Ethanol consumption and free operant avoidance performance following exposure to dietary lead

Rats were exposed ad libitum to a diet containing either 500 ppm lead (Group Lead-Diet) or a control diet with no added lead (Group Control-Diet). On Day 60 both groups were presented with a 15% ethanol solution (nonchoice test) in the home cage for five days prior to placement on a choice test that presented animals with a 10% ethanol solution and tap water. Concurrently with the choice test in the home cage, animals were placed in operant chambers for one hr (pre-avoidance) prior to a 30 min free operant avoidance session (avoidance) and remained there for one hr (post-avoidance) after training. Throughout avoidance training, the choice test was conducted in the chamber as well as the home cage. In addition to evidence of greater ethanol consumption by Group Lead-Diet rats, the results showed that these animals lever pressed more frequently, but not more efficiently, than Group Control-Diet animals.