Effect of oestradiol on the responses of regional brain serotonin to stress in the ovariectomized rat

Abstract

The effect of oestradiol on the response of regional brain 5-hydroxytryptamine (serotonin, 5-HT) to 24 hours electrical footshock was investigated in ovariectomized rats. The stress applied four weeks after ovariectomy induced significant decreases in 5-HT concentrations in the fronto-parietal brain cortex (Bc), hippocampus (Hipp), striatum (CP), medial-basal hypothalamus (MBH) and the preoptic-anterior hypothalamic area (PAHA). Pretreatment with oestradiol prevented the footshock-induced decreases in 5-HT in the Hipp, CP, MBH and the PAHA. It was concluded that oestradiol may prevent stress-induced response of regional brain 5-HT in ovariectomized rats. An interaction between oestradiol and brain 5-HT is proposed in the control of the course of the oestrous cycles in stressful situations.