Inhibitory Pathway for Female Sexual Behavior in Male Rat Brain: Effect of Medial Forebrain Bundle (MFB) Cuts

Abstract

In order to clarify the role of the medial forebrain bundle (MFB) in regulating female sexual behavior in male rats, lordosis and soliciting behavior were observed after transection of it. Male rats were castrated and received cutting of the bilateral MFB at the suprachiasmatic level or sham operation. As control groups, male and female rats were castrated without brain surgery. Behavioral test was carried out after implantation of Silastic tubes containing estradiol. As a result, all males with MFB cuts showed lordosis behavior. Lordosis quotient in this group was comparable to that of female control and was higher than those in the control male and sham male rats. Half male rats with MFB cuts but none of control and of sham males showed soliciting behavior. These results suggest that the MFB is an important inhibitory pathway for female sexual behavior in male rats.