Central cholinergic synapses: the septohippocampal system as a model.

This chapter deals with the septohippocampal cholinergic projection in the rodent brain. A monoclonal antibody against choline acetyltransferase (ChAT) was used to label the cells of origin in the medial septum/diagonal band complex (MSDB) and cholinergic fibers and synapses in the hippocampal formation. The target neurons of septohippocampal cholinergic afferents were identified by combining immunocytochemistry with Golgi impregnation or by double immunolabeling. Types of cholinergic synapses very similar to those found in the hippocampal formation were also observed in other brain regions containing cholinergic neurons and terminals. This lends support to the view detailed in this chapter that the septohippocampal projection is a useful model for studies of cholinergic synaptic mechanisms in the CNS.