Dopamine-induced neurogenic vasodilatation in isolated perfused muscle preparation of the dog.
Dopamine, injected into the lumbar aorta of the dog in doses which produce a reversible inhibition of synaptic transmission in the lumbar paravertebral ganglia (0.5-64x10-8 moles), produces a neurogenic vasodilatation in the isolated perfused hindleg or gracilis muscle. This was abolished by acute preganglionic decentralization and by administration into the perfused preparation of alpha-adrenoceptor blocking agents, but not of atropine or diphenhydramine. After decentralization, preganglionic electrical stimulation restored the dopamine-induced indirect vasodilatation. The neurogenic vasodilatation was also seen with intra-aortic injections of epinine (2-32x10-8 moles) and apomorphine (1.2-19.2x10-8 moles) and was preferentially blocked by haloperidol (0.26x10-6 moles). (-)-Noradrenaline, injected into the lumbar aorta in baroreceptor-denervated dogs, was found to be equipotent with dopamine in eliciting the neurogenic vasodilatation; this (-)-noradrenaline-induced effect was preferentially blocked by phentolamine (8x10-6 moles). The possibility that the neurogenic vasodilatation, which occurs upon intra-aortic injection of dopamine in the dog, is due to its gnaglionic-inhibitory effect is discussed.
D000109:Acetylcholine / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D001339:Autonomic Fibers, Preganglionic / Q000502:physiology; D001808:Blood Vessels / Q000187:drug effects*; D004155:Diphenhydramine / Q000494:pharmacology; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology*; D018492:Dopamine Antagonists; D005260:Female; D005725:Ganglia, Autonomic / Q000187:drug effects*; D006220:Haloperidol / Q000494:pharmacology; D006614:Hindlimb / Q000098:blood supply; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D009132:Muscles / Q000098:blood supply; D010477:Perfusion; D010646:Phentolamine / Q000494:pharmacology; D012018:Reflex / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D018492:Dopamine Antagonists; D007980:Levodopa; D001285:Atropine; D006632:Histamine; D004155:Diphenhydramine; D006220:Haloperidol; D001058:Apomorphine; D000109:Acetylcholine; D004298:Dopamine; D010646:Phentolamine