Postsynaptic, but not presynaptic, activity controls the early time course of long-term potentiation in the dentate gyrus

摘要: The early time course (less than 1 hr) of long-term potentiation (LTP) in the dentate gyrus guinea pig hippocampal slice was examined using extracellular recordings from outer two-thirds dendritic layer. LTP induced by a single brief (2-40 impulses) high-frequency (20-400 Hz) train, or pairing test stimulus with heterosynaptic train. induction facilitated blockade fast GABAergic postsynaptic inhibition. It found that, irrespective conditions and amount induced, onset characterized latency few seconds following event, rapid 30 sec growth phase. After 1-2 min period little no further growth, decayed but highly variable manner, cases which more 60% peak value remained hr after to completely within 10 min. Factors increasing presynaptic activity (frequency number afferent stimulations) during event did not affect relative decay. Repetitive be necessary condition for eliciting long-lasting (greater hr), as shown experiments impulse paired such increased intensity, temporal two weak trains, reduced inhibition, all Moreover, partial pharmacological NMDA receptor channels In conclusion, associated activation appeared main factor governing stability gyrus.