Strain differences in the anxiolytic effects of losartan in the mouse

Anxiolytic effects of the angiotensin ATI receptor antagonist losartan were studied in the elevated plus maze (EPM) and the light/dark test (LDT) in d ifferent mouse strains as were responses to angiotensin II and acetylcholin e in isolated ascending colon. There were no significant strain differences in behaviour on the EPM, and diazepam was anxiolytic in C57BL/6, DBA/2 and BKW mice. Losartan was anxiolytic in BKW only. In the LDT, there were sign ificant strain differences, with BKW mice exhibiting greatest anxiety-like behaviour; losartan was ineffective in this test. In vitro responses to ang iotensin II and acetylcholine were significantly smaller in BKW than in C57 BL/6 and DBA/2. These results indicate that the mouse strain exhibiting lea st angiotensin receptor function is the most responsive to the anxiolytic e ffects, suggesting a possible relationship between angiotensin receptor. fu nction and anxiolytic response to losartan. (C) 2001 Elsevier Science Inc. All rights reserved.