Cavernosal nerve stimulation in the rat reverses the castration
-induced decrease in penile nitric oxide synthase activity.
Lugg, James, Chris Ng, Jacob Rajfer, and N[acute]estor
Gonz[acute]alez-Cadavid.
Division of Urology, Department of Surgery, UCLA School of
Medicine, Harbor-UCLA Medical Center, Torrance, CA 90509
APStracts 3:0073E, 1996.
Castration in the rat reduces both the erectile response and penile
nitric oxide synthase (NOS) activity, and these effects are prevented
by androgen administration. In this study we have determined whether
the decrease of penile NOS in the castrated rat is due to NOS enzyme
inhibition rather than to a reduction of its content, and wheter this
inhibition may be reversed. Adult rats were either castrated or left
intact, and after one week electrical field stimulation (EFS) was
applied to the cavernosal nerve and the penises were excised either
at the peak of erection or after detumescence. Penile NOS activity in
the non-EFS castrates decreased by 70% as compared with the intact,
non-EFS treated controls, but neuronal NOS (nNOS) content remained
unaffected despite changes in regional distribution. NOS activity in
the castrate penis was restored to normal values by EFS at the peak
of stimulation, and then decreased upon detumescence. This was in
contrast to the intact controls where EFS did not stimulate penile
NOS activity. These data indicate that androgen depletion in the rat
reduces penile NOS activity rather than NOS content, and that this
enzyme inhibition is reversed by cavernosal nerve stimulation.
Received 13 November 1995; accepted in final form 18 March 1996.
APS Manuscript Number E540-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 April 96