Tonic pain response during inflammation and stress-induced corticosterone variations in prenatally stressed infant rats: effects of maternal buspirone injected during pregnancy.

We studied the effects of injections of 5-HT1A-agonist buspirone to pregnant rats before stress exposure on corticosterone level in the dynamics of stress response to inflammatory-induced pain in 7-day-old offspring. During the period of the hypothalamic-pituitary-adrenal system hyporeactivity, the pain response in the formalin test was associated with stress-related corticosterone variations. Maternal buspirone normalized the pain reaction in prenatally stressed rats during all periods of the formalin test and modified the dynamics of the corticosterone response. In 1 day after the formalin test, the basal level of this hormone in blood plasma remained increased. Maternal buspirone increased the resistance of the nociceptive and stress-systems to inflammatory-induced pain response in prenatally stressed rats.