MORPHOLOGICAL-STUDY OF VAGAL INNERVATION IN HUMAN SEMILUNAR VALVES USING A HISTOCHEMICAL METHOD

To determine the innervation of human semilunar valves, we examined th e pulmonary and aortic valves of the normal autopsied hearts of 3 men (53 to 71 years old). Whole valve tissues with the aorta or pulmonary trunk were stained for acetylcholinesterase by a histochemical method. Acetylcholinesterase-positive nerve fibers with a diameter of 2 to 20 mm were located on the ventricular side of the semilunar valves. Inne rvation of the semilunar valves was extremely sparse compared with tha t of the atrioventricular valves and that of the aortic or pulmonary a rterial wall. The nerves originated from the subendocardium of the ven tricles and the adventitia of the arterial walls. The nerves were more distributed in the basal site than in the marginal site of the semilu nar valve. The nerve fibers formed a network in the basal two-thirds o f the leaflet. Thick nerves ramified in the thin nerve plexus. The thi ck nerves had a varicose-like structure. Thin nerves had a dot- and br ush-like ending. The nerves in human semilunar valves may play a role in valve motion.