Perinatal undernutrition alters different neuronal systems that may account for changes in the reactivity to different pharmacological treatments. In this regards, previous reports from our laboratory have demonstrated an increased sensitivity to the stimulanting effects of amphetamine and cocaine in deprived rats as compared to controls. In order to evaluate the effect of early malnutrition on the rewarding properties of cocaine and morphine, we assessed such reinforcing effects employing the Conditioned Place Preference (CPP) paradigm. Dose-response curves to different doses of cocaine (5, 10 or 15 mg/kg i.p. daily injections during 4 days) showed a higher rewarding effect in deprived rats as compared to controls. Furthermore, a daily dose of 3 mg/kg of morphine during 3 days elicited similar rewarding response in both deprived and control rats. Meanwhile, a dose of 1.5 mg/kg evidenced a trend of rewarding effect only in deprived animals.
These preliminary results suggest that early undernutrition resulted in a higher reactivity to the reinforcing effects of these addictive drugs.
