Physiology &Behavior, Vol. 42, pp. 323-329. Copyright ©Pergamon Press pie, 1988. Printed in the U.S.A. 0031-9384/88 $3.00 + .00 Stressor Controllability During Pregnancy Influences Pituitary-Adrenal Hormone Concentrations and Analgesic Responsiveness in Offspring LOREY K. TAKAHASHI, 1 NED H. KALIN, CHARLES M. BARKSDALE, JENNIFER A. VANDEN BURGT Department of Psychiatry, University of Wisconsin Medical School, Madison, WI 53792 Psychiatry Service, W. S. Middleton Memorial Veterans Hospital, Madison, WI 53705 AND MARK S. BROWNFIELD Department of Comparative Biosciences, School of Veterinary Medicine University of Wisconsin, Madison, WI 53706 Received 23 September 1987 TAKAHASHI, L. K., N. H. KALIN, C. M. BARKSDALE, J. A. VANDEN BURGT AND M. S. BROWNFIELD. Stressor controllability duringpregnancy influences pituitary-adrenal hormone concentrations and analgesic responsive- ness in offspring. PHYSIOL BEHAV 42(4) 323-329, 1988.--Repeated escapable shock, yoked-inescapable shock, or no-shock treatments were administered to female rats before parturition to investigate the effects of stressor controllability on offspring pituitary-adrenal hormone concentrations and stress-induced analgesic reactions. Female rats exposed to escapable shock treatments received tail-shock in boxes containing a wheel that allowed shocks to be terminated after rotation. Rats in the yoked-inescapable shock group received an identical amount and pattern of tail-shock. However, shock was terminated only after wheel rotation by the rat undergoing escapable shock treatments. Female rats in the no-shock group were simply placed in wheel-turn boxes. Fourteen-day-old offspring were exposed for 10-rain to either a separation-stress or shock-induced stress test. The former test consisted of separating and isolating the pup from the mother and siblings, whereas the latter involved the administration of five brief, 1.0 see, low intensity, 0.5 mA, foot-shocks. Immediately after exposure to foot-shocks, pups were given a tail-flick test to assess their analgesic response. Plasma was obtained from pups immediately after separation and tail-flick tests and ACTH and corticosterone concentrations were assayed by radioimmunoassay. Results indicated that prenatal inescapable shock treatments resulted in offspring with significantly higher plasma ACTH and corticosterone concentrations than offspring exposed to prenatal escapable shock or no-shock treatments. Offspring of females exposed to inescapable shock also exhibited greater increases from basal concentrations in ACTH and corticosterone after stress. Furthermore, prenatal escapable and inescapable shock treat- ments significantly altered shock-induced analgesic thresholds. That is, only offspring from rats treated with no-shock exhibited a stress-induced analgesic response after exposure to foot-shock. Taken together, these data indicate that during pregnancy the degree of behavioral control exerted over shock significantly alters offspring pituitary-adrenal release of stress-related hormones. In addition, prenatal exposure to shock treatments, whether escapable or inescapable, influences the development of systems associated with stress-induced analgesia. Prenatal stress Escapable shock Inescapable shock Rat pups Stressor controllability ACTH Corticosterone Analgesia THE effects of prenatal stress on the development of brain and behavior have been the subject of intense investigations. These studies have employed various animal models and stress paradigms. For example, Ward and colleagues [44,45] as well as other researchers [3, 12, 28] have shown that rats exposed to stress during the last trimester of pregnancy produce offspring with significant alterations in sexual be- havior and in the hypothalamic-pituitary-gonadal system. As ~Requests for reprints should be addressed to Dr. Lorey K. Takahashi, Psychiatry Service, VA Hospital, 2500 Overlook Terrace, Madison, WI 53705. 323