EFFECTS OF NALOXONE AND MORPHINE IN HEMORRHAGIC-SHOCK

  • 1 January 1982
    • journal article
    • research article
    • Vol. 9  (4) , 375-382
Abstract
The effects of naloxone hydrochloride and morphine sulfate on survival were examined in LD40 [40% lethal dose] hemorrhagic shock in rats. Bolus i.v. injection of naloxone (1.6 mg/kg) following hemorrhage significantly (P < 0.025) increased the 24-h survival rate (14/15, 93%), compared to that in saline-treated animals (13/22, 59%). Supraphysiologic doses of i.v. morphine sulfate did not adversely influence survival (12/15, 80% at 0.5 mg/kg; 8/15, 53% at 0.1, 0.05 and 0.01 mg/kg). Morphine decreased heart rate during shock in a dose-dependent fashion but did not affect the blood pressure. Compared to responses in the other groups, naloxone had no effect on blood pressure or heart rate in shock animals during the monitoring interval. Endogenous opioid substances, most likely at much lower blood concentrations than those used in the present experiment, may not be important deleterious factors during shock, and enhancement of survival by naloxone in hemorrhagic shock is probably due to effects other than antiopiate activity.