Existence of dopamine D1 receptor on the sympathetic nerve endings in the guinea-pig vas deferens.
The effects of selective dopamine receptor agonists and antagonists on sympathetic neuromuscular transmission were investigated in the guinea-pig vas deferens in order to test for the presence of presynaptic dopamine receptors. A single-pulse field stimulus induced a rapid monophasic contraction which was strongly inhibited by alpha,beta-methylene ATP, a P2X purinoceptor desensitizing agent. The contraction was also inhibited by 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine (UK 14,304), a selective alpha2-adrenoceptor agonist. This inhibition was antagonized by idazoxan, an alpha2-adrenoceptor antagonist, but not by R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzaz epine hydrochloride (SCH-23390), a dopamine D1 receptor antagonist. Furthermore, the contractions were inhibited in a dose-dependent manner by R(+)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride (SKF-38393) and (+/-)-6-chloro-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-be nzazepine hydrobromide (SKF-82958), dopamine D1 receptor agonists, and the inhibition was antagonized by both SCH-23390 and idazoxan, but not by spiperone, a dopamine D2 receptor antagonist. The results suggest that dopamine D1 receptors are located on the sympathetic nerve endings of guinea-pig vas deferens.
Furukawa
T
T
Department of Pharmacology, School of Medicine, Fukuoka University, Japan.
Morishita
H
H
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D000068438:Brimonidine Tartrate; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004558:Electric Stimulation; D006168:Guinea Pigs; D019329:Idazoxan / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D017729:Presynaptic Terminals / Q000187:drug effects*; D011810:Quinoxalines / Q000494:pharmacology; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000187:drug effects*; D013134:Spiperone / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects*; D014649:Vas Deferens / Q000187:drug effects*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D001552:Benzazepines; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D011810:Quinoxalines; D017447:Receptors, Dopamine D1; D000068438:Brimonidine Tartrate; D013134:Spiperone; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; C071262:SK&F 82958; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D019329:Idazoxan