ORIGINS OF NERVE-TERMINALS CONTAINING NITRIC-OXIDE SYNTHASE IN THE GUINEA-PIG CELIAC GANGLION

Nitric oxide synthase was localised immunohistochemically and by NADPH diaphorase activity in two groups of nerve terminals and in rare cell bodies in the guinea-pig coeliac ganglion. Strongly reactive varicose terminals surrounded a subgroup of principal ganglion cells, most of which were in the medial lobes of the ganglion and most of which were somatostatin immunoreactive. A second set of varicose terminals, which were less intensely reactive, were found throughout the ganglia. Nitr ic oxide synthase containing nerve cell bodies in the intermediolatera l cell columns of the spinal cord were labelled by dye retrogradely tr ansported from the coeliac ganglion. Lesion of nerve connections betwe en abdominal viscera and the coeliac ganglion caused a loss of the str ongly reactive fibres, while the widely distributed, less intensely re active fibres persisted. It is concluded that nitric oxide synthase te rminals in the coeliac ganglion come from two sources, sympathetic pre ganglionic neurons and intestinofugal neurons.