J Korean Androl Soc.  1993 Jun;11(1):55-61.

Role of nitric oxide and vasoactive intestinal peptide in the relaxation of the smooth muscle of the rabbit corpus cavernosum

• Park KS
• Lee JE
• Ryu SB

Abstract

Nitric oxide(NO) and vasoactive intestinal peptide(VIP) are being studied increasingly as nonadrenergic noncholinergic neurotransmitters in the smooth muscle of the corpus cavernosum. Isolated strips of rabbit corpus cavernosum were suspended in an organ bath to record their changes in isometric tension. They were precontracted with phenylephrine, and the responses to electric filed stimulation and to drugs such as acetylcholine and VIP were examined. Electric stimulation caused a frequency-dependent relaxation, which was significantly inhibited in the presence of N-nitro-L-arginine methyl ester(L-NAME) or methylene blue. The inhibitory effect of L-NAME was reversed by the addition of excess L-arginine. VIP fragment 1-12 significantly attenuated the relaxation response to electric stimulation and abolished the residual relaxation response in the presence of L-NAME. VIP elicited a concentration-dependent relaxation of the corpus cavernosum, which was not affected by L-NAME but was abolished by VIP fragment 1-12. Guanethidine, atropine, or indomethacin was without effect on the relaxation elicited by the electric field stimulation. These results suggest that relaxation of the corpus cavernosum is mediated by NO and VIP, with the two agents having additive effects.

MeSH Terms

Acetylcholine
Arginine
Atropine
Baths
Electric Stimulation
Guanethidine
Indomethacin
Male
Methylene Blue
Muscle, Smooth*
Neurotransmitter Agents
NG-Nitroarginine Methyl Ester
Nitric Oxide*
Penile Erection
Phenylephrine
Relaxation*
Vasoactive Intestinal Peptide*
Acetylcholine
Arginine
Atropine
Guanethidine
Indomethacin
Methylene Blue
NG-Nitroarginine Methyl Ester
Neurotransmitter Agents
Nitric Oxide
Phenylephrine
Vasoactive Intestinal Peptide