Published-Ahead-of-Print May 23, 2007, DOI:10.2164/jandrol.107.002618
Journal of Andrology, Vol. 28, No. 6, November/December 2007
Copyright © American Society of Andrology
DOI: 10.2164/jandrol.107.002618
The Response of the Corporal Tissue and Cavernosus Muscles to Urethral Stimulation: An Effect of Penile Buffeting of the Vaginal Introitus
AHMED SHAFIK*,
ALI A. SHAFIK*,
OLFAT EL SIBAI
AND
ISMAIL A. SHAFIK*
From the * Department of Surgery and Experimental
Research, Faculty of Medicine, Cairo University, Cairo, Egypt; and
Department of Surgery, Faculty of Medicine,
Menoufia University, Shebin El-Kom, Menofia, Egypt.
|
Correspondence to: Dr Ahmed Shafik, 2 Talaat Harb St, Cairo 11121, Egypt
(e-mail:
shafik{at}ahmedshafik.com). |
We investigated the hypothesis that urethral stimulation in humans induces
sexual response in the form of activation of the corporal tissue and
cavernosus muscles through a reflex mechanism. Electromyographic activity of
corpora cavernosa (CC), corpus spongiosum (CS), bulbocavernosus (BCM), and
ischiocavernosus (ICM) muscles was recorded in 43 healthy volunteers (24 men,
19 women; age, 37.7 ± 8.2 years) during urethral stimulation. The tests
were repeated after individual anesthetization of urethra, CC, CS, BCM, and
ICM. During stimulation of the distal urethra, slow wave variables of CC and
CS decreased while motor unit action potentials of BCM and ICM increased.
Urethral stimulation after individual anesthetization of urethra, CC, CS, BCM,
and ICM did not effect significant changes in these structures, but saline
administration did. Diminished electromyographic activity of CC and CS with
increased activity of BCM and ICM during distal urethral stimulation
presumably denotes sinusoidal muscle relaxation of CC and CS and cavernosus
muscles' contraction. Sinusoidal muscle relaxation and contraction of
cavernosus muscles upon distal urethral stimulation are suggested to be
mediated through a reflex that we call the "urethro-corporocavernosal
reflex." Sinusoidal and cavernosus muscles' response during coitus
appears to effect a degree of tumescence for both male and female
partners.
Key words: Corpora cavernosa, corpus spongiosum, ischiocavernosus/bulbocavernosus muscles, slow waves, electromyography
Copyright © 2007 by The American Society of Andrology.