title: Endotoxin-induced impairment of vasodepressor responses in the pithed rat.
abstract: The effects of Eschericia coli endotoxin on vascular responsiveness were compared with those of sodium nitroprusside in pithed rats. Infusion of endotoxin (250 micrograms kg-1 h-1) produced a fall in mean arterial blood pressure (11 mmHg) and impaired vasodepressor responses to endothelin, 5-hydroxytryptamine, acetylcholine, bradykinin, sodium nitroprusside and salbutamol. Prevention of endotoxin-induced hypotension with vasopressin infusion (0.64 i.u. kg-1 h-1 i.v.) restored responsiveness to bradykinin, tended to restore responsiveness to endothelin and sodium nitroprusside but failed to restore responsiveness to acetylcholine, 5-HT or salbutamol. Infusion of sodium nitroprusside at a rate (400 micrograms kg-1 h-1) producing a similar fall in blood pressure to that produced by endotoxin markedly impaired vasodepressor responsiveness to 5-HT. However, this was fully restored when the hypotension was prevented by vasopressin infusion. Vasodepressor responsiveness to either acetylcholine or salbutamol was not impaired by sodium nitroprusside in vasopressin-infused rats. The impairment of vasodepressor responsiveness by endotoxin is not due to endotoxin-induced hypotension and does not fit clearly with an endotoxin-mediated impairment of endothelial function.
authors.affiliation: Department of Physiology and Pharmacology, University of Strathclyde, Scotland, U.K.
authors.forename: M O
authors.initials: MO
authors.lastname: Guc
authors.forename: G A
authors.initials: GA
authors.lastname: Gray
authors.forename: B L
authors.initials: BL
authors.lastname: Furman
authors.forename: J R
authors.initials: JR
authors.lastname: Parratt
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001920:Bradykinin / Q000494:pharmacology; D016232:Endothelins / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology; D004731:Endotoxins / Q000009:adverse effects*; D004926:Escherichia coli; D007022:Hypotension / Q000139:chemically induced / Q000517:prevention & control; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology; D014667:Vasopressins / Q000627:therapeutic use
chemical_list: D016232:Endothelins; D004731:Endotoxins; D014667:Vasopressins; D009599:Nitroprusside; D012701:Serotonin; D000109:Acetylcholine; D001920:Bradykinin