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<O.OI) more a priori defined ri sk or disease factors) will be It is concluded that after the combined treatment with trandolapril and veraparnil, BRS randomized. The primary endpoints are composite myocardial values in patients with essential hypertension correspond to the values of healthy infarction, congestive heart failure and cardiac mortality in at subjects. Supported by IG A MZ CR 4313-3. least 1450 patients, expected enrollment 2 yrs from Oct. 1997 and expected follow-up 4-6 yrs. Thus, the VALUE study will be the first antihypertensive event study comparing the effectiveness of the widely used , modern and safe CCB amlodipine with the new ATl-receptor blocker valsartan. 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.