The role of ovarian sympathetic innervation in the control of estrous responsiveness in the rat

This study examined the contribution of the superior ovarian nerve (SON) to estrous responsiveness and ovarian function in cycling rats. Section of the SON was carried out at 1100 on proestrus, and lordotic responsiveness was measured at 1500, 1700, and 2100 on that day and at 0900, 1200, and 1500 on the day of estrus. SON section decreased lordosis intensity significantly at 1500 and 1700 on proestrus and at 0900 on estrus. Pacing of sexual contacts with males was decreased at 2100 in nerve-sectioned (Nervx) animals when compared with sham-operated controls (SHAM). Serum progesterone (P) concentrations were significantly lower in Nervx animals than in Sham animals 30 min after surgery, but were not different between groups at 4.5 hr. Serum estradiol (E2) concentrations did not differ between groups at either time. In addition, Nervx and Sham groups did not differ on measures of pregnancy/pseudopregnancy initiation or on measures of ovarian function 10 days after surgery. These data suggest that the integrity of the SON is necessary for the display of full estrous responsiveness in cycling rats, and suggest that the acute decreases in serum P occurring as a consequence of SON section may be responsible for the deficits seen in Nervx animals.