Facilitatory effect of nicotine on adrenergic neuroeffector transmission in the isolated ear artery of the rabbit.
The effects of nicotine were studied on perfusion pressure and vasoconstrictor responses to sympathetic nerve stimulation in the isolated ear artery of the rabbit. Infusions of nicotine (50 micro M) produced a transient increase in perfusion pressure and potentiated responses to nerve stimulation; these effects of nicotine were unaffected by atropine (0.3 micro M) and abolished or significantly reduced respectively by hexamethonium (300 micro M) or mecamylamine (1 micro M). In experiments with ear arteries previously labelled with [3H] noradrenaline an infusion of nicotine (50 micro M) produced a transient increase in tritium efflux and the potentiation of responses to nerve stimulation in the presence of nicotine was accompanied by a statistically significant increase in stimulation-induced tritium efflux; these effects of nicotine were abolished by hexamethonium (300 micro M) or mecamylamine (1 micro M).
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000294:innervation; D001285:Atropine / Q000494:pharmacology; D004347:Drug Interactions; D004423:Ear / Q000098:blood supply; D006584:Hexamethonium Compounds / Q000494:pharmacology; D066298:In Vitro Techniques; D008464:Mecamylamine / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009451:Neuroeffector Junction / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D014662:Vasoconstrictor Agents
D006584:Hexamethonium Compounds; D014662:Vasoconstrictor Agents; D008464:Mecamylamine; D009538:Nicotine; D001285:Atropine