Endotoxin-induced impairment of vasodepressor responses in the pithed rat

M. Oguz Guc, Gillian A. Gray, Brian L. Furman, James R. Parratt

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The effects of Eschericia coli endotoxin on vascular responsiveness were compared with those of sodium nitroprusside in pithed rats. Infusion of endotoxin (250 μg kg-1 h-1) produced a fall in mean arterial blood pressure (11mmHg) and impaired vasodepressor responses to cndothclin, 5-hydroxytryptamine, acetylcholinc, bradykinin, sodium nitroprusside and salbutamol. Prevention of endotoxin-induced hypotension with vasopressin infusion (0.64 i.u. kg-1 h-1 i.v.) restored responsivencss to bradykinin, tended to restore responsivcncss to endothelin and sodium nitroprusside but failed to restore responsiveness to acetylcholinc, 5-HT or salbutamol. Infusion of sodium nitroprusside at a rate (400 μg kg-1h-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 rcsponsiveness by endotoxin is not due to endotoxin-induccd hypotension and does not fit clearly with an endotoxin-mediated impairment of endothelial function.

Original languageEnglish
Pages (from-to)63-70
Number of pages8
JournalEuropean Journal of Pharmacology
Issue number1
Publication statusPublished - Oct 29 1991



  • Endotoxin
  • Nitroprusside (sodium)
  • Vascular reactivity
  • Vasodilators

ASJC Scopus subject areas

  • Pharmacology

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