Abstract
Spinal cord transection of rats at C-7 resulted in generally higher blood and liver concentrations of CCl4 over a 24-hour period than were observed in intact rats after a single oral dose of the agent. However, 24 hours after a single dose of CCl4 cordotomized rats did not exhibit the typical hepatic degenerative changes that were seen in intact rats. Instead, the lesion developed over a longer time course, becoming fully developed between 55 and 65 hours after treatment. Cordotomized rats rapidly became hypothermic following the surgery. Hypothermia induced by immersion of intact rats in water resulted in a protective effect comparable to cordotomy against CCl4. This method of inducing hypothermia also resulted in liver concentrations of CCl4 that followed a pattern similar to that seen after cordotomy.
Whole-body O2 consumption was reduced to about 50% of normal by 1 hour and to about 30% by 5 hours after cord transection. Depression of body temperature sufficient to account for these decreases was observed in this time. Water immersion also resulted in a markedly reduced rate of O2 consumption.
The infusion of high concentrations of norepinephrine, epinephrine or mixtures of the two for 20 hours did not induce a CCl4-like hepatic lesion nor a potentiation of CCl4 effects in cordotomized rats.
These results support the hypothesis that the protective effect of cervical cordotomy against CCl4-hepatotoxicity lies in the reduced hepatic metabolism produced by the hypothermia produced by the surgery.
Footnotes
- Accepted September 24, 1964.
- The Williams & Wilkins Comapny
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