Effect of dopamine-depleting brain lesions on suckling and weaning in rats.

Rats given large dopamine (DA)-depleting brain lesions as adults exhibit severe impairments in ingestive behavior and sensorimotor function. In contrast to these well-known effects, the present 2 studies showed that virtually complete destruction of central dopaminergic neurons produced no such dysfunctions when it occurred in neonates (Sprague-Dawley). Ss continued to suckle and grow, albeit somewhat more slowly, and they could be weaned readily when they were 27 days old. Although most brain-damaged Ss did not survive weaning when they were 18 days old (controls exhibited no difficulty), this failure appeared to be the consequence of their reduced body weight and related inability to maintain body temperature in a relatively cool environment (22°C). Such premature weaning occurred more successfully when growth was stimulated by rearing brain-damaged pups in small litters or when ambient temperatures were raised to 31°C to minimize heat loss. Results demonstrate that the effects of near-total DA-depleting brain lesions are considerably less severe when they occur in infants than when they occur in adults, and, consequently, they reveal a capacity for neural plasticity during development that is no longer present at maturity. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)