Antidepressant Activity of Fosinopril, Ramipril and Losartan, but Not of Lisinopril in Depressive Paradigms of Albino Rats and Mice

Indian Journal of Experimental Biology Vol. 46, March 2008, pp. 180-184

Antidepressant activity of fosinopril, ramipril and losartan, but not of lisinopril in depressive paradigms of albino rats and mice

Veena Nayak & P A Patil* Department of Pharmacology & Pharmacotherapeutics, J.N.Medical College, Belgaum 590 010, India

Received 15 January 2007; revised 15 January 2008

Fosinopril, ramipril and losartan significantly decreased the duration (sec) of immobility in forced swim test and were comparable to amitriptyline. The duration of immobility were significantly decreased in fosinopril, ramipril and losartan in the tail suspension test and were comparable to amitriptyline. Only losartan significantly increased the rearing number of entries, time spent (sec) in open arm and in light area in comparison to control animals. Fosinopril and ramipril and not lisinopril showed significant antidepressant activity while losartan showed a significant antidepressant and anxiolytic activity. Present findings suggest that these drugs could be better antihypertensives in hypertensive patients with co- morbidity like depression or anxiety.

Keywords: Anxiety, Depression, Fosinopril, Lisinopril, Losartan, Ramipril

Physiological depression and anxiety when become possess antidepressant and anxiolytic activity like severe and chronic lead to a variety of psychiatric captopril and enalapril. A report regarding quinapril13 disorders. Quite often such mood disorders could be indicates that all ACE inhibitors may not share secondary to a number of cardiovascular and antidepressant and anxiolytic activity and such endocrinal disorders1,2 requiring treatment with two activities are not probed with other ACE inhibitors drugs, one for physical or metabolic and the other for used clinically. It is therefore planned to investigate associated mental disorder. Logically, a single drug the effect of widely used, chemically heterogeneous that can control the physical and associated mental ACE inhibitors14 with varying lipophilicity15 viz. illness would be an ideal agent for the treatment of fosinopril, ramipril and lisinopril for their such co morbid conditions. antidepressant and anxiolytic activity in male Wistar Interestingly, angiotensin converting enzyme (ACE) rats and Swiss mice. inhibitors like captopril3, perindopril4 and ceronapril5 have been reported to possess antidepressant activity in Materials and Methods experimental animals. Similarly losartan, an Animals—Male adult Wistar rats and Swiss mice, angiotensin II receptor blocker has also been reported weighing between 150-250 g and 20-30 g to possess antidepressant activity in experimental respectively, were obtained from the central animal animals6. Moreover captopril7, 8 and enalapril8 have house of the institute and were kept in the laboratory been reported to control not only blood pressure but for about 10 days in 12:12 hr L:D cycle. Throughout also improve the depressed mood and cognition in the experiment the animals were fed with laboratory hypertensive patients. In addition captopril9,10, chow (Amrut Brand) and water ad libitum. Animals enalapril11 and losartan11,12 have been shown receiving alprazolam orally were fasted overnight experimentally to exert anxiolytic activity both in prior to the day of experiment and experiments were normotensive and hypertensive rats. conducted between 09.00-14.00 hrs. Due to the common mechanism of action, other The study was approved by Institutional Animal ACE inhibitors used clinically could be expected to Ethical Committee formed as per the guidelines of CPCSEA, New Delhi. ______Drugs and doses—Amitriptyline (Inj. Typtin, Sterfil *Correspondent author: Labs Ltd), alprazolam (Tablets Alprax, Torrent Ltd), Phone: 0831-2473777 Ext: 1828 Fax: 91-0831-470759 lisinopril (Tablets Lipril, Lupin Ltd) and losartan E-mail: [email protected] (Tablets Angizaar, Carsynoa, Microlabs) were NAYAK & PATIL: ANTIDEPRESSANT ACTIVITY OF ACE INHIBITORS 181

