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Comparison between tamsulosin and alfuzosin on the expulsion phase of ejaculation in rats
Author(s) -
Giuliano François A.,
Clément Pierre,
Denys Pierre,
Alexandre Laurent,
Bernabé Jacques
Publication year - 2006
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/j.1464-410x.2006.06426.x
Subject(s) - tamsulosin , alfuzosin , medicine , ejaculation , agonist , cannula , urology , anesthesia , lower urinary tract symptoms , prostate , surgery , receptor , hyperplasia , cancer
OBJECTIVE To investigate the effects of acute intravenous (i.v.) delivery of tamsulosin and alfuzosin on the contractions of bulbospongiosus muscles (BS) induced by central delivery of a serotonin agonist, 8‐hydroxy‐2‐(di‐n‐propylamino)tetralin (8‐OH‐DPAT), in anaesthetized rats, as an experimental model of the expulsion phase of ejaculation. MATERIALS AND METHODS Under urethane anaesthesia, adult male rats were implanted with a cannula into the lateral cerebral ventricle for intracerebroventricular (i.c.v.) injection, and with recording electrodes in the BS for electromyogram (EMG) monitoring. Tamsulosin (1 µg/kg) and alfusozin (10 µg/kg) were injected i.v. and 15 min later 8‐OH‐DPAT (20 µg) was delivered i.c.v. BS‐EMG recording was continued for 30 min after i.c.v. 8‐OH‐DPAT. The area under the curve (AUC) of the BS cluster of contractions was determined as reflecting the energy of BS contractions. RESULTS After i.c.v. delivery of 8‐OH‐DPAT, there were rhythmic BS contractions in the form of clusters of bursts in vehicle‐, tamsulosin‐ and alfuzosin‐treated rats. The number of BS clusters was not altered by the α 1 ‐blockers as compared with vehicle, but the AUC was significantly less in tamsulosin‐treated rats than in vehicle‐ or alfuzosin‐treated (both P < 0.05) rats. CONCLUSION Systemic injection of tamsulosin impaired BS contractile capacity whereas alfuzosin did not. This might explain anejaculation in men treated with tamsulosin.