title: Dopaminergic inhibition of sympathetic activity in the cat.
abstract: The influence of dopaminergic agonists on the spontaneous and evoked activity of the sympathetic postganglionic renal efferent fibres was studied in lightly anaesthetized cats (urethane, 600 mg/kg, ip). Apomorphine, bromocriptine and piribedil (0.2, 0.07 and 0.4 mg/kg iv, respectively) depressed the spontaneous activity of the renal nerve. Electrical stimulation (16 V, 0.3 ms, 2-128 Hz, 2 s) of the sciatic nerve elicited a burst of activity of the sympathetic efferents followed by a silent period. Apomorphine and piribedil (the same doses as above) prolonged the duration of the silent periods. All these effects of dopaminergic agonists were antagonized by haloperidol (0.05-0.1 mg/kg iv). The results suggest that administration of dopaminergic agonists leads to preponderance of inhibition in the somato-sympathetic reflex integration.
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001971:Bromocriptine / Q000494:pharmacology; D002415:Cats; D004298:Dopamine / Q000502:physiology*; D004525:Efferent Pathways / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D004594:Electrophysiology; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D007668:Kidney / Q000294:innervation; D008297:Male; D010891:Piribedil / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*
chemical_list: D001971:Bromocriptine; D010891:Piribedil; D006220:Haloperidol; D001058:Apomorphine; D004298:Dopamine