It is estimated that 35-39 percent of mothers with young children experience depressive symptoms. Depression is associated with impaired maternal-infant interactions and children of depressed mothers exhibit increased behavioral and psychological problems. Confounding variables such as increased rates of marital discord and environmental stress make it difficult to infer a causal relationship between maternal behavior and outcome in offspring. A simplified model, using recently parturient rats, may be useful in identifying key behaviors. Animal studies have shown that maternal behavior and other early life experiences are critical in determining physiological and behavioral responses in the offspring. Despite the higher incidence of depressive symptoms in women than men virtually all animal studies modeling relevant behaviors have concentrated on males. Inescapable shock produces behavioral deficits in animals that are believed by many to be analogous to behavioral deficits in depressed patients. In the single extant study of newly parturient rats, impaired maternal behavior for 72 hours was reported. The purpose of this project is to study the effects of a single session of uncontrollable shock on newly parturient rat dams. Observations will be made of dam and pup behaviors. We will determine if exposure to inescapable shock produces alterations in maternal-infant interactions that extend beyond 72 hours post-shock. Dams will be exposed to uncontrollable shock, controllable shock or no shock conditions on post-natal day 2. Observations will begin the first day after birth, before the shock treatment is administered, and will continue for 10 days following shock exposure. We will also ascertain if pups reared by dams exposed to inescapable shock exhibit behavioral deficits when exposed to a challenging environment outside the home cage. Ultrasonic vocalization in response to social isolation will be measured and the amount of time the pup is immobile during a forced swim test on post-natal day 12. Finally, the hypothesis will be tested that identifiable differences in maternal behavior correlate with behavioral deficits in preweanling pups. Future studies will investigate the effects of disturbed maternal-infant interactions on adult offspring and will include physiological and behavioral responses to stress, responses to pharmacological probes, blood pressure and immune response, thereby providing data for those who design interventions.
