Different alpha1-adrenoceptor-induced inositol phosphate formation in the two portions of rat vas deferens.
The two portions of rat vas deferens differed in the postjunctional sensitivity to noradrenaline. Alpha1-adrenoceptor-linked phosphoinositide breakdown was analysed in this tissue. The noradrenaline-induced [3H]inositol phosphate accumulation was similar in both ends although the pEC50 was higher in the epididymal (5.97+/-0.07) than in the prostatic (5.47+/-0.15, P<0.01) portion. [3H]Prazosin showed similar density of binding sites in both portions. Tissue pretreated with pertussis toxin did not change [3H]inositol phosphate accumulation. Finally, Western blot analysis indicated a smaller concentration of Gq/11 protein in the prostatic half (-29+/-5%, P<0.01). These results suggest that the different sensitivity to noradrenaline could be due to the higher availability of this sort of G protein in the epididymal portion.
Terradas
D
D
Dpt Farmacologia i Terapèutica, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Tabernero
A
A
Badia
A
A
Vivas
N M
NM
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D004822:Epididymis / Q000187:drug effects / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000378:metabolism / Q000494:pharmacology; D011224:Prazosin / Q000378:metabolism / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D014316:Tritium; D014649:Vas Deferens / Q000187:drug effects / Q000378:metabolism*
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D007295:Inositol Phosphates; D018340:Receptors, Adrenergic, alpha-1; D014316:Tritium; D019204:GTP-Binding Proteins; D009638:Norepinephrine; D011224:Prazosin; D010646:Phentolamine