THE EFFECTS OF PRENATAL STRESS ON OFFSPRING OF RATS BRED FOR GOOD AND POOR AVOIDANCE BEHAVIOR (CORTICOSTERONE, EMOTIONALITY)
Abstract
The present study was undertaken to assess the effects of prenatal stress on a number of behavioral and physiological functions in the offspring when tested in adulthood. Pregnant rats of two genetic lines bred for good (HA) or poor (LA) shuttlebox avoidance behavior were subjected to a stress of heat, light, and restraint from Day 1 to 21 of gestation. This stress was shown to repeatedly produce a stress response in the pregnant dams, as measured by plasma concentrations of corticosterone. In Experiment 1, the following measures were obtained: (1) open-field ambulation, rearing and defecation, (2) number of avoidance responses made, and (3) basal and stress-induced levels of corticosterone. Prenatal stress decreased open-field ambulation in females but not males. The treatment also decreased open-field defecation but the effect was observed only in animals that were tested in the open field before avoidance training. Prenatal stress also decreased basal concentrations of corticosterone in females of the LA line, and decreased stress-induced concentrations of plasma corticosterone in females of both lines. These measures were not affected in males of either line. In Experiment 2, prenatally stressed and control males were compared on acquisition of a conditioned emotional response (CER). Prenatal stress did not affect emotional conditioning of male offspring. In Experiment 3, open-field and hormone measures were obtained on metestrus (D-1) and proestrus of the estrous cycle. Vaginal cytology was examined for all subjects. Prenatal stress did not affect estrogen-sensitive changes in vaginal cytology or uterine weight. The behavioral effects produced by prenatal stress do not appear to be mediated by changes in gonadal hormones.
Degree
Ph.D.
Subject Area
Psychobiology
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