[Effect of XXXX on hippocampal response during long-term post-tetanic potentiation and @entity308 of the medial septum and dentate gyrus].

@entity1617 @entity308 @entity95 @entity934
Evoked potentials (EPs) of the dorsal hippocampus were recorded in non-immobilized non-anaesthetized @entity95 before and after tetanization of the medial septum and the dentate fascia. Changes of @entity934 ( @entity1617 ) efficiency were tested during long-lasting potentiation (LLP) and @entity308 ( @entity308 ). Increase in the amplitude of the EP fast component (population spike) during microiontophoresis of @entity1617 was used as an index of @entity1617 efficiency. In various tests both decrease and enhancement of @entity1617 efficiency after tetanization were observed independent of the LLP or @entity308 appearance. "Relative" @entity1617 efficiency in most cases decreased during LLP and enhanced during @entity308 . These changes were nonspecific since they were observed in response to the stimulation of both medial septum (cholinergic input), and dentate fascia (non-cholinergic input). Reactions to the stimulation of the control (non-tetanized) input were mainly depressed with diminution of @entity1617 efficiency. The above experiments do not confirm the hypothesis that LLP and @entity308 are based on respective changes in the sensitivity of the subsynaptic membrane to the transmitter. The most probable LLP mechanism seems to be the enhancement of synaptic efficiency due to increased release of the transmitter. @entity308 mechanisms probably include changes at the level of the postsynaptic membrane and call for further analysis.
