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PubMed1992

Hippocampal electrical activity in the female rat: the estrous cycle, copulation, parturition, and pup retrieval.

Hippocampal electrical activity was examined in female rats across the four phases of the estrous cycle, as well as during copulation, parturition, and pup retrieval. Possible hormonal effects on hippocampal activity were examined by recording daily during struggling and immobility throughout five estrous cycles. No differences in the characteristics of rhythmical slow activity (RSA), large-amplitude irregular activity (LIA), or their relation to behavior were found between the phases of the estrous cycle. Behaviors examined during copulation were lordosis, hopping, and ear wiggling. Lordosis and ear wiggling were both accompanied by irregular waves, with some low frequency RSA also present during lordosis. Hopping was accompanied by RSA which was greater in amplitude and frequency than RSA during walking. Parturition behaviors examined included body extensions, genital or pup licking, and 'body flattening'. Body extensions were found to be associated with irregular hippocampal activity, and appeared to be a Type 2 behavior. Interestingly, sudden suppressions of the hippocampal record lasting 1-5 s often preceded body extensions. Irregular hippocampal activity was present at all times during genital and pup licking. Body flattening was typically accompanied by very high amplitude irregular waves which, although the rats were awake, resembled a sleeping hippocampal pattern. Pup retrieval involved walking and was thus always accompanied by RSA.

Animals↗
PubMed1989

Copulation-illness associations in male rats: lithium chloride dose and delay manipulations.

Male rats that receive an injection of lithium chloride (LiCl) after each pairing with an estrous female gradually decrease their copulatory behaviors. In the present experiments we demonstrated that a 6.0 mEq/kg (0.3 M, 20 ml/kg) dose of LiCl injected after trials spaced twice weekly at 3-4-day intervals induced more rapid acquisition of copulation-illness associations than a 3.0 mEq/kg (0.15 M, 20 ml/kg) dose. Contingent 0.3 M saline or noncontingent 0.3 M LiCl injections did not affect copulatory behaviors. The location of the male rat (home cage or test chamber) during a portion of the aversive state induced by LiCl did not influence rate of acquisition. Copulation-illness associations, once established, were retained over a 60-day interval. Comparable decrements in copulatory behaviors were evident when LiCl was injected at 1-, 5-, or 15-min intervals after pairings with estrous females when the males were detained in the test chambers during the delay intervals; decrements were not observed when the interval was increased to 30 or 60 min. An electric shock analog to the aversive state induced by LiCl did not induce decrements in copulatory behaviors. It was suggested that odor-illness associations may, in part, account for the decrements in copulatory behaviors in this paradigm.

Animals↗
PubMed1983

Can male decorticate rats copulate?

Sexually experienced or naive male rats, subjected to neocortex removal or neocortex plus hippocampus removal, were paired with female rats for up to 180 days and compared with control rats with respect to success and latency to impregnate the female. All of the control rats and half of the brain-damaged rats successfully impregnated female rats at least once. Success was not correlated with lesion type or presurgical experience. The brain-damaged rats took longer to impregnate the females than control rats. Since the ablations were extensive, more than 95% of the neocortex in many rats, the study shows that decorticate rats can copulate. Presumably the intact subcortical structures are sufficient for male copulation, but cortical structures in some way facilitate rapid female impregnation.

Animals↗
PubMed1975

Suppression of precocial copulation by progesterone implants in the male chick forebrain.

Precocial copulation in 2-wk.-old male chicks, described behaviorally as free mount, tread, posterior contact, waggle, peek, and seize, was developed through hand-training experience and androgen treatment. Crystalline progesterone was then implanted in various forebrain or midbrain regions. Results indicated that progesterone inhibited copulatory behavior when placed in the periventricular areas of the preoptic-hypothalamic continuum. Progesterone implants in the preoptic lateral forebrain bundle regions also suppressed precocial copulation. Forebrain implants of cholesterol did not result in copulatory inhibition. The suppression of copulatory behavior was not accompanied by loss of weight or deficits in general activity or comb growth. These data indicate that brain regions responsible for progesterone-induced copulatory inhibition are similar in neuroanatomical distribution to those involved in testosterone-induced copulatory activation.

Age Factors↗
PubMed1975

The septum: neural systems involved in eating, drinking, irritability, nuricide, copulation, and activity in rats.

