GESTATIONAL COCAINE EXPOSURE INCREASES OPIATE RECEPTOR-BINDING IN WEANLING OFFSPRING

The use of cocaine during pregnancy produces a variety of adverse effects in offspring. Gestational cocaine exposure is known to affect developing dopamine systems, but other neurochemical systems may also be at risk. Regional density of opiate receptors labeled with [H-3]naloxone was examined in the brains of 21-day-old male rats exposed to cocaine (0, 10, 20, or 40 mg/kg/day s.c.) between gestation days 8 and 20. Gestational cocaine exposure significantly increased labeling in a dose-dependent fashion in dopaminergic terminal (e.g. the nucleus accumbens, medial prefrontal cortex, olfactory tubercle, and caudatoputamen), limbic (e.g. basolateral amygdaloid nucleus, lateral habenula, hippocampus, dentate gyrus, entorhinal and cingulate cortices) and neocortical (e.g. somatosensory and motor cortices) regions, but had little effect in diencephalic or brainstem regions. The results suggest a functional linkage whereby drug-induced alteration of dopamine systems can regulate developing opioid systems in the brain. Moreover, gestational cocaine exposure produced long-lasting changes of opiate receptor labeling in certain brain regions. The implications of these results are uncertain. However, such effects on endogenous opioid systems could contribute to a developmental delay, cognitive or motor dysfunction.