AJP - Regulatory, Integrative and Comparative Physiology, Vol 263, Issue 2 331-R338, Copyright © 1992 by American Physiological Society
Neural regulation of the vas deferens in the rat: an electrophysiological analysis
S. C. Kolbeck and W. D. Steers
Department of Urology, University of Virginia Health Sciences Center, Charlottesville 22908.
Electrophysiological analysis of the neural control of the vas deferens was
performed in urethan-anesthetized rats. Intraluminal distension (0.2
ml/min) or electrical stimulation of hypogastric (threshold 1-5 V, 20 Hz)
and pelvic nerves (2-5 V, 20 Hz) produced contractions of the vas deferens.
Distension-evoked contractile activity was not abolished by nicotinic
ganglionic blockade or ipsilateral hypogastric and pelvic nerve
transection. Contractions following hypogastric nerve stimulation were
abolished by prazosin, while pelvic nerve-evoked responses were partially
blocked by atropine. Hypogastric nerve, pelvic nerve, and sympathetic chain
stimulation evoked volleys with latencies of 10-30 ms in vasal nerves.
Crude estimates for conduction velocities for these responses (less than
0.5 m/s) corresponded to activation of unmyelinated C-fibers. Stimulation
of the dorsal nerve of the penis (DNP) (10-16 V, 10-40 Hz) or
administration of 5-methoxy-N,N-dimethyltryptamine, both of which produce
seminal emission, elicited reflex discharges in nerves to the vas deferens.
Hypogastric nerve but not pelvic nerve transection abolished both
spontaneous and evoked (105- to 380-ms latency) reflex activity. These
experiments provide insight into the organization of afferents in the DNP
and efferents conveyed by autonomic pathways that regulate male
reproduction.
