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 exogenous angiotensin II (ANGII) or angiotensin IV (ANGIV), have an enhancing effect on long-term memory, which involves an association between context and an iterative danger stimulus (context-signal memory, CSM). Present results indicate that Dival, an ANGIV antagonist, reverts the facilitatory effect of ANGIV but not that of ANGII, whereas saralasin but not Dival, disrupts CSM. These findings suggest that ANGII is the endogenous angiotensin that plays a significant role in long-term memory, while the ANGIV receptor would not be encompassed in the cascade of events related to crab's CSM.