An analysis of the peripheral effects of l-DOPA on autonomic nerve function.
1 The ability of intravenous L-DOPA to block sympathetic and parsympathetic nerves has been studied in cats and dogs pretreated with a monoamine oxidase inhibitor.2 L-DOPA inhibited positive chronotropic and pressor responses to dimethylphenylpiperazinium (DMPP) and McN-A-343 in dogs, and contractions of the nictitating membrane produced by these ganglion stimulants in cats.3 Responses of the cat nictitating membrane to preganglionic stimulation were inhibited by L-DOPA to a greater extent than those to postganglionic stimulation of the cervical sympathetic chain.4 In dogs, L-DOPA had no vagolytic action, but depressed vasoconstrictor responses elicited in the perfused hind-limb by electrical stimulation of the lumbar sympathetic chain.5 The degree of lumbar sympathetic chain inhibition correlated with the pressor response following L-DOPA, and both effects were prevented by prior decarboxylase inhibition.6 These results suggest that the decarboxylation products of L-DOPA do not impair parasympathetic nerve activity but depress sympathetic nerve function predominantly by inhibiting both muscarinic and nicotinic sites of sympathetic ganglia.
D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D002714:Chlorisondamine / Q000494:pharmacology; D004285:Dogs; D004347:Drug Interactions; D004558:Electric Stimulation; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006614:Hindlimb / Q000098:blood supply; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology; D009541:Nictitating Membrane / Q000502:physiology; D010477:Perfusion; D012039:Regional Blood Flow / Q000187:drug effects; D014630:Vagus Nerve / Q000502:physiology
D008774:Methylphenidate; D007980:Levodopa; D002714:Chlorisondamine; D006145:Guanethidine