Abstract: The relationship between facilitating effect of vasopressin onmemory consolidation and GABA-nergic system in CNS was furtherinvestigated. The arginine-8-vasopressin (AVP) and GABA-nergic receptor'sagonist muscimol or antagonist picrotoxin were administeredintracerebroventricularly (icv). The step-down passive avoidancebehavioral paradigm was used. 1. The acquisition processes were not accelerated, but the memoryconsolidation processes were facilitated significantly after administrationof AVP 1 hr. prior to acquisition session. The animals which weretreated with AVP showed a higher capacity of retention than thecontrols. The effective dosage of AVP is about 30ng/rat. 2. The muscimol (100ng/rat) was injected icv. immediately afteracquisition session, the retention of the experimental group injectedwith AVP was still significantly higher than control of saline in thepassive avoidance behavior. However, after administration of picrotoxin(100ng/rat)in the same way, the effect of AVP decreased when thedosage of picrotoxin was increased to 300ng/rat, the effect of AVP waseliminated entirely. These experimental results suggested again that the effect of AVPfacilitating memory consolidation processes was a central effect, and theaction of GABA-nergic system in CNS might be involved in thefacilitating effect.

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