| Cocaine abuse by women is correlated with a high incidence of child neglect and abuse, and young children prenatally exposed to cocaine show early signs of neurobehavioral stress, including excessive and high-pitched crying, increased state lability, decreased responsiveness to caregivers, stress-related behavioral differences, and poor social development. Research on the effects of in utero cocaine exposure on early brain development and behaviors that elicit maternal care is relatively sparse. Using a rat model of cocaine-induced maternal neglect, the goals of this dissertation were to first examine the impact of cocaine on the interactions between rodent mothers and pups and to determine whether specific elements of pup behavior may be altered by prenatal cocaine exposure to influence these interactions. The first experiment described here examined whether the effects of cocaine-induced maternal neglect extend intergenerationally and if the rearing environment (neglectful or nurturing) can alter the effects of prenatal cocaine on offspring. Results from this study indicated that cocaine-exposed pups elicited reduced maternal care from their rearing mother, regardless of that mother's drug history. Since rodent mothers attend to the specific stimuli of pups, such as vocalizations, body temperature, and olfactory cues, the next study was completed to examine the impact of cocaine on the cues utilized by pups to elicit care. Results from these studies suggested that prenatal cocaine-exposure influences thermoregulation and vocalization in the early postnatal period, either directly or perhaps in combination with the indirect effects of prenatal stress and malnutrition. A third experiment was also conducted to examine a number of chemicals in pup urine that may contribute to the elicitation of maternal care. The only chemicals of interest that were detectable in urine were cocaine and its major metabolites, found in samples through postnatal day 3, suggesting that cocaine may still be pharmacologically relevant into the postpartum period and may influence the taste and smell of pup urine, thus potentially influencing the maternal response. Together, this dissertation suggests that cocaine impacts both members of the mother-infant dyad to alter these important social interactions, and highlights numerous targets of prenatal cocaine on infant behavior for further study. |
