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At least 145 records · Page 8Linked to original sources
PubMed2003

An NMDA antagonist impairs copulation and the experience-induced enhancement of male sexual behavior in the rat.

Sexual experience facilitates subsequent male sexual behavior; activation of the N-methyl-D-aspartate (NMDA) glutamate receptor may play a role in this experience-induced enhancement. In this article, the authors report that systemic injections of MK-801, an NMDA receptor antagonist, impaired male sexual behavior in sexually naive and sexually experienced male rats. Furthermore, saline-treated rats that received 7 daily exposures to an inaccessible estrous female instead of sexual experience displayed enhancement of copulation on the following day. Injections of MK-801 before each of these exposures inhibited the experience-induced enhancement on the drug-free test on Day 8. These data suggest that stimulation of NMDA receptors enhances sexual performance immediately and mediates the experience-induced enhancement of subsequent copulatory behavior.

Animals↗
PubMed2001

Aphrodisiac evaluation in non-copulator male rats after chronic administration of Eurycoma longifolia Jack.

The aphrodisiac effect of Eurycoma longifolia Jack (0.5 g/kg) was evaluated in noncopulator male rats using an electrical cage. Fractions of E. longifolia Jack decreased the hesitation time of noncopulator male rats, throughout the investigation period. Furthermore, it possessed a transient increase in the percentage of the male rats responding to the right choice, more than 50% of the male rats scored "right choice" after 3 weeks post-treatment and the effect became more prominent after 8 weeks post-treatment (only 40-50% of the control male rats responded to the right choice) using the electrical copulation cage. Hence, this study lends further support to the use of the plant by indigenous populations as a traditional medicine for its aphrodisiac property.

Animals↗
PubMed1995

Mutually exclusive neuronal expression of peptides encoded by the FMRFa gene underlies a differential control of copulation in Lymnaea.

An innovative method, direct peptide profiling of small samples of nervous tissue by matrix-assisted laser desorption ionization mass spectrometry, in combination with peptide characterization, immunocytochemistry in conjunction with specific neuronal labeling by backfilling of the penis nerve, and bioassay of peptides was used to study the intrinsic neuronal expression patterns of distinct sets of related FMRFa peptides and their significance for the organization of male copulation behavior in the mollusk, Lymnaea stagnalis. Previous studies indicate that the sets of FMRFa-related and GDPFLRFa-related peptides are encoded by two alternatively spliced transcripts of the single FMRFa gene. Direct mass spectrometry revealed that both FMRFa-related and GDPFLRFa-related peptides are present in the penis nerve, the sole nerve that innervates the penis complex. Accordingly, authentic FMRFa, GDPFLRFa, and related peptides were purified from the penis complex. The loci of synthesis of FMRFa and related peptides could be traced to the right cerebral ventral lobe, those of GDPFLRFa and related peptides to the B group neurons in the right parietal ganglion and to a few unidentified neurons in the right pleural ganglion. Notwithstanding their related structures, the two sets of peptides have distinctly different actions on the penis retractor muscle.

Alternative Splicing↗
PubMed1981

The effect of LH and copulation on the number of spermatozoa in the rat testis.

In the present work we have re-examined our previous observations concerning the hormonal control of spermiation. We have applied a method which consists in the treatment of testicular homogenates by a detergent and subsequent counting of the resistant sperm heads. The results show that both LH administration and copulation are able to produce a significant diminution of the number of spermatozoa contained in the rat testis.

Animals↗
PubMed1973

Copulation in castrated male rats following combined treatment with estradiol and dihydrotestosterone.

Castrated male rats injected daily with 2 micrograms of estradiol benzoate (EB) combined with 200 micrograms of dihydrotestosterone propionate (DHTP) displayed masculine mating behavior which was indistinguishable from that of other castrates treated with 200 micrograms of testosterone propionate (TP). Significantly less copulation was seen in rats treated with either 4 micrograms of TP plus 200 micrograms of DHTP or 2 micrograms of EB. Mating in male rats may depend on the action of both estrogenic and 5alpha-dihydro metabolites of testosterone.

Animals↗
PubMed1986

Inhibition of cell nuclear androgen receptor binding and copulation in male rats by an antiandrogen, Sch 16423.

