title: Effects of adrenoceptor agonists and antagonists on the firing of neurons in the rat A1 noradrenergic region.
abstract: Noradrenaline (NA), but not clonidine applied microiontophoretically, inhibited the firing of neurons in the rat A1 noradrenergic region, whereas intravenous clonidine dose-dependently inhibited their firing (ED50 = 18.3 micrograms/kg). The NA-induced inhibition was blocked by the beta-antagonist timolol, but not by the alpha-antagonists phentolamine or piperoxane. These results suggest that neurons in the A1 region possess beta-adrenoceptors rather than alpha-adrenoceptors near their cell bodies, and that systemically administered clonidine acts indirectly on these cells.
mesh_terms: D000322:Adrenergic Agonists / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D005260:Female; D006892:Hydroxydopamines / Q000494:pharmacology; D008526:Medulla Oblongata / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009433:Neural Inhibition; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology / Q000502:physiology*; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D013564:Sympathetic Nervous System / Q000166:cytology / Q000502:physiology*; D013565:Sympatholytics / Q000494:pharmacology*
chemical_list: D000322:Adrenergic Agonists; D006892:Hydroxydopamines; D013565:Sympatholytics; D016627:Oxidopamine; D003000:Clonidine; D009638:Norepinephrine