Alpha 1- and alpha 2-adrenoceptors in the smooth muscle of male and female rabbit urethra.
[3H]Prazosin and [3H]rauwolscine, specific alpha 1- and alpha 2-antagonists respectively, were used to label alpha-adrenoceptors in membranes from male and female rabbit urethra. In the male rabbit, [3H]prazosin bound with high affinity (Kd = 0.56 nM) to a single population of sites with a capacity of 73 fmol/mg protein. [3H]Rauwolscine bound with a lower affinity (Kd = 2.24 nM) to another single class of sites with a capacity of 41 fmol/mg protein. The order of potencies of various adrenergic compounds in inhibiting radioligand binding suggested that [3H]prazosin and [3H]rauwolscine interacted in the urethra with sites having the characteristics of alpha 1- and alpha 2-adrenoceptors, respectively. In addition, studies on the female rabbit urethra showed that alpha 2-adrenoceptor density and affinity were respectively 6 times higher and 2 times lower than in the male. No significant sex difference was observed for urethral alpha 1-adrenoceptors.
Yablonsky
F
F
Riffaud
J P
JP
Lacolle
J Y
JY
Dausse
J P
JP
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008566:Membranes / Q000378:metabolism; D009130:Muscle, Smooth / Q000378:metabolism*; D011224:Prazosin / Q000494:pharmacology; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D012737:Sex Factors; D014521:Urethra / Q000378:metabolism*; D015016:Yohimbine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D011224:Prazosin