Reduced proceptivity and sex-motivated behaviors in the female rat after repeated copulation in paced and non-paced mating: effect of changing the male

Abstract

The mating inhibition after repeated copulation (sexual satiety) and its re-commencement after changing the sexually active partner (Coolidge effect) are well recognized phenomena in males, but their occurrence in females is little explored. These two phenomena were compared in conditions when the female regulates copulation timing (pacing) and under non-paced mating. Female rats selected in proestrus copulated incessantly for 3 h with two different partners (for 90 min each), both of them sexually active and unknown for the female. During the entire test we recorded the hop/dart and ear wiggling frequencies and the lordosis quotient. In the pacing test we also registered the percentage of exits and the return latencies after mounts, intromissions and ejaculation within each copulatory series, the mean time the female spent in the neutral chamber and the number of crossings. In the non-paced mating situation there was a reduction in ear wiggling and hop/darting frequencies after 3 h of constant copulation. In the paced mating condition, also by the end of the test, the female spent more time in the neutral compartment and showed fewer crossings to the male's zone. Only when the female regulated mating, the change of the male provoked an increased hop/darting frequency accompanied by a reduced percentage of exits from the male's chamber after an intromission and in the time in the neutral compartment. These changes were not associated with alterations in receptivity, which was maximal along the test. Data are discussed by comparing the mating conditions and the sex differences in the effect of repeated copulation and partner replacement.

Keywords: Paced and non-paced mating; Proceptivity; Rat; Receptivity; Sexual satiety.