title: Chronic nicotine treatment enhances the depressor responses to arachidonic acid in the rat.
abstract: The depressor responses to intravenous injections of arachidonic acid, prostacyclin (PGI2), prostaglandin E2 (PGE2) and sodium nitroprusside were studied in chronically nicotine-treated rats. Arachidonic acid, PGI2, PGE2 and sodium nitroprusside decreased the diastolic blood pressure dose-dependently in the control animals. The vasodepressor effect of arachidonic acid was significantly enhanced in rats given nicotine 5 and 25 micrograms/ml in their drinking water for 10 days but remained unchanged in the animals treated with 1 microgram/ml nicotine for 10 days or given 1 mg/kg i.v. nicotine 10 min before administration of arachidonic acid. Indometacin abolished arachidonic-acid-induced depressor responses in both the control and nicotine-treated rats. Hypotension induced by PGI2, PGE2 and sodium nitroprusside was of similar magnitude in the control and nicotine-treated animals. It is suggested that the enhancement by chronic nicotine treatment of depressor responses to arachidonic acid could be due to changes in the formation and/or removal of its vaso-active metabolites (i.e. prostacyclin and/or thromboxane A2).
authors.affiliation: Department of Pharmacology, Faculty of Medicine, University of Hong Kong.
authors.forename: S C
authors.initials: SC
authors.lastname: Hui
authors.forename: C W
authors.initials: CW
authors.lastname: Ogle
mesh_terms: D000284:Administration, Oral; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D015232:Dinoprostone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D011464:Epoprostenol / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007275:Injections, Intravenous; D008297:Male; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D001095:Arachidonic Acids; D009599:Nitroprusside; D016718:Arachidonic Acid; D009538:Nicotine; D011464:Epoprostenol; D015232:Dinoprostone; D007213:Indomethacin