Effects of anterior roof deafferentation on lordosis behavior and estrogen receptors in various brain regions of female rats

Abstract

This study investigated whether the estrogen receptors (ER), located at different brain areas and anterior pituitary (AP), changed after anterior roof deafferentation (ARD), and on the effects of facilitating the lordosis reflex in female rats. Female rats were ovariectomized and implanted with estradiol capsules. ARD or sham operation was performed with a Halász knife. All animals were tested for lordosis both before and after surgery. One day after the last test they were sacrificed. Cytosol and nuclear ER in the AP, medial preoptic area (MPOA), basal medial hypothalamus (BMH), amygdala (AMYG), septum (SEP), hippocampus (HPC), and cortex (CTX) were measured using an in vitro exchange assay. Rats with ARD showed significantly higher mean levels of lordosis quotient than the control and the sham groups before ARD surgery. An increase of both cytosol and nuclear ER in the BMH area compared to the control was observed, whereas the ER, in the SEP was reduced. ER in other areas were not affected by ARD. Serum estradiol and progesterone levels were not altered by the operation. These data suggest that the dorsal inhibitory pathway from the extrahypothalamus to the preoptic area and hypothalamus may modulate the estrogen receptor and the display of lordosis in female rats. Change of ER level in the BMH area may influence the hormonal sensitivity of lordosis in female rats.