Differences in simultaneous cylic adenosine monophosphate concentrations of various rat tissue after heroin...

Opiate administration has profound effects on neurotransmitter metabolism and neuroendocrine functions. Since cAMP is an intracellular metabolite common to the actions of many of the involved compounds stimulating distinct and specific membrane receptors, cAMP concentrations representative of in vivo conditions in heroin-treated and control animals were determined. Rats were sacrificed by immersion in liquid nitrogen 30 min after heroin injection. Tissue samples, dissected without thawing, were assayed by radioimmunoassay to determine cAMP/mg of protein. Comparisons between treated animals and sham-injected controls revealed significant cAMP concentration increases in hypothalamus, cerebral cortex, cerebellum, adrenal medulla, adrenal cortex, and liver (P less than 0.0005). Cyclic AMP concentrations in heart, skeletal muscle, kidney, and fat were not significantly different from controls. The increased tissue cAMP concentrations associated with the altered physiology of heroin administration apparently represent a pattern of integrated responses to the combination of opiate receptor binding and effects on neurotransmitter metabolism and circulating hormones.