Memory enhancement by the angiotensinergic system in the crab Chasmagnathus is mediated by endogenous angiotensin II

In previous work with the crab Chasmagnathus, it was reported that either e xogenous angiotensin II (ANGII) or angiotensin IV (ANGIV), have an enhancin g effect on long-term memory, which involves an association between context and an iterative danger stimulus (context-signal memory, CSM). Present res ults indicate that Dival, an ANGIV antagonist, reverts the facilitatory eff ect of ANGIV but not that of ANGII, whereas saralasin but not Dival, disrup ts CSM. These findings suggest that ANGII is the endogenous angiotensin tha t plays a significant role in long-term memory, while the ANGIV receptor wo uld not be encompassed in the cascade of events related to crab's CSM. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.