Observations on the Smooth Muscle and Contractile Activity of the Common Bile Duct

Abstract

Anatomic and physiologic evidence is presented to show longitudinal smooth muscle fibers are present in the common bile duct of the Rhesus monkey, but not to the extent as that of the dog. Anatomic evidence of longitudinal smooth muscle in the human bile duct is also presented. Physiology and pharmacology prove that the smooth muscle of the monkey''s common bile duct is of the mus-cularis mucosae type. The autonomic innervation of the bile duct smooth muscle appears to contain ganglia which are stimulated by acetylcholine or McNeil-A-343 [4(m-chlorophenylcarbamoyloxy)-2-butynyltrimethylammonium chloride] blocked by atropine, and unaffected by hexamethonium. The predominant peripheral neuro-transmitter appears to be norepinephrine acting on an alpha receptor to produce contraction.