Ovariectomized rats, with bilateral cannulae near the VMN, were hormonally primed with 10 μg EB and 500 μg P. Four to six h after the P injection, rats were tested for sexual receptivity (PRE). After the pretest for sexual behavior, females were infused with 200 ng 8-OH-DPAT or were coinfused with 200 ng 8-OH-DPAT and 2000 ng DOI. The numbers of subjects for 8-OH-DPAT and 8-OH-DPAT plus DOI rats were 13 and 10, respectively. Data are the mean ± S.E. L/M ratios before infusion (PRE) and for six consecutive 5 min intervals after infusion. * indicates a significant difference from the pretest within each 5 min test interval. # indicates a significant difference between rats infused with 8-OH-DPAT and rats coinfused with 8-OH-DPAT and DOI within each 5 min time interval.