Assessment of functional alterations in rats exposed prenatally to five central nervous system depressants (2). Thermic response of the Fi offspring to chlorpromazine in adulthood

Abstract Effects of prenatal exposure to 5 CNS-depressants on the functional development of rat brain was assessed by examination of thermic response to chlorpromazine (CPZ). Pregnant Wistar-Imamichi rats were injected s.c. with phenobarbital (Phe, 10 mg/kg), haloperidol (Hal, 0.1), imipramine (Im, 5), nitrazepam (Nt, 2), 5% ethanol (EtOH, 1 ml/kg) and saline (1 ml/ kg) from day 1 to day 21 of gestation (group A) or from day 15 to day 21 of gestation (group B). The Fi rats were allowed to mature and tested for the thermic response to CPZ at 8 and 13 weeks of age. CPZ in a dose of 5 ng/kg was injected i.p. between 10:00 and 10:30 a.m., and rectal temperature was determined for 6 hr. An increase in the baseline temperature -.cas shown in 8-week-old Phe-F1 rats and a decrease in Im-Fi and Hal-Fi rats. CPZ administration induced a marked decrease in rectal temperature in saline-Fi male and female rats until 3 hr after the injection. In contrast, rectal temperature in Im-F1 and EtOH-Fi male rats increased significantly with 2 peak values at 30 min and 3 hr after the injection of CPZ, and Hal-Fi males showed hyperthermia at 3 hr. In females, the rectal temperature decreased to about the same extent following CPZ administration in all groups except Hal-F1 females that showed hyperthermia at 3 hr. Hyperthermia by CPZ was also induced in 13-week-old Im-F1 and Hal-F1 male rats. The present results indicate that prenatal exposure to Im, Phe, Hal and EtOH develops alterations in thermoregulation in adulthood.