The ability of the flutamide metabolite Sch 16423 to block androgen receptor binding and inhibit masculine copulatory behavior in male rats was examined. Restoration of copulatory behavior was prevented in Sch 16423-treated rats given two 10-mm testosterone (T)-filled Silastic capsules plus 15 mg Sch 16423 daily for 11 days. Control males receiving only T-filled capsules copulated successfully. To test maintenance of copulatory behavior, T-filled capsules were implanted at the time of castration and rats received daily injections of either 0, 1, 5, 15 or 30 mg Sch 16423. Ejaculation was not prevented by Sch 16423 treatment, suggesting only a weak effect of Sch 16423 on the maintenance of copulatory behavior. An exchange assay was used to determine the effects of Sch 16423 on cell nuclear androgen receptor binding both in vivo and in vitro. For in vivo tests, castrate males bearing two 10-mm T-filled capsules received a single injection of either 0, 1, 5, or 15 mg Sch 16423 1 h prior to sacrifice. Androgen receptor binding was drastically reduced in both brain (combined hypothalamus, preoptic area, amygdala and septum) and pituitary at all doses of Sch 16423. For in vitro assays, samples from brain and pituitary were incubated with 10(-10) to 10(-6) M dihydrotestosterone (DHT), Sch 16423 or flutamide. Sch 16423 competed for androgen receptors in vitro, though not as effectively as DHT. Flutamide was a poor competitor. These results indicate that Sch 16423 effectively reduces masculine copulatory potential primarily affecting restoration of behavior, and that Sch 16423 inhibited cell nuclear androgen receptor binding both in vivo and in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Anilides↗
PubMed1985

Copulation induces an acute increase in epididymal sperm numbers in rats.

The temporal changes in epididymal sperm numbers during the month after sexual contact were examined in 80 adult albino rats. The comparably sexually experienced males in 6 experimental groups were allowed 3 ejaculations with ovariectomized females in which oestrus was induced by hormone injections. Epididymides were removed from the experimental males 1 h, 1 day, 2 days, 3 days, 7 days or 30 days later. Control males were sexually inexperienced or sexually experienced and living with females. Epididymal sperm counts revealed a pattern that resembled an inverted V-shaped function with a peak at 48 h after copulation. We suggest that sexual activity provokes an acute attenuation of sperm disposal within the epididymis with the result that more spermatozoa are available for ejaculation during sexually active times.

Animals↗
PubMed1990

Influence of time of mating and paced copulation on induction of pseudopregnancy in cyclic female rats.

The present experiment was designed to examine whether changes occur during the course of behavioural oestrus in the sensitivity of the female to copulatory stimulation and in patterns of sexual behaviour which might influence the likelihood of luteal maintenance. Cyclic female rats were mated on the evening of pro-oestrus (21:00 h) or early on the morning of oestrus (05:00 h) and received either 5 or 10 intromissions from males under conditions which allowed or did not allow pacing of contacts with males to occur. During mating, the levels of sexual receptivity, the timing of sexual mounts from males, and pacing behaviours were measured. The occurrence of pseudopregnancy or pregnancy in each animal was determined by examining vaginal smears for 14 days after mating and by examining the uterus for the presence of fetuses at the end of the experiment. At both mating times, pacing of copulation with males increased the likelihood of prolonged luteal activity. However, females were more likely to become pseudopregnant following non-paced mating at 05:00 h than at 21:00 h the previous evening. Of those females receiving an ejaculation during mating, no difference were seen between groups in the incidence of pregnancy. This change in sensitivity to cervical-vaginal stimulation during oestrus was not associated with changes in sexual receptivity or pacing behaviour. The ability of cervical-vaginal stimulation to induce pseudopregnancy therefore increases toward the end of the period of oestrus, but the behavioural mechanisms which regulate receipt of such stimulation remain constant during that time.

Animals↗
PubMed1999

Behavior and endocrine changes in high-performing, low-performing, and male-oriented domestic rams following exposure to rams and ewes in estrus when copulation is precluded.

