Alin Ciobica

P02-170 Comparative effects of captopril, losartan and PD123319 on the memory processes in rats

Aims Renin-angiotensin system in the central nervous system participates in the processing of sensory information, learning and memory processes. Inhibitors of renin-angiotensin system, particularly angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists are reported to have potential effects in various learning and memory processes. In the present study we assessed the effects of angiotensin converting enzyme inhibitor captopril and the angiotensin AT1 receptors antagonists, lostartan and PD123319, in learning and memory processes by means of Y-maze and passive avoidance tasks. The anxiety state was measured in elevated plus maze. Methods Male Wistar rats were divided into three groups: 1. sham-operated; 2. Captopril; 3. Losartan; 4. PD123319. All drugs were stereotaxically icv injected, rather than captopril (i.p.). Learning and memory tests began 2 weeks after the operation, and the ability of the rats to acquire the operant task was studied by means of Y-maze task and passive avoidance task, respectively. The anxiety state was measured in elevated plus maze. Results Captopril, losartan and PD123319 significantly impaired spatial memory in Y-maze task, suggesting significant effects on short-term memory. In passive avoidance task, all drugs, significantly decreased step-through-latency, suggesting significant effects on long-term memory. In elevated plus maze measuring anxiety, all drugs diminished anxiety state. Conclusions These results suggest the involvement of the brain renin-angiotensin system in learning and memory formation.

P02-169 Behavioral changes induced by angiotensin AT1 receptors blockade in the rat brain

Aims The brain renin-angiotensin system is involved in learning and memory, but the actual role of angiotensin II and its metabolites in this process has been difficult to comprehend. In the present study we assessed the role of the angiotensin AT1 receptors in certain behavioral effects of angiotensin II using their selective antagonist losartan and PD123319, intracerebroventricularly (icv) administrated. Methods Male Wistar rats were divided into three groups: 1. sham-operated; 2. Losartan; 3. PD123319. All drugs were stereotaxically icv injected. Learning and memory tests began 2 weeks after the operation, and the ability of the rats to acquire the operant task was studied by means of Y-maze task and passive avoidance task, respectively. The anxiety state was measured in elevated plus maze. Results Losartan and PD123319 significantly impaired spatial memory in Y-maze task, suggesting significant effects on short-term memory. In passive avoidance task, both angiotensin II antagonist, significantly decreased step-through-latency, suggesting significant effects on long-term memory. In elevated plus maze measuring anxiety, both drugs diminished anxiety state. Conclusions Our results suggest the considerable involvement of the brain ATi angiotensin receptors in the cognition improving effects of angiotensin.