The ramifications of adrenergic nerve terminals in the rectum, anal sphincter and anal accessory muscles of the guinea-pig

Abstract

The anatomy and the adrenergic innervation of the rectum, internal anal sphincter and of accessory structures are described for the guinea-pig. The distribution of adrenergic nerves was examined using the fluorescence histochemical technique applied to both sections and whole mount preparations. The longitudinal and circular muscle of the rectum and the muscularis mucosae are all supplied by adrenergic nerve terminals. The density of the adrenergic innervation of the muscularis externa increases towards the anal sphincter. There is a very dense innervation of the internal anal sphincter, of the anal accessory muscles and of the corrugator ani. Non-fluorescent neurons in the ganglia of the my..