Endotoxin-induced alterations in contractility of isolated blood vessels from sheep.
The present study examined reactivity to norepinephrine (NE) and KCl in isolated, suffused blood vessels from the systemic and pulmonary circulations of endotoxin-treated and control sheep. A possible mechanism underlying an endotoxin-induced alteration in vascular reactivity was also investigated. Chronically instrumented sheep were given Escherichia coli endotoxin (1.5 micrograms/kg). Eight to 12 h later these endotoxin-treated animals exhibited a significantly increased cardiac output and decreased systemic vascular pressure and resistance. The pulmonary vascular pressure and resistance were not changed. The isolated superficial femoral artery from the endotoxin sheep exhibited depressed contractions in response to KCl (75 mM) and to NE (10(-7)-10(-5) M), whereas the pulmonary artery (tertiary branch) did not exhibit altered reactivity. The decreased sensitivity to NE in the femoral artery from endotoxin sheep did not appear to involve an alteration of alpha- or beta-adrenoceptors, or an increased release of vasodilator prostanoids, or endothelium-derived relaxing factor.
Nelson
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Department of Anesthesiology, University of Texas Medical Branch, Galveston 77550.
Steward
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Traber
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D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001808:Blood Vessels / Q000187:drug effects* / Q000502:physiology; D002302:Cardiac Output / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000494:pharmacology*; D004926:Escherichia coli; D005260:Female; D005263:Femoral Artery / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology; D012756:Sheep; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects*
D004731:Endotoxins; D011943:Receptors, Adrenergic, beta; D011189:Potassium Chloride; D009638:Norepinephrine