Differential anxiolytic effect of enalapril and losartan in normotensive and renal hypertensive rats.
The effect of angiotensin-converting enzyme (ACE) inhibitor enalapril (EPL) (2 and 4 mg/kg), angiotensin (AT) II receptor antagonist losartan (LRN) (5 and 10 mg/kg), and anxiolytic drug diazepam (DZP) (0.5 mg/kg) on anxiety parameters were evaluated in experimentally induced renal hypertensive rats (RHR). Renal hypertension was induced in Wistar strain male albino rats weighing 200-250 g by following the method of Goldblatt. The animals having systolic blood pressure more than 180-210 mm Hg were subjected to open-field exploratory behaviour, elevated plus maze behaviour, and social interaction tests of anxiety. The RHR showed hyperactivity in open-field behaviour and anxiogenicity in elevated plus maze and social interaction tests. Losartan (5 and 10 mg/kg) and DZP (0.5 mg/kg) significantly attenuated the hyperactivity and anxiogenic behaviour in experimentally induced hypertensive rats and induced anxiolysis in normotensive rats (NTR). Enalapril reversed the hypertension-induced alteration only at higher dose (4 mg/kg) and failed to show any effect in NTR. It can be concluded that renin angiotensin aldosterone system (RAAS) has a significant role on behaviour, and LRN has shown better effect in reversing the hyperactivity and anxiogenicity in the experimentally induced hypertensive rats, indicating a possible role of AT receptor in the mediation of anxiolysis.
Srinivasan
J
J
Neuropharmacology Laboratory, Department of Pharmacology, J.S.S. College of Pharmacy, Ootacamund TN 643 001, India.
Suresh
B
B
Ramanathan
M
M
D047228:Angiotensin II Type 1 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D014151:Anti-Anxiety Agents; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001007:Anxiety / Q000523:psychology*; D001794:Blood Pressure / Q000187:drug effects; D003975:Diazepam / Q000494:pharmacology; D004656:Enalapril / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D006977:Hypertension, Renal / Q000188:drug therapy / Q000523:psychology*; D019808:Losartan / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012919:Social Behavior
D047228:Angiotensin II Type 1 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors; D014151:Anti-Anxiety Agents; D000959:Antihypertensive Agents; D004656:Enalapril; D019808:Losartan; D003975:Diazepam