Neurochemical changes in the offspring of rats subjected to stressful conditions during gestation

Influence of prenatal maternal stress on the immunocompetence of the offspring

To evaluate the effects of prenatal maternal stress on the development of humoral immunocompetence in the offspring and on their hormonal and immunologic responses to postnatal stress, gravid Sprague-Dawley rats were exposed daily on gestational days 15-21 to prenatal environmental stress [(PES) 15 unsignaled, inescapable electric foot-shocks (0.05 mA for 0.5 s)] or prenatal psychological stress [(PPS) pregnant rats were placed in the nonelectrified section of the apparatus and allowed to see, hear, and smell a nonpregnant partner being environmentally stressed]. Pregnant controls (PC) were placed in the apparatus for 30 min. Serum corticosterone (CCS) and immunoglobulin G (IgG) levels were measured in the offspring every 7 days from birth to postnatal day (PND) 28. On PND 29-33, offspring were environmentally stressed; hormonal and immune status were determined on PND 34. Levels of IgG were reduced in PES and PPS offspring on PND 0 and in PES offspring on PND 7 and 28. These changes were unrelated to differences in CCS and did not reflect altered maternal-pup interactions or nutritional factors. Postnatal stress was immunosuppressive in PC pups but did not alter immune parameters in PPS offspring. In PES females, postnatal stress was also immunosuppressive. However, in PES males with already reduced IgG levels postnatal stress enhanced immune function. These data provide the first experimental evidence that prenatal maternal stress can alter immune parameters in the rat offspring.

Aversive prenatal stimulation: effects on behavioral, biochemical, and somatic ontogeny in the rat

Electric foot shock administered to pregnant rats altered the ontogeny of spontaneous motor activity in their pups. Prenatally stimulated (PMS) offspring were more active than controls on Days 1-10 but less active during the 3rd postpartum week. The age of peak activity, a major developmental landmark, occurred in PMS pups around 10 days of age; in controls maximum activity was not seen until the 3rd week. This effect was independent of the gender of the offspring and the timing of the gestational stimulation. Its appearance in both cross-fostered and fostered pups indicated the prenatal origin of the effect. The maturation of spontaneous alternation behavior and several reflexes and the appearance of physical features were not affected by prenatal stimulation. Moreover, both PMS and control groups exhibited an age-related increase in brain concentrations of norepinephrine, serotonin, and 5-hydroxyindoleacetic acid. These findings indicate that spontaneous motor activity is uniquely sensitive to PMS, and as far as can be determined here, PMS produces no generalized alteration in behavioral and physical ontogeny.