Perinatal cocaine exposure and functional brainstem development in the rat.

Rat pups exposed to cocaine via maternal intromission throughout gestation and lactation displayed significantly prolonged auditory brainstem response component latencies and interwave intervals. Longitudinal analysis revealed that this effect was most pronounced on the 22nd postnatal day. Increasing the rate of stimulation further impaired neurosensory transmission in the caudal auditory pathway. These results indicate that both axonal and synaptic events may be affected to some degree and the timing (age) of optimum cocaine influence suggests that delayed myelination may be involved. The corresponding retardation in general development of the cocaine exposed pups further implicates maternal, fetal and postnatal utilization of nutritional resources as the basis for this outcome.