title: Centrally induced impairment of the hypotensive effects of R 28935 and R 29814 by prazosin in anaesthetized cats.
abstract: Prazosin (3 micrograms/kg) infused prior to erythro-1-(1-[2-(1,4-benzodioxan-2-yl)-2-hydroxyethyl]-4-piperidyl)-2-benzimidazolinone (R 28935) into the left vertebral artery (v.a.) of chloralose-anaesthetized cats diminished the hypotensive response to R 28935 (3 micrograms/kg, v.a.). A similar i.v. treatment did not alter the central hypotensive effect of R 28935 (micrograms/kg, v.a.). After prazosin (3 micrograms/kg, v.a.) there was a parallel shift to the right of the dose-response curve of R 28935 (v.a.). The central hypotensive effect of the threo isomer (R 29814; 30 micrograms/kg) was also diminished by the previous administration of prazosin (3 micrograms/kg, v.a.). These results indicate the involvement of central alpha 1-adrenoceptors in the mechanism of action of R 28935 and R 29814.
mesh_terms: D000758:Anesthesia; D000818:Animals; D000959:Antihypertensive Agents / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D001562:Benzimidazoles / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D002490:Central Nervous System / Q000187:drug effects*; D004146:Dioxanes / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D004147:Dioxins / Q000037:antagonists & inhibitors*; D004347:Drug Interactions; D005260:Female; D007275:Injections, Intravenous; D008297:Male; D011224:Prazosin / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D001562:Benzimidazoles; D004146:Dioxanes; D004147:Dioxins; D011799:Quinazolines; C010402:R 28935; D011224:Prazosin