Effect of testosterone on the response of young rat vas deferens to norepinephrine.
1. Following in vitro treatment with 12 microM 6-hydroxy-dopamine, 2 microM B-oestradiol, 0.1 microM propranolol and 10 microM cocaine vasa deferentia isolated from young rats (21-23 days old) showed supersensitivity to norepinephrine (NE) compared to those from adult (3 months old) rats. 2. The pA2 values for prazosin were higher in young (9.6 +/- 0.1) than in adult (8.3 +/- 0.1) rat vas deferens, with the slopes of the Schild plots not different from 1.0 (0.78 +/- 0.26 and 1.14 +/- 0.14, respectively). 3. The treatment of young rats with a single dose of testosterone abolished the supersensitivity to NE and the higher affinity for prazosin. 4. We conclude that there is a reduction of neuronal NE uptake and a decrease in the sensitivity to NE in the vas deferens as the rat matures sexually. 5. Testosterone induces a decrease in the sensitivity to NE, probably via an action on the alpha 1-adrenoceptor population and the sympathetic nerve discharge in this organ.
Lamas
J L
JL
Departamento de Enfermagem, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brazil.
Spadari
R C
RC
D000818:Animals; D001464:Barium / Q000494:pharmacology; D017609:Barium Compounds; D002217:Carbachol / Q000494:pharmacology; D002712:Chlorides; D003042:Cocaine / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000494:pharmacology*; D014649:Vas Deferens / Q000187:drug effects
D017609:Barium Compounds; D002712:Chlorides; C024986:barium chloride; D001464:Barium; D013739:Testosterone; D004958:Estradiol; D002217:Carbachol; D011433:Propranolol; D003042:Cocaine; D009638:Norepinephrine; D011224:Prazosin