purchased locally. Fosinopril and ramipril were The plus maze apparatus consists of two open obtained as generous gift samples from Cipla Ltd. (50 × 10 cm) and two side-closed arms (50 × 10 × Rat and mice equivalent doses in mg/kg body 40 cm) without roof, elevated 50 cm from the floor. weight of clinical doses were calculated as mg/kg The pretreated animals were placed individually for body weight with the help of the table cited earlier16 5 min at the center of the elevated plus maze facing and were 27.0 for amitriptyline (AMT), 0.045 for the head towards an open arm. The number of entries alprazolam (AZM), 1.8 for fosinopril (FSL), 0.23 for into the open or closed arm and the time spent in each ramipril (RML), 1.8 for lisinopril (LSL), 10.0 for arm were recorded. At the same time, number of rears losartan (LTN); while the corresponding doses for in the open arm was recorded. mice were 7.8 for AMT, 0.52 for FSL, 0.06 for RML, The percentage of the number of entries (against 0.52 for LSL, and 2.88 for LTN. All the drugs except the total number of entries both in open and closed AZM were dissolved in distilled water while AZM arms) and time spent in the open arm were calculated was suspended in 2% gum acacia. All drugs were for each group. Similarly mean number of rears freshly prepared and were administered in a single ip (standing on the hind limbs) for each group was dose in the volume of 0.5 ml to groups of mice (n=6, calculated. in each) and 1.0 ml to groups of rats (n=6, in each), d) Light–dark arena20: It consists of a wooden box while alprazolam suspension was given orally in the (50 × 30 × 35cm) placed on a table, 1m above floor volume of 1 ml to the rats. Equal volumes of either level. A partition with a gap of 7.5 × 7.5cm at the gum acacia 2% suspension or normal saline were centre of its lower border was fixed to separate 2/5th of administered through corresponding route to the the base from the remaining 3/5th . The smaller 2/5th control group. chamber was painted black and the other one (3/5th of Behavioral studies—a) Antidepressant activity the base) was painted white on all four sides . The studies were carried out in rats using forced swim test chamber painted black was illuminated with red light 17 paradigm as described earlier. while the other chamber was brightly illuminated with Briefly, male adult rats weighing 160-180 g were a 100 W light source located 17 cm above the box. plunged into a vertical plexiglass cylinder (40 cm Pretreated rats were placed in the centre of the bright height 18 cm diam) containing 15 cm of water column area. The number of rearings, entries into and time maintained at 25°C and left there for 5 min. The spent in light area were recorded over a period of duration of immobility in seconds as indicated by the 5 min. The mean number entries and rears and animal floating motionless in the water making only percentage of time spent were calculated for each those movements necessary to keep its head above group. water was noted. Animals were trained for 15 min, 24 The effect of all the drugs used in the present study, hours prior to the experiment. After the experiment, on locomotor activity was tested using the animals were then allowed to dry for 15 min actophotometer (M/S INCO) before returning to their individual cages. Group Statistical analysis—The results were analyzed by mean of immobility time was calculated in treated and one-way ANOVA followed by Dunnet’s test using control animals. Graph pad prism software and P ≤ 0.05 was b) Tail suspension test was carried out in mice as considered significant. 18 described earlier . The mouse pretreated with drug/vehicle was Results suspended from the hook hanging at the center of a Forced swim test and tail suspension test—The horizontal rod placed on 2 metallic stands kept 35 cm mean duration of immobility in the FSL, RML and apart. An adhesive tape stuck 2 cm proximal to the LTN treated groups were significantly (P≤0.01, tail tip was used to suspend the animal through the ≤0.05) reduced as compared to that of the control hook hanging about 35 cm distance from the ground. group and was comparable to that of AMT. However Immobility time in seconds was recorded by assessing LSL failed to show antidepressant activity in both the motionless hanging of the mice over a period of paradigms (Table 1). 6 min. Elevated plus maze—The mean number of entries c) Anxiolytic activity was studied using elevated into the open arm in the control and treated groups plus maze as described earlier19. though did not significantly differ, the mean of 182 INDIAN J EXP BIOL, MARCH 2008

