Exposure to cadmium during gestation and lactation decreases cocaine self-administration in rats

This investigation examined the effects of perinatal cadmium exposure on subsequent self-administration of cocaine during the adult cycle. Female Sprague-Dawley rats were gavaged daily with 0.0 (14% sucrose solution, w/v) or 5.0 mg cadmium chloride (dissolved in 14% sucrose solution, w/v) for 30 days prior to breeding with non-exposed males. Dams continued to experience cadmium exposure through gestation and until pups were weaned at postnatal day (PND) 21. On PND 70, offspring were anesthetized and chronic indwelling jugular catheters were implanted. Following recovery, test subjects were trained in operant chambers to self-administer 0.500 mg/kg infusion (inf) intravenous cocaine on a fixed-ratio (FR) 2 schedule of reinforcement. Following acquisition, self-administration rates were tested for saline, 0.030, 0.060, 0.125, 0.250, and 0.500 mg/kg inf cocaine. Rats exposed developmentally to cadmium self-administered significantly less than controls at saline, 0.030, and 0.060 mg/kg inf cocaine. These data indicate that early-life cadmium exposure, a common exposure vector of which is the use of tobacco products, may affect cocaine sensitivity.