Antagonism of acetaminophen-induced hepatocellular destruction by trifluoperazine in mice.

The effect of trifluoperazine, a specific calmodulin inhibitor, on hepatocellular destruction induced by acetaminophen was investigated in mice. Trifluoperazine 30 mg/kg administered intraperitoneally 30 min. or 0 min. before acetaminophen blocked hepatocellular destruction induced by the hepatotoxin, as evidenced by the determination of plasma GPT activity. Trifluoperazine also completely inhibited an increase of calcium contents in liver induced by acetaminophen administration. Furthermore, the increase of hepatic phosphorylase a activity induced by acetaminophen administration was completely abolished by pretreatment with trifluoperazine. However, hepatic glutathione depletion induced by acetaminophen was not prevented by pretreatment with trifluoperazine. Trifluoperazine administration caused a marked decrease in the body temperature of acetaminophen-treated animals. However, when the trifluoperazine-treated acetaminophen-poisoned animals were kept normothermic, the preventive effects were abolished. These findings suggest that this protective effect may be mediated by the trifluoperazine blockade of the deleterious effects of calcium accumulation in liver or the trifluoperazine decreasing effects on body temperature.