The intrinsic and vagal extrinsic innervation of the rat stomach contains nitric oxide synthase.

Nitric oxide synthase (NOS) associated with the intrinsic and vagal extrinsic innervation of the rat gastric corpus was studied in both control and neonatally capsaicin-treated animals. Nerve cell bodies and fibres of both the myenteric and sub-mucosal plexi of the gastric corpus was found to contain NOS, but were distinct from those containing VIP. NOS-positive fibres were seen innervating the circular smooth muscle layer. Stain accumulated both proximal and distal to a vagal ligature. Staining of the nucleus of the solitary tract (NTS) was associated with specific sub-nuclei. Neonatal capsaicin treatment did not alter the staining in the NTS, vagus nerve or stomach. The data presented here support the idea that NO is a non-adrenergic non-cholinergic transmitter associated with gastric function.