title: Comparison between tamsulosin and alfuzosin on the expulsion phase of ejaculation in rats.
abstract: 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.
  
  
  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 microg/kg) and alfusozin (10 microg/kg) were injected i.v. and 15 min later 8-OH-DPAT (20 microg) 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 alpha1-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.
  
  
  CONCLUSIONS
  Systemic injection of tamsulosin impaired BS contractile capacity whereas alfuzosin did not. This might explain anejaculation in men treated with tamsulosin.
authors.affiliation: Pelvipharm Laboratories, CNRS, Gif-sur-Yvette, France. giuliano@cyber-sante.org
authors.forename: François A
authors.initials: FA
authors.lastname: Giuliano
authors.forename: Pierre
authors.initials: P
authors.lastname: Clément
authors.forename: Pierre
authors.initials: P
authors.lastname: Denys
authors.forename: Laurent
authors.initials: L
authors.lastname: Alexandre
authors.forename: Jacques
authors.initials: J
authors.lastname: Bernabé
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000008:administration & dosage; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D004542:Ejaculation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D011799:Quinazolines / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017366:Serotonin Receptor Agonists / Q000008:administration & dosage; D013449:Sulfonamides / Q000494:pharmacology*; D000077409:Tamsulosin
chemical_list: D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; D017366:Serotonin Receptor Agonists; D013449:Sulfonamides; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; C047638:alfuzosin; D000077409:Tamsulosin