Angiotensin II AT1 receptor blockade by telmisartan reduces impairment of spatial maze performance induced by both acute and chronic stress.

Introduction: Despite recognition of stress as a causation of severe neuropsychological dysfunctions, no casual and clinically effective anti-stress therapeutic strategy has yet been found. We have previously shown that blockade of initial stress response by angiotensin receptor blockers alleviates the negative effect of prolonged stress on cognitive non-spatial functions of rats. Here we aimed to find whether telmisartan reduces stress-related memory decline in spatial hippocampal-dependent learning tasks conditioned upon differences in level of stress induced by aversive nature of memory tests.

Methods: Male Wistar rats were exposed to chronic restraint stress for three weeks and daily treated with either vehicle or telmisartan (1 mg/kg). Afterwards rats were tested in three spatial learning and memory paradigms: Morris water maze (MWM), radial arm maze (RAM), and Barnes maze (BM).

Results: Stressed animals demonstrated significantly impaired performance in all the tests, which was normalized in the animals stressed and treated with telmisartan. Interestingly, despite the fact that MWM and RAM are more stressful, which affects animal behavior, therefore considered less sensitive than BM, more significant effect of telmisartan was found in MWM and RAM than BM.

Conclusions: AT1 angiotensin receptor blockade attenuates negative effect of both acute and chronic stress on spatial memory.