Effects of phenylethanolamine N-methyltransferase inhibitors on rat brain catecholamine levels and body temperature.

Inhibitors of phenylethanolamine N-methyltransferase (PNMT) were found to reduce hypothalamic and brainstem epinephrine (Epi) content, as well as the body temperature of male Sprague-Dawley rats. In the drug-treated animals, the time course for reduction of body temperature was better correlated with the reduction in brainstem Epi content than with the reduction in hypothalamic Epi content. These results suggest that brainstem Epi neurons may be directly involved in the regulation of body temperature by activating the heat production center or by preventing heat loss.