Abstract
The cholinergic input to the hippocampus originates in the septum and diagonal band. A bath application of carbachol, a cholinergic agonist, induced different patterns of rhythmical waves depending on its concentration in guinea pig hippocampal slices. Tetanus-induced long-term potentiation (LTP) was differentially facilitated under several concentrations of carbachol. Under the concentrations, which were within the optimum range for generating theta-like waves, LTP was most facilitated. In addition, the higher augmentation of LTP occurred when LTP was induced during the generation of theta-like wave. These results suggested that depending on the activity of the cholinergic septal input to hippocampus, different patterns of rhythmical waves are induced and the plasticity in hippocampal neural networks can be modulated by them.
