Central cholinergic descending pathway to the dorsal motor nucleus of the vagus in regulation of gastric functions.

A possible role of the cholinergic mechanism within the dorsal motor nucleus of the vagus (NDV) in the regulation of gastric functions was examined in urethane anesthetized rats. Pretreatment with atropine (1-5 nmole), intracerebroventricularly inhibited the increase in both gastric acid output and mucosal blood flow (MBF), as induced by electrical stimulation of the lateral hypothalamic area (LHA). Bethanechol, microinjected into the dorsal vagal complex (the NDV, the nucleus tractus solitarius and area postrema) induced dose-dependent (5-30 nmole) increases in gastric acid output and MBF, while nicotine was without effect. Pretreatment with atropine 3 nmole microinjected into the dorsal vagal complex completely blocked the increases induced by electrical stimulation of the LHA. Furthermore, the increases in these gastric parameters induced by the administration of 2-deoxy-D-glucose (2-DG) were also significantly inhibited by atropine microinjected into the dorsal vagal complex. These results suggest that neurotransmission of the central descending pathway to the NDV in excitatory regulation of gastric functions is probably mediated through cholinergic muscarinic receptors.