Inhibitory effect of sildenafil on the human isolated seminal vesicle.
OBJECTIVE
To investigate the effects of sildenafil on noradrenaline- and potassium-induced contractions of isolated human seminal vesicles (SVs), as premature ejaculation is a relatively common male sexual dysfunction that currently lacks an adequate therapy, and recent in vitro tests showed that sildenafil induces relaxation of rodent isolated SVs, but it is not known whether it also inhibits isolated human SV.


METHODS
Isolated strips of human SVs were suspended in an organ bath and cumulative concentration-response curves to either noradrenaline or KCl were constructed in the presence and absence of sildenafil to evaluate its inhibitory actions.


RESULTS
Sildenafil (25-100 microm) induced concentration-dependent inhibitory effects on the human SV contracted by either noradrenaline or KCl. These actions of sildenafil do not therefore appear to be mediated via a competitive antagonism of alpha-adrenoceptors and are consistent with its recognized ability to inhibit phosphodiesterase-5.


CONCLUSIONS
The present results show an important inhibitory action of sildenafil in the isolated human SV, supporting the therapeutic indication of this drug for treating premature ejaculation.
Gajar
Sessin A
SA
Service of Urology, State University of Rio de Janeiro, Brazil.
Tano
Tania
T
Resende
Angela C
AC
Bitencourt
José Augusto F
JA
de Lemos Neto
Miguel
M
Damião
Ronaldo
R
Criddle
David N
DN
Soares de Moura
Roberto
R
D000368:Aged; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011189:Potassium Chloride / Q000378:metabolism; D011687:Purines / Q000494:pharmacology; D012669:Seminal Vesicles / Q000187:drug effects* / Q000502:physiology; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000494:pharmacology*
D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D011189:Potassium Chloride; D000068677:Sildenafil Citrate; D009638:Norepinephrine