DOPAMINERGIC AND PEPTIDERGIC MESSENGER-RNA LEVELS IN JUVENILE RAT-BRAIN AFTER PRENATAL COCAINE TREATMENT

The effects of prenatal cocaine treatment on gene expression in dopami nergic pathways of juvenile rats were investigated by in situ hybridiz ation histochemistry. Pregnant rats from gestational day. 8 to 20 were administered one of the following treatments: (A) 40 mg/kg cocaine hy drochloride/3 ml/day s.c.; (B) 0.9% saline/3ml/day s.c. and pair fed t o cocaine-exposed dams; (C) O.9% saline/3 ml/day s.c. and placement on cellulose-diluted diet to match the caloric intake of the cocaine-tre ated group without explicit food restriction; (D) no injection and lab chow diet. Levels of mRNA for the dopamine transporter, tyrosine hydr oxylase, cholecystokinin, D-1 and D-2 dopamine receptors and enkephali n were quantitated in relevant dopaminergic regions of forebrain and m idbrain of offspring that were sacrificed on postnatal day 21. Quantit ative analysis revealed no significant changes in mRNA levels in any o f the brain regions examined. In the present animal model, cocaine exp osure in utero had no significant effect on mRNA levels of the dopamin e transporter, D-1 or D-2 dopamine receptors, enkephalin, tyrosine hyd roxylase, or cholecystokinin in juvenile rats.