2-MERCAPTOACETATE AND 2-DEOXY-D-GLUCOSE INDUCE FOS-LIKE IMMUNOREACTIVITY IN RAT-BRAIN

2-Deoxy-D-glucose (2-DG) and 2-mercaptoacetate (MA) are antimetabolic drugs that selectively antagonize glucose and fatty acid utilization, respectively, and stimulate feeding. Fos immunohistochemistry was empl oyed to identify brain neurons activated by these drugs and to assess the role of the vagus nerve in the drug effects. Remote intravenous in fusions of both MA and 2-DG induced Fos-like immunoreactivity (Fos-li) in specific brain sites, but the pattern was different for the two dr ugs. Mercaptoacetate induced Fos-li in the nucleus of the solitary tra ct (NTS), the central subnucleus of the lateral parabrachial nucleus ( IPBN), the central nucleus of the amygdala (CNA, lateral part) and the dorsal motor nucleus of the vagus (DMV). Induction of Fos-li in the b rain by MA was totally abolished by vagotomy. 2-Deoxy-D-glucose also i nduced Fos-li in the NTS, CNA (lateral part) and DMV, as well as in th e external IPBN subnucleus, locus coeruleus, paraventricular and supra optic hypothalamic nuclei, and in scattered cells throughout the dienc ephalon. Induction of Fos-li by 2-DG was not blocked by vagotomy. Resu lts suggest that 2-DG's effects on Fos-li are mediated by a direct cen tral action, whereas MA's effects are mediated by peripheral sensory n eurons. Thus, availability of glucose and fatty acids influences the a ctivity of specific brain sites by different neural mechanisms. The co rrelation of Fos-immunoreactive sites with sites where lesions have be en shown to cause deficits in MA- and 2-DG-induced feeding indicates t hat c-fos expression defines in part the central pathways involved in the metabolic control of feeding.