percentage entries into open arm was significantly Locomotor activity—The locomotor activity in the increased in the LTN (P≤0.05) and AZM (P≤0.01) AZM (15.17±1.16) treated group was significantly treated animals. Similarly the mean number of rears (P<0.05) decreased in comparison to control group and percentage of time spent in the open arm was (21.83±1.22). There was no significant change in the significantly increased in the LTN (P≤0.05) and AZM locomotor activity in the AMT (21.17±1.42), FSL (P≤0.01) treated animals (Table 2). (22±1.18), RML (21.50±1.99), LSL (19.83±1.74) and Light dark arena—The mean number of rears and LTN (20±2.38) treated groups was observed. percentage of time spent in the light area in the LTN and AZM treated group was significantly increased Discussion (P<0.05, ≤0.01) when compared to that of control The findings of the present study in both the group (Table 2). models of depression viz. forced swim test and tail suspension test clearly indicate that FSL, RML and Table 1—Effect of various treatments on depression paradigms [Values are mean ± SE from 6 animals in each group] LTN have significant antidepressant activity, comparable to that of AMT. The antidepressant Treatment Dose (mg/kg) Immobility time (sec) activity of LTN observed in the present study agrees Groups Rat Mice Forced Tail 6 swim test suspension with an earlier report however, to the best of our in rats test in mice knowledge the antidepressant activity of FSL and RML is being reported for the first time. Normal 1 ml 0.5 ml 176 ± 218.7 ± saline 5.26 12.25 Dysregulated hypothalamopituitary adrenal axis 22 Amitriptyline 27 7.8 142 ± 159.7 ± (HPA) leading to increased cortisol levels and 3.19** 2.33** decreased BDNF level23 have been implicated with Fosinopril 1.8 0.52 143.5 ± 153.2 ± depressive disorders and restoration of normalcy of 3.74** 2.94** HPA axis by captopril has been correlated with its Ramipril 0.225 0.065 158.8 ± 163.5 ± 7 3.46* 3.35** antidepressant activity in a hypertensive patient . Lisinopril 1.8 0.52 165.7 ± 203.2 ± Involvement of glucocorticoids in the pathogenesis of 3.39 3.87 depression has been confirmed in an experimental Losartan 10 2.88 148.3 ± 158.2 ± study24. Antidepressant activity of captopril has also 3.80** 2.15** 7 been reported to be mediated through enkephalin and One-way ANOVA followed by Dunnet’s test. ACE inhibitors used in the present study could be P values: *<0.05, **<0.01 (vs control group) acting in the same way as captopril.

Table 2—Effect of various treatments on anxiety paradigms [Values are mean ± SE from 6 animals in each group]

Elevated plus maze Light dark arena Treatment Dose Number Number Open arm Time Rears in Time Time Rears in Groups (mg/kg) of open of total entries spent in open arm spent in spent in light area arm arm (%) open arm light area light area entries entries (%) (%)

Gum acacia 1.0ml 2.67 ± 9.83 ± 24.71 ± 9.17 ± 2.33 ± 27.5 ± 9.17 ± 3.17 ± 0.67 1.22 4.54 3.24 0.33 6.18 2.06 0.40 Alprazolam 0.045 3.67 ± 7.5 ± 48.92 ± 22.06 ± 3.83 ± 49.5 ± 16.50 ± 5 ± 0.95 1.36 6.79** 3.43** 0.48* 5.09 1.7** 0.58* Fosinopril 1.8 3 ± 8.67 ± 37.41 ± 12.67 ± 1.67 ± 19.67 ± 6.55 ± 2.83 ± 0.57 1.76 4.49 2.45 0.33 2.47 0.82 0.31 Ramipril 0.225 2.5 ± 7.33 ± 34.82 ± 8.99 ± 1.67 ± 18.67 ± 6.39 ± 2.33 ± 0.22 0.33 4.22 1.78 0.21 2.09 0.67 0.42 Lisinopril 1.8 2.17 ± 6.16 ± 35.06 ± 7.44 ± 1.67 ± 15.67 ± 5.39 ± 2.67 ± 0.60 1.47 2.99 0.69 0.33 2.01 0.70 0.49 Losartan 10 4.83 ± 9.16 ± 45.55 ± 19 ± 3.33 ± 45.50 ± 19 ± 3.33 ± 0.30 0.94 1.87* 1.63* 0.21* 2.17 1.63* 0.21*

One-way ANOVA followed by Dunnet’s test. P values: *0.05; **<0.01 (vs control group) NAYAK & PATIL: ANTIDEPRESSANT ACTIVITY OF ACE INHIBITORS 183