Eating, drinking, irritability, muricide, and copulation were measured in 45 male rats before and after one of three coronal knife cuts in the septal region or a control operation; in addition, activity was measured postoperatively. (a) Cuts posteroventral to the septum resulted in slight hypophagia, marked hyperdipsia, irritability, asexuality, and decrease in activity. (b) Cuts of the fornix resulted only in slight decrease in activity. (c) Cuts through the anterior septum resulted in irritability, slight hyposexuality, and slight decrease in activity. No significant correlations between the various behavioral effects were found. It was suggested that the neural pathways mediating eating, drinking, irritability, muricide, copulation, and activity are relatively distinct and that neural activity in the septal region probably does not influence behavior in any unitary fashion.

Aggression↗
PubMed1999

Morphine injected into the paraventricular nucleus of the hypothalamus prevents noncontact penile erections and impairs copulation: involvement of nitric oxide.

Male rats show four to six penile erection episodes when put in the presence of an inaccessible receptive female for 80 min. These noncontact erections occur concomitantly with an increase in nitric oxide production in the paraventricular nucleus of the hypothalamus. This is shown by the increases in the NO2- and NO3- concentrations in the paraventricular dialysate obtained from these males by in vivo microdialysis. The NO2- concentration increased from 0.75 +/- 0. 10 microm to 2.89 +/- 0.39 microm and that of NO3- from 4.13 +/- 0. 58 microm to 9.5 +/- 1.2 microm. Morphine (0.5, 1 and 5 microg), given unilaterally into the paraventricular nucleus 15 min before the introduction of the receptive female, prevented the NO2- and NO3- increases, and noncontact erections, dose-dependently. In contrast, the kappa opioid receptor agonist U-69 593 (5 microg) was ineffective. The effects of morphine on NO2- and NO3-, and on noncontact erections, were prevented by the opiate receptor antagonist naloxone (10 microg) injected into the paraventricular nucleus 15 min before morphine. The NO2- and NO3- concentrations were also increased in the paraventricular dialysate of male rats during copulation, i.e. when in copula penile erections occurred. As found with noncontact erections, morphine, but not U-69 593, injected into the paraventricular nucleus prevented the NO2- and NO3- increases and impaired copulatory behaviour, and naloxone prevented these responses when given before morphine. Although some diffusion of the opiate to surrounding brain areas cannot be completely ruled out, the present results suggest that morphine acts through mu receptors in the paraventricular nucleus to impair noncontact erections and copulation. These effects of morphine are apparently mediated by a prevention of the increased nitric oxide production that occurs in the paraventricular nucleus of the hypothalamus of male rats during sexual activity.

Animals↗
PubMed1984

Dissociation of copulation from ovulation in pregnant rabbits.

Experiments were designed to determine why copulation in the pregnant rabbit does not terminate pregnancy while treatment with ovulatory doses of luteinizing hormone (LH) human chorionic gonadotropin (hCG) or luteinizing hormone-releasing hormone (LHRH) is known to do so. Pregnant rabbits (Day 8) were mated or were injected with hCG (25 IU/doe) or LHRH (1, 10 micrograms/kg). Serial blood samples were collected over the next 72 h and analyzed for content of LH, follicle-stimulating hormone (FSH) and progesterone. At sacrifice, uteri and ovaries from these animals were examined for viability of the embryos and for signs of recent ovulation. Injection of hCG or LHRH into pregnant animals led to ovulation and to patterns of LH, FSH and progesterone secretion like those which precede ovulation in estrous rabbits. However, mating the pregnant does did not lead to ovulation or to any changes in the circulating hormones. To investigate whether the elevated levels of progesterone during pregnancy were responsible for the dissociation of coitus from ovulation, nonpregnant rabbits were injected with progesterone (2 mg/kg) and then mated or injected with hCG or LHRH. In virtually every respect, the numbers of ovulations and the patterns of hormone secretion in the progesterone-treated, nonpregnant rabbits mimicked those observed in the 8-day pregnant animals; injection of hCG or LHRH caused ovulation and hormonal surges while hCG caused ovulation only. Mating did not lead to ovulation or any change in blood levels of LH, FSH or progesterone. Taken together, the results show that the elevated circulating levels of progesterone, characteristic of pregnancy, are probably responsible for the dissociation of copulation from gonadotropin release in pregnant rabbits.

Animals↗
PubMed1975

Pregnancy in cactus mice: effects of prolonged copulation.

The postejaculatory copulations of cactus mice are demonstrated to function in facilitating neuroendocrine responses necessary for pregnancy. Whereas estrous cycles were altered after just 10 percent of the tests terminated after one ejaculatory series, females became either pregnant or pseudopregnant after 80 percent of tests continued at least to sexual satiety (30 minutes with no copulations).

Animals↗
PubMed1966

"Copulation-reward site" in the posterior hypothalamus.

