Physiology & behavior
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Physiology & behavior · Mar 2005
Comparative StudyBrain and body temperature homeostasis during sodium pentobarbital anesthesia with and without body warming in rats.
High-speed, multi-site thermorecording offers the ability to follow the dynamics of heat production and flow in an organism. This approach was used to study brain-body temperature homeostasis during the development of general anesthesia induced by sodium pentobarbital (50 mg/kg, ip) in rats. Animals were chronically implanted with thermocouple probes in two brain areas, the abdominal cavity, and subcutaneously, and temperatures were measured during anesthesia both with and without (control) body warming. ⋯ These results suggest that pentobarbital-induced inhibition of brain metabolic activity is a major factor behind brain hypothermia and global body hypothermia during general anesthesia. These data also indicate that body warming is unable to fully compensate for anesthesia-induced brain hypothermia and enhances the negative brain-body temperature differentials typical of anesthesia. Since temperature strongly affects various underlying parameters of neuronal activity, these findings are important for electrophysiological studies performed in anesthetized animal preparations.