Female presence during postejaculatory interval facilitates penile erection and 22-kHz vocalization in male rats.

Abstract

During the postejaculatory interval (PEI), male rats exhibit prolonged immobility, 22-kHz vocalization, and penile erections. To test whether females modulate these behaviors, females were removed after the first or second ejaculation or left in the test chamber. Female presence during the PEI delayed exploratory behavior and facilitated vocalization and erection. Female stimulation of vocalization is consistent with the hypothesis that vocalization has a communicative function, not just a thermoregulatory one. The timing of the effect of females on erection suggests that males are sexually arousable well before they resume copulation. Therefore, erection may be better than vocalization as an indicator of the male's sexual refractoriness. The findings also challenge the conventional view that the PEI comprises absolute and relative sexual refractory periods marked, respectively, by the presence and absence of 22-kHz vocalization.

Neural Substrates for Sexual Preference and Motivation in the Female and Male Rat

“…Sexual quiescence follows each ejaculation in many mammalian species including man, albeit the length of the quiescence, the postejaculatory refractory period, 42 varies considerably between species and even among substrains of a particular species. In his pioneering works on male sexual behavior in mice with different genetic backgrounds, McGill 43,44 described that the mating pattern of the C57BL/6 male is characterized by its speed in achieving ejaculation combined with a long period required to recover sexual drive after an ejaculation.…”

“…In his pioneering works on male sexual behavior in mice with different genetic backgrounds, McGill 43,44 described that the mating pattern of the C57BL/6 male is characterized by its speed in achieving ejaculation combined with a long period required to recover sexual drive after an ejaculation. The postejaculatory quiescence appears to be a result of decreased sexual drive and not due to sexual exhaustion, which usually lasts for several days following multiple ejaculations, 45 because ejaculated male rats exhibit penile erections 42 and BALB/c males may attempt to mate when presented with a new female. 43 Thus, C57BL/6 is a typical single ejaculator, whereas the rat or ICR mouse, which accomplishes ejaculation in succession, with 5-to 10-min intervals, is a multiple ejaculator.…”

Antiaging effect of Cordyceps sinensis extract

“…Two weeks after the ovariectomy, they were brought into estrus with injections of estradiol benzoate (20 μg/ rat s.c.) and progesterone (500 μg/rat s.c.), 48 h and 4 h, respectively, before tests. The following behavioral measures of copulation were used: mount latency, time from introduction of the stimulus female to the first attempt to mount the female, and ejaculation latency (Sachs and Bialy, 2000). This experiment was conducted during the dark phase in a room with low levels of red light.…”

Sexual performance and precontact 50-kHz ultrasonic vocalizations in WAG/Rij rats: Effects of opioid receptor treatment

“…Recently, more data have supported the hypothesis that ultrasonic vocalizations in rats serve a communication function [11][12][13][14][15]. Parallel to the communicational role, ultrasonic vocalizations at the 50-kHz band in rats can be an indicator of a positive emotional state which relates to the dopamine level, mu opioid receptor stimulation in the ventral tegmental area, and self-and drug-stimulation of the rewarding systems [16][17][18][19][20][21].…”

“…After ejaculation, male rats display postejaculatory 22-kHz vocalizations [24] simultaneously with sleep-like EEG [25]. The function of the postejaculatory vocalizations is still poorly understood [26] although such vocalizations depend on female presence in the copulatory chamber [11]. In an aversive situation, 22-kHz vocalizations serve as alarm cries and change the behavior in a colony of rats [27,28], depend on acetylcholine stimulation [16], and reflect anxiety but not fear [29].…”