The rat dorsal vagal nucleus: features of cellular and synaptic structure.

Using the stereological, histochemical and electron microscopic approaches the cellular and synaptic structure of the rat dorsal vagal nucleus (DVN) were studied. Cellular organization of the DVN does not allow to distinguish any separate subnuclei but a conspicuous population of mainly small neurons in rostral extension of its lateral part lacking AChE activity. DVN neurons with high and moderate AChE activities are manifest on the 5th postnatal day. Their number increases on the 7th day. In this critical period of the brain sexual differentiation, a sexual dimorphism was observed in the activity of DVN cholinergic neurons. The electron microscopic studies showed a wide variety of the DVN synaptic patterns. In the rat DVN were found complicated synaptic structures resembling glomeruli. Two types of synaptic glomeruli are distinguished. The results suggest that DVN can be regarded as a sex-dependent brain area involved in a high level of information processing.