title: Evidence for the existence of prejunctional receptor sites for dopamine in the mouse vas deferens.
abstract: The present work is focused on the effects of newly developed dopaminergic agonists and antagonists on the field-stimulated vas deferens. Both LY 171555 and SK&F 38393, relatively selective DA2 and DA1 receptor agonists, respectively, produced concentration-dependent inhibition of the field stimulation-evoked contractions in the mouse vas deferens; both compounds did not modify the baseline tone nor the contractile responses to exogenous noradrenaline. Control LY 171555 and SK&F 38393 concentration-response curves, were shifted rightward in a parallel manner in the presence of sulpiride (relatively specific DA2 antagonist) and SCH 23390 (relatively specific DA1 antagonist), respectively. Control concentration-response curves for dopaminergic agonists were not modified in the presence of specific blockers for H1 and H2 histamine receptors, serotonin receptors and alpha 2-adrenoceptors. These preliminary findings are suggestive of the existence of two dopaminergic receptor types both presumably located prejunctionally.
authors: Institute of Pharmacology, Medical Faculty, University of Bari, Italy.
authors: M R
authors: MR
authors: Carratù
authors: D
authors: D
authors: Conte-Camerino
authors: A
authors: A
authors: De Serio
authors: E
authors: E
authors: Ferrari
authors: D
authors: D
authors: Mitolo-Chieppa
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000320:Adrenergic Fibers / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D004558:Electric Stimulation; D004873:Ergolines / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000294:innervation* / Q000502:physiology; D019257:Quinpirole; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D014649:Vas Deferens / Q000294:innervation* / Q000502:physiology
chemical_list: D004873:Ergolines; D011954:Receptors, Dopamine; D019257:Quinpirole; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D003000:Clonidine