High-performing, low-performing, and male-oriented rams were used to investigate behavior and neuroendocrine correlates of sexual interest and discrimination. Treatment consisted of visual and olfactory contact with stimulus animals through a woven wire fence, which inhibited copulation (either ewes in estrus or other rams), for 4 h on each of three consecutive days. Before exposure to stimulus animals on d 1 and during the final 1 h of exposure on d 2, blood samples were collected every 15 min for 1 h to determine concentrations of LH and testosterone. During exposure to stimulus animals, rams were continuously observed and investigatory behaviors were recorded. There was no day effect for any behavior. Groups of rams differed (P < .05) in amounts of behaviors exhibited, but behaviors were not influenced by sex of stimulus animals. High-performing rams exhibited more (P < .05) investigatory behaviors toward stimulus animals than low-performing or male-oriented rams. Plasma concentrations of LH increased (P < .05) in high-performing rams following exposure to estrous ewes, but not following exposure to rams. In low-performing and male-orientated rams, concentrations of LH were unchanged regardless of sex of the stimulus animal. Change in plasma concentrations of testosterone from pre- to posttreatment did not differ between high-performing, low-performing, and male-oriented rams. However, low-performing rams exhibited an increase (P < .05) in plasma concentrations of testosterone following exposure to rams. In conclusion, high-performing rams exhibit a high degree of investigatory behaviors toward estrous ewes and other rams. High-performing rams seem to discriminate sex of stimulus animals and exhibit a neuroendocrine response (i.e., increased plasma LH) only when exposed to ewes in estrus. The sensory signals provided by estrous females are either not detected by low-performing or male-oriented rams or are not sufficiently provocative to elicit further investigation by these rams.

Animals↗
PubMed1998

Mating in Heliothis virescens: transfer of juvenile hormone during copulation by male to female and stimulation of biosynthesis of endogenous juvenile hormone.

Studies were undertaken to determine whether adult males of Heliothis virescens transfer juvenile hormone (JH) to females during copulation, and an in vitro radiochemical assay was used to determine whether mating causes an allatotropic effect, i.e., stimulation of JH biosynthesis by corpora allata (CA). In vitro, CA from 3-day-old mated females synthesized and released approximately 2.5 times total JH as that of CA from comparably aged virgin females. Of the homologues, JH II exhibited significant increase in mated females; JH I also increased but not significantly. JH III remained similar to that of virgin females. This is the first demonstration of an allatotropic effect of mating in moths. In contrast to the female, CA of virgin males did not produce any JH, but accessory sex glands (ASG) in 3-day-old males synthesized small amounts of JH. Immediately after adult emergence, male ASG contained approximately 1.5 ng JH I and II, which increased by 12 h after emergence and remained at this high level up to 54 h after emergence. JH III was barely detected in ASG. JH in ASG of mated male immediately after uncoupling was depleted almost completely, and 24 h later recovered to levels comparable to that of 54-h-old virgin male. Virgin female bursa copulatrix did not contain any JH, but mated female bursa, immediately after uncoupling, had JH at levels comparable to that observed in virgin male ASG. By 6 h after uncoupling, JH levels decreased dramatically in mated female bursa. These data suggest the transfer of JH to females by the male.

Animals↗
PubMed1997

Fluctuating asymmetry and copulation success in lekking black grouse

In lekking black grouse, Tetrao tetrixmales at the centre of the leks obtain more copulations than males at the edges. We found that males with territories at the edge of the lek obtained fewer matings and also have the most asymmetric tarsi. However, when considering the tail ornament (the lyre) no correlation between asymmetry and mating success was found. Although females are unlikely to select males on the basis of tarsus symmetry, asymmetry in this trait may reflect male condition. We suggest that males in poor condition, as reflected by higher levels of fluctuating asymmetry in the tarsi, do not achieve central positions on the lek arena. This would account for the lower success of males with higher levels of fluctuating tarsus asymmetry.

Journal Article↗
PubMed2000

Male provisioning is negatively correlated with attempted extrapair copulation frequency in the stitchbird (or hihi).

In species with biparental care of offspring and high levels of extrapair parentage, paired males may suffer reduced fitness by investing in offspring that are not their own. In such instances, males are predicted to evolve some form of discrimination between kin and nonkin and vary investment accordingly. One simple form of discrimination is to follow behavioural cues to paternity. We investigated paternal contribution to chick rearing in a socially monogamous population of stitchbirds, Notiomystis cincta, with high levels of extrapair copulation (EPC) and extrapair paternity. The relative contribution of