| Abstract:
Since the stress influences the biological processes, in the present study the effect of prenatal immobilization stress and testostrone treatment of male rats were studied. Adult male and female wistar rats were copulated. Pregnant rats were divided into control and experimental groups. All groups were kept under the laboratory conditions (controlled temperature and photoperiod). The pregnant control rats were under no stress. Experimental groups were put in the special adjustable restrainer for 2 house every day for one week from the beginning of the. third week of pregnancy (14 th day) which is the development period of the nervous system, the sexual dimorphic nucleus and probably other nuclei of brain. The male off springs of control and stress group at the age of 80 days were divided in 5 groups. Four groups received respectively 50, 125, 200, and 300 mg Testosterone Enantate through IP injection for one week. The 5 th group received vehicle. At the age of 87 days fear behavior was measured by using elevated plus maze and different parameters were observed. Our results showed that injection of 125 ug testosterone decreased fear behavior comparing with controls which is probably through the inhibitory effects of testosterone on hypothalamus - hypophysis - axis (HPA). Prenatal stressed comparing with control were more fearful. This effect is because of the changes in some brain nuclei and increase of corticotropin releasing hormone (CRF). In conclusion it seems that prenatal immobilization affects fear behavior and testosterone treatment dose dependently decrease this behavior.
|