Comparative histochemical studies of adrenergic nerves in the enteric plexuses of vertebrate large intestine

Abstract

1. 1. A comparative fluorescent histochemical study of the localization of monoamines in the enteric plexuses of the large intestine of the guinea-pig, lizard, toad, trout and eel has been made. 2. 2. An extensive system of adrenergic nerves occurs in Auerbach's plexus of the toad, but there are neither fluorescent nerve cell bodies nor pericellular networks about nerve cells. 3. 3. In Auerbach's plexus of the lizard, catecholamine fluorescence is present in many nerve bundles, a few nerve cell bodies and some varicose nerve fibres encircling both fluorescent and nonfluorescent nerve cells. 4. 4. Both Auerbach's and Meissner's plexuses of the guinea-pig possess varicose noradrenergic nerve fibres in bundles and in pericellular networks about nonfluorescent ganglion cells at the nodes. 5. 5. Adrenergic nerve fibres in Auerbach's plexus of teleosts form a less extensive system than in higher vertebrates. 6. 6. It was concluded that the presence of noradrenergic terminals about ganglion cells in the enteric plexuses of mammals is a relatively recent evolutionary development.