[Action of N-butylnorsympathone on the effects of cardioaccelerator nerve stimulation in the dog].
In Dogs anaesthetized with pentobarbital (30 mg . kg-1), N-butylnorsympathone (20 mg . kg-1 i.v.) reduced the bradycardia induced by stimulating the cardiac nerve (1, 2, 5, 10 Hz). Phentolamine (1 mg . kg-1 i.v.) or yohimbine (0.3 mg . kg-1 i.v.), two potent alpha-adrenoceptor blocking agents known to block presynaptic alpha-adrenoceptor induced a recovery of the effect of cardiac nerve stimulation. Prazosine (0.050 mg . kg-1 i.v.) an alpha-adrenoceptor blocking agent known to be ineffective on presynaptic alpha-adrenoceptors did not induce a recovery. However neither phentolamine or yohimbine were able to prevent the effects of N-butylnorsympathone. Neither haloperidol (0.050 to 2 mg . kg-1 i.v.) or pimozide (0.20 to 1 mg . kg-1 i.v.) induced a recovery or prevented the effects of N-butylnorsympathone. These results suggest that N-butylnorsympathone may stimulate presynaptic receptors which do not resemble classical presynaptic alpha-adrenoceptors or dopamine receptors.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D004558:Electric Stimulation; D004983:Ethanolamines / Q000494:pharmacology*; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D006329:Heart Conduction System / Q000187:drug effects / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011954:Receptors, Dopamine / Q000187:drug effects; D017981:Receptors, Neurotransmitter / Q000187:drug effects; D046948:Secologanin Tryptamine Alkaloids / Q000494:pharmacology
D004983:Ethanolamines; D011942:Receptors, Adrenergic, alpha; D011954:Receptors, Dopamine; D017981:Receptors, Neurotransmitter; D046948:Secologanin Tryptamine Alkaloids; D006220:Haloperidol; D011224:Prazosin; D010646:Phentolamine
Actions de la N-butylnorsympathone sur les effets de la stimulation du nerf cardioaccélérateur chez le chien.