Role of Captopril in Reversal of Anterograde and Retrograde Experimental Amnesia

The present study was designed to investigate the effect of captopril (20mg kg , i.p.) angiotensin 1 converting enzyme (ACE) inhibitor in learning and memory and on scopolamine (3mg kg , i.p), sodium nitrite 1 (75 mg kg , i.p.) and BN52021 (15mg kg , i.p.) a platelet activating factor (PAF) receptor antagonist, induced 1 1 amnesia in mice using water maze test. All the agents were administered 30 min. prior to first acquisition trial for 4 consecutive days and on 5 day during the retrieval trial. Captopril reduced escape latency time (ELT) and th enhanced time spent (TS) in target quadrant (TQ) and significantly reversed scopolamine, sodium nitrite and BN52021 induced attenuation of decrease in ELT and higher TS in TQ during the acquisition and retrieval trials respectively. Findings indicate that captopril reverses anterograde amnesia of scopolamine and sodium nitrite and also reverses retrograde amnesia of sodium nitrite and BN52021. It can be concluded that captopril reverse scopolamine and sodium nitrite induced anterograde amnesia possibly by partial inhibition of angiotensin converting enzyme (ACE) and partially by scavenging reactive oxygen species. Its ameliorative effect on retrograde amnesia of sodium nitrite and BN52021 may be exclusively due to scavenging of free radicals probably by sulphahydral group which is present in its structure.