COCAINE SELF-ADMINISTRATION ALTERS BRAIN NADH DEHYDROGENASE MESSENGER-RNA LEVELS

USING differential display PCR, we identified a cDNA whose expression is altered in several brain regions in rats self-administering cocaine . The cDNA sequence corresponds to bases 13687-13723 of the rat NADH d ehydrogenase subunit 6 gene. Northern analysis indicated a 26% decreas e in nucleus accumbens, a 305% increase in the ventral midbrain and no changes in the caudate putamen mRNA levels; changes were also noted i n the hypothalamus and cerebellum. This is the first demonstration of an effect of cocaine self-administration on mitochondrial gene express ion and suggests that regional metabolic changes elicited by cocaine m ay be relevant to and involved in its reinforcing properties.