Posterior hypothalamic selfstimulation of male rats, in which monopolar,platinum electrodes had been belaterally implanted, increased after systdmic injection of testosterone. constant stimulation to the same site elicited immediate copulation with estrous female rats. During constant stimulation males would press a bar to open a door for access to females. Even after ejaculation, males continued to open the door and to display sexual activity until stimulation terminated. Posterior hypothalamic stimulation is like normal sexual stimulation; it is rewarding, the reward varies with the amount of the sex hormone, and it elicits motivated copulation.

Animals↗
PubMed1999

Sexual behavior and extragroup copulations in a wild population of common marmosets (Callithrix jacchus).

Sexual behavior and mating patterns are described for 3 free-ranging groups of common marmosets living in a coastal forest in northeastern Brazil. Each group contained 2 breeding females. Within groups, sexual behavior was generally restricted to breeding females and a single behaviorally dominant male. Of 101 mounts and copulations, 24 involved pairings of individuals from 2 different groups. Extragroup sexual behavior was performed by both breeding and nonbreeding group members, and 65% of all adults mounted or copulated with an extragroup individual at least once. Sexual behavior occurred throughout the female reproductive cycle but was significantly more frequent during an 11-day 'conception period'. Thus, while female marmosets show no physical signs of estrus, both males and females likely do have some information about the timing of ovulation. Mating patterns in this population included both polygyny and monogamy and varied between groups and over time.

Animals↗
PubMed1977

Effects of repeated morphine administration on copulation and on the hypothalamic-pituitary-gonadal axis of male rats.

Adult male rats were administered morphine twice a day for 45 days and the effects of morphine on the copulation rate, the weight of various organs, and on the hypothalamic-pituitary-gonadal axis were examined. Morphine administered rats showed a loss of weight, hypertrophy of the adrenals, decreased weight of accessory sex organs, low sperm count, and decreased copulation rate. The contents of the luteinizing hormone releasing hormone in the hypothalamus and the luteinizing hormone in the pituitary remained unchanged. Serum luteinizing hormone and testosterone levels decreased, but serum follicle-stimulating hormone levels increased. These results suggest that morphine inhibits the hypothalamic-pituitary-gonadal axis and causes a diminution in the number of fertilizations of the partner females.

Animals↗
PubMed1992

Effect of (-)-para-fluoro-deprenyl on survival and copulation in male rats.

Six-month old male rats were treated with 0.25 mg/kg, s.c., (-)p-fluoro-deprenyl (n = 40) or salt solution (n = 20) three times a week for 25 months. Three of the 20 saline-treated and 15 of the 40 drug-treated males survived (p = 0.05). Sexual activity of the survivors was tested at the end of the experiment. Three of the (-)p-fluoro-deprenyl-treated 31-month-old males proved to be sexually fully active, though, Wistar rats lose their ability to ejaculate by completing their second year of life. Non-copulator, 13 month old male rats were treated instead of the usually used 0.25 mg/kg dose with 0.01 mg/kg, s.c., (-)deprenyl (n = 9), (-)p-fluoro-deprenyl (n = 9) and salt solution (n = 9), three times a week, for 82 weeks and mating activity was tested weekly. The lifespan of the non-copulators was very short: 102 weeks for saline (n = 9), 106 weeks for (-)deprenyl (n = 8) and 104 weeks for (-)p-fluoro-deprenyl (n = 7). Survival was lightly changed by this very small dose treatment, one (-)deprenyl-treated male and two (-)p-fluoro-deprenyl-treated rats remained alive. The copulatory activity, however, was substantially improved.

Animals↗
PubMed1979

[Supression by copulation of the inhibitory effect of p-chlorophenylalanine on rat ovulation (author's transl)].

The effect of copulating on reflex ovulation was studied in rat. The effect of PCPA (300 mg/kg, i.p.) on ovulation and reproduction was compared by evaluating number of oocytes in tubes, histologic features of ovaries, vaginal cycle, insemination, fertilization and number of embryos per rat. PCPA, administered on 9th and 16th h of the estrus phase, totally inhibits ovulation, stimulates reproductive behaviour and prolongs the estrogenic phase. When the animals are kept in copulatory conditions for 16 or 46 hours, the inhibition induced in ovulation disappears to the extent that 60% of the rats become pregnant though the number of embryos is under that of the control group. The farther the treatment with PCPA within the same cycle in the ovulatory period, the greater the inhibitory effect on ovulation is and the lesser the neutralizing effect produced by reflexes related to copulation. Administration of PCPA at the 16 hour of the diestrus causes a greater increase in the average number of embryos-as compared to administration at the 9 hour. In periods longer than 48 hours before ovulation, the inhibition brought about by PCPA is not suppressed by copulatory conditions kept for 16 or 24 hours and is only neutralized if they are kept during a complete cycle. Those treated with PCPA in the diestrus phase and maintained in copulatory conditions for 46 hours, present a higher average of embryos than those maintained in similar conditions for 16 hours.

