Abstract

Background: There are different kinds of stress on mothers during prenatal period. The present study investigated the effects of exposure to chronic heterogeneous sequential stress during prenatal period on formalin-induced nociceptive behavior in adult offspring. Methods: In the present study, animals were divided in stressed and non-stressed groups and their offspring divided in male and female groups. Heterogeneous sequential stress including food deprivation, water deprivation, restraint, restraint at room temperature, restraint at 4°C, forced swimming and social isolation were applied during days 9 to 19 of gestation. Formalin test as chemical model and hot-plate as thermal pain model were used in rats. Findings: Chronic heterogeneous sequential stress increased the nociceptive behaviors in male rats in first part and in female rats in second part of phase 2 of formalin test compared with controls. Conclusion: The result of this study showed that chronic heterogeneous sequential stress in rats increased the nociceptive behaviours in second phase of formalin test in a gender-dependent order; which suggested chronic heterogeneous sequential stress may be useful in evaluating the basic mechanism of exposure to chronic heterogeneous sequential stress during prenatal period on in adult offspring.