Regulation of estrogen and phytoestrogen on the dopaminergic systems of amygdala in rats / 生理学报

ABSTRACT

In vivo fast cyclic voltammetry (FCV) was used to investigate dopamine (DA) release from amygdala (Amy) of female rats in different phases of estrus cycle, ovaricectomized (OVX) rats and male rats. Tyrosine hydroxylase (TH) immunohistochemistry was employed to measure the numbers of immunoreactive neurons in ventral tegmental area (VTA) of midbrain in the rats. We also observed the effect of intracerebroventricular injection of phytoestrogen-soy isoflavones on DA release from the Amy. The results are as follows DA release from the Amy of proestrus female rats was apparently higher than that in estrus, metaestrus, diestrus female rats and OVX rats. Amy DA release and the numbers of the TH immunoreactive neurons in VTA showed a significant sex difference. DA release from Amy of female and OVX rats increased significantly within 5 min after i.c.v injection of soy isoflavones, which elicited no effects in male rats. The above-mentioned results suggest that endogenous estrogen may play an important role in regulating the activity of DA neurons in mid-limbic systems, and that soy isoflavones exert an estrogen-like effect on the dopaminergic systems in the Amy.