Animals↗
PubMed1997

Copulation and sexual congress of Leptorhynchoides thecatus (Acanthocephala).

Pairs of the acanthocephalan Leptorhynchoides thecatus from laboratory infections were observed copulating at 21 days, 5 wk, and 12 wk postinfection (PI) in green sunfish, Lepomis cyanellus. Additionally, copulating pairs of worms from natural infections were observed. In each instance of paired males and females, the male was in 1 pyloric cecum of the fish and the female in another. Each had its posterior end protruding into the intestinal lumen at the point from which the ceca arise. The completely extruded bursa of the male fully enclosed the posterior end of the female in a firm attachment. In 1 instance at 5 wk PI, 2 males were observed in copula. One male had its copulatory bursa completely retracted, and the copulatory bursa of the other male was positioned just as though the mate were a female. Based on these and previous findings, it is concluded that male acanthocephalans mate indiscriminately and often throughout their lives. Habitation of ceca maximizes sexual congress because individuals often are positioned with their posterior ends extending into the intestinal lumen within the small area from which ceca originate. Emigration to find a mate is unnecessary.

Acanthocephala↗
PubMed1982

[Experiments in vitro with Litomosoides carinii (Nematoda: Filarioidea) II. Influence of different sera on the release of microfilariae and experiments on the readiness for copulation of the worms (author's transl)].

When fetal calf serum or human serum is added to the culture medium Tc 199, adult females of Litomosoides carinii release the same amount of microfilariae in vitro as after addition of cotton rat serum. In contrast, in media with serum of Meriones unguiculatus or Mastomys natalensis only a few microfilariae are released; moreover, addition of Mastomys serum immobilizes them. When males and females are kept together, the same amount of microfilariae is released as compared with single females. Worms 4 weeks of age (i.e., about 2 weeks before copulation) maintained in medium Tc 199 with 33% cotton rat serum do not mate (no insemination of the females). However, the females live 18 days (harmonic mean) in vitro and grow on average 5 mm in length (28%) and the males roll up their tails in characteristic manner. Worms 5 or 6 weeks of age kept in pairs for 45 to 6 days in vitro were implanted into cotton rats. In vivo they grew to normal length, copulated and delivered microfilariae into the circulating blood. Females implanted solely into the recipient grew as well but remained sterile; this means that no insemination took place in vitro.

Animals↗
PubMedDate not supplied

[The role of testosterone undecanoate in correcting disorders of the copulative function].

Testosterone andecanoate (andriol) was used for treatment of copulative dysfunction in 18 young and middle-aged males in a dose 160 mg/day (a 10-12-day treatment course) or 40-80 mg/day (up to 6 week maintenance course). Clinical responses concerning such sexual symptoms as libido, erection, ejaculation and orgasm were achieved in most of the patients. Pretreatment blood levels of testosterone were not decreased. The treatment aroused these levels which persisted higher that pretreatment ones for 3 months. Estradiol was slightly higher after the treatment. Andriol is recommended for treatment of copulative dysfunction in young and middle-aged males.

Adult↗
PubMed1993

Estrus termination following copulation in female guinea pigs.

In the female guinea pig, estrus is inhibited after copulation. This study explored the role of the endocrine status of the male on the termination of the lordosis response in females. Ovariectomized females were treated with estradiol benzoate and progesterone to induce estrus and were then mated with males when the males were intact, castrated, and castrated and treated with testosterone propionate (TP). Lordosis responses were recorded prior to and following mating. Females who received an ejaculation from a castrated male remained sexually receptive longer than the females mated with intact males, or those males that were castrated and treated with TP. These results support the hypothesis that the factor(s) responsible for termination of estrus in females are found in the ejaculate of the male and are testosterone dependent.

Animals↗
PubMed1989

The effects of intrathecal administration of the dopamine agonist apomorphine on penile reflexes and copulation in the male rat.

Relatively high doses of systemically administered apomorphine inhibit penile reflexes. It is possible that these inhibitory effects are due, at least in part, to actions of apomorphine on the lumbosacral spinal cord. The present experiments examined this possibility by injecting apomorphine (10 and 50 micrograms/5.0 microliters vehicle) into the lumbosacral subarachnoid space through chronic, indwelling cannulae. Such injections impaired ex copula penile reflexes, slowed the rate of copulation, and decreased the number of intromissions preceding ejaculation. These results suggest that lumbosacral cord dopamine receptors may normally regulate male sexual performance.

Animals↗