M) caused a time-dependent increase in 32P 10 stimulatory at 30 min. The AT1 receptor antagonist, DUP 753 (1x10- M to incorporation into phosphatidylcholine (PC) and phosphatidylinositol (PI). 1x10.. M) did not modify the responses elicited by the peptide. H7 (1x10-7 The increase in PC fraction promoted by the tissue exposure to Ang II M), an inhibitor of protein kinase C (PK C), reversed both the inhibitory and during 1 min was blocked by saralasin (Sar), but was not modified by either stimulatory effects of Ang-(1-7) on 32P incorporation into PC and Pl. DUP 753, an AT1 receptor antagonist, or by PD 123319, an AT2 receptor Dibutyrii-AMPc (dBAMPc) (1x10-7 M), an inhibitor of phospholipase C antagonist. The stimulatory effect of Ang II observed at 15 and 30 min was (PLC), only reversed the Ang-(1-7) response at 1 min on both PC and PI not modified by Sar and PD 123319, but was potentiated by Dup 753 at 30 biosynthesis. However, the PLC inhibitor neomicine (NEO) (1x10-7 M) was min. The increase in PI biosynthesis caused by the peptide was blocked by without of effect on Ang-(1-7) actions. Sar, DUP 753 and PD 123319 at 1 min, was not modified neither by Sar nor Our results suggest that the biphasic effect of Ang-(1-7) on Pis turnover in by PD 123319 at 15 and 30 min, but was potentiated by DUP 753 at 30 min. the rat renal cortex is mediated by stimulation of a specific PLC via Our results suggest that the short-term effect of Ang II on Pis biosynthesis in the rat renal cortex seems to be mediated by a non-AT,-non-AT2 receptor, activation of a receptor distinct from AT1• while the long-term effect seems to be upregulated by an AT1 receptor population. P.97 INTERACTION BETWEEN THE SYMPATHETIC NERVOUS SYSTEM ( SMS) AND ANGIOTENSIN- II. A.J.J. Woittiez, W. Roeloffzen and P. de Leeuw Twenteborg Hospital Almelo, Department of Internal Medicine Postbus 7600, 7600 SZ Almelo Animal studies have suggested that Angiotensin-11 (All ) has a stimulating effect on the sympathetic nervous system. In 2 studies we investigated the influence of A-ll on the SNS. Seven patients with essential hypertension were in random order allocated to treatment for four weeks with Losartan ( 50 mg bid ) or Doxazosin ( 4 mg bid ) or placebo. Of these patients we determined the pressor-dose response curves to infused A-ll ( 1,25-10 ng/kg/min ) and to infused phenylephrine ( PE ) ( 0,5 - 4 ng/kg/min ) After wards we determined the acute BP response to Doxazosin after pre treatment with a diuretic or an ACE inhibitor for 4 weeks. Studies were done after an overnight fast and approximately 1 hour after having taken the morning dose. Blood pressure and heart rate were measured semi-continuously with an automatic device ( Dinamap ). Doxazosin and Losartan equally lowered blood pressure from 170.± 10 1 109 .± 6 to 163 .± 8/93 .± 5 mmHg. Losartan completely blocked the effects of infused All, while Doxazosin did not. The responses toPE infusion were not abolished by Losartan, while Doxazosin caused a shift to the right of the pressor- dose response curve. The BP response to Doxazosin did not differ between diuretic pre-treatment ( high A-ll ) or ACE-i pre-treatment ( low A-ll ) In conclusion our studies do not give support for any interaction or modulation of A-ll on the SNS. S25