It is unlikely that ACE antagonists used in the through central GABAergic mechanisms, central present study augment central synaptic sympathetic over activity is also involved in norepinephrine (NE) level in order to exert anxiogenesis. antidepressant activity, since angiotensin II itself is Captopril has been reported to relieve the signs of said to augment the synaptic NE release14. depression in a hypertensive patient with recurrent Lack of antidepressant activity in rats treated with unipolar major depression7 and improved the quality lisinopril could be explained on the basis of its poor of life in hypertensive individuals30. The observed lipophilicity15, despite its passage through blood brain antidepressant and anxiolytic activity of LTN; barrier. It is well known that, the lipophilicity is one antidepressant activity of FSL and RML indicate that, of the determinants of tissue penetration by drug these drugs can improve the quality of life in molecules to exert pharmacological actions. hypertensive individuals. These drugs may be In the present study only LTN, an angiotensin preferred to treat hypertensive patients with mood receptor blocker, in the dose of 10 mg/kg but not disorders, provided the present findings could be 5 mg/kg showed significant anxiolytic activity in both extrapolated to humans. Such patients need the the models of anxiety (elevated plus maze and light treatment with an antihypertensive and an dark arena) and was comparable to that of AZM. antidepressant. When these drugs particularly LTN is These findings of the present study are in agreement used as an antihypertensive might reduce the dosage with an earlier report11 wherein LTN was reported to requirement of potentially toxic antidepressants and produce dose dependent anxiolytic activity in the same needs clinical evaluation. hypertensive rats, while its anxiolytic activity was observed only with a higher dose (10 mg/kg) in Acknowledgement normotensive rats11. Thanks are due to Messrs M D Mallapur, Increased central norepinephrine (NE) is often statistician, M D Kankanwadi, A V Karvekar, and implicated with anxiety. Anxiolytic activity of LTN in M R Ambewadi for technical assistance. hypertensive rats has been attributed to its selective References blockade of AT1 (anxiogenic) receptors leading to 5, 26, 27 1 John M J, Drug Therapy: The Medical Management of suppressed NE release . Depression (review), N Eng J Med, 353 (2005) 1819. All the three ACE inhibitors viz. FSL, RML and 2 Shrivastava S & Kochar M S, The dual risks of depression LSL used in the present study, failed to show and hypertension, Postgraduate Med, 111 (2002) 1. 3 Giardina W J & Ebert D M, Positive effects of captopril in significant anxiolytic activity and there is paucity of the behavioral despair swim test, Biol Psychiatry, 25 (1989) information regarding their influence on anxiety. 697. However, captopril and enalapril have been reported 4 Martin P, Massol J, Scalbert E & Puech A J, Involvement of to exert anxiolytic activity in hypertensive rats but not angiotensin converting enzyme inhibition in reversal of in normotensive ones11, 25. The lack of anxiolytic helpless behavior evoked by perindopril in rats, Eur J Pharmacol, 187 (1990) 165. activity of FSL, RML and LSL in the present study 5 Gard P R, The role of angiotensin II in cognition and could be explained on the basis of normotensive rats behaviour, Eur J Pharmacol 438 (2002) 1. being used and the present findings agree with an 6 Vijayapandi Pandi & Nagappa A N, Biphasic effects of earlier report wherein enalapril failed to produce Losartan Potassium on Immobility in Mice, Pharmaceutical Soc Japan, 125 (2005) 653. anxiolytic activity in normotensive rats. 7 Germain L & Chouinard G, Treatment of recurrent Unipolar The anxiolytic effect of renin angiotensin system Major Depression with captopril (case report), Biol antagonists could be attributed to increased central Psychiatry, 23 (1988) 637. GABA activity, since angiotensin II has been reported 8 Braszko J J, Karwowska P W, Halicka D & Gard P R, 28 Captopril and enalapril improve cognition and depressed to decrease central GABA activity . It is difficult to mood in hypertensive patients, J Basic Clin Physiol explain why ACE inhibitors used in the present study Pharmacol, 14 (2003) 323. failed to show anxiolytic activity. However, except 9 Packaerts J, Raaijmakers W & Blokland A, Effects of AZM none of the treatments significantly changed myocardial infarction and captopril therapy on anxiety locomotor behavior. This finding indirectly indicates related behaviors in the rat, Physiol Behav, 60 (1996) 43. 10 Costal B, Domeney A M, Gerrard P A, Horovitz Z P, Kelly insignificant changes in central GABA activity and M E, Naylor J R & Tomkins D M, Effects of Captopril and that probably explains the lack of their anxiolytic SQ29852 on Anxiety related behaviors in Rodent and activity. Though, anxiolytic activity is mediated Marmoset, Pharmacol Biochem Behav, 36 (1990) 13. 184 INDIAN J EXP BIOL, MARCH 2008

11 Srinivasan J, Suresh B & Ramanathan M, Differential 22 Sadock B J & Sadock V A, Mood disorders, in Kaplan and anxiolytic effect of enalapril and losartan in normotensive Sadock’s Comprehensive textbook of psychiatry. 8th ed. and renal hypertensive rats, J Physiol Behav, 78 (2003) 585. (Vol 1) (Lippincott Williams and Wilkins, Philadelphia) 12 Braszko J J, Kulakowska A & Winnicka M M, Effects of 2005, 534. Angiotensin II and its receptor antagonists on motor activity 23 Stahl S M, Anxiolytics and Sedative-Hypnotics, in Essential and anxiety in rats, J Physiol Pharmacol, 54 (2003) 271. Psychopharmacology 2nd ed. (Foundation books, Cambridge 13 Gunduz H, Georges J L & Fleishman S, Quinapril and University Press, New Delhi) 2000, 297. Depression (letter), Am J Psychiatry, 156 (1999) 114. 24 Boyle M P, Brewer J A, Funatsu M, Wozniak D F, Tsien J Z. 14 Brunton L L, Lazo J S, Parker K L & Goodman Gilman A, Izumi Y & Muglia L J, Acquired deficit of forebrain Renin and angiotensin, in The Pharmacological basis of glucocorticoid receptor produces depression like changes in therapeutics, 11th ed. ( McGraw Hill, New York) 2001,789. adrenal axis regulation and behavior, Neuroscience, 102 15 Piepho & Robert W, Overview of the angiotensin converting (2005) 473. enzyme inhibitors, Am J Health Syst Pharm, 57 (2000) 25 Wilson W, Voigt P, Bader M, Marsden C A & Fink H, Supp1 S3. Behaviour of the transgenic (mREN2) 27rat, Brain Res, 729 16 Ghosh M N, Toxicity studies, Fundamentals of experimental (1996) 1. pharmacology, 3rd ed. ( Hilton and company, Kolkota) 2005, 26 Okuyama S, Sakagawa T & Inagami T, Role of the 17 Porsolt R D, Pichon M L & Jalfre M, Depression: a new Angiotensin II Type-2 Receptor in the mouse Central animal model sensitive to antidepressant treatments, Nature, Nervous System (Review), Jpn J Pharmacol, 81 (1999) 259. 266 (1977) 730. 27 Okuyama S, Sakagawa T, Chaki S, Imagawa Y, Ichiki T & 18 Steru L, Chermat R, Thierry B & Siman P, The tail Inagami T, Anxiety like behavior in mice lacking the suspension test : A new method for screening antidepressants angiotensin II type 2 receptor, Brain Res, 821 (1999) 150. in mice, Psychopharmacology, 85 (1985) 367. 28 De-Pei Li & Hui-Lin pan, Angiotensin II attenuates synaptic 19 Pellow S, Chopin P, Fil S E & Briely B, Validation of open- GABA release and excites paraventricular rostral closed arm entries in elevated plus maze as a measure of ventrolateral medulla output neurons, J Pharmacol Exp Ther, anxiety in the rat, J Neurosci Methods, 14 (1985) 149. 313 (2005) 1035. 20 Costall B, Domeney A M, Gerrad P A, Kelly M E & Naylor 29 Hadjiivanova C H & Georagierv V, Invitro effect of R, Zacopride: anxiolytic profile in rodents and primate angiotensin II on GABA release in rat hippocampus, models of anxiety, J Pharm Phamacol, 40 (1988) 302. Neuropeptides, 32 (1998) 431. 21 Broom D C, Jut Kiewicz E M, Rice K C, Traynor J R & 30 Croog S H, Levine S, Testa M A, Brown B, Bulpitt C J & Woods J H, Behaviour effects of δ opioid receptor agonists: Jenkins C D, The effects of antihypertensive therapy on potential antidepressants, Jpn J Pharmacol, 90 (2002) 1. quality of life, N Eng J Med, 314 (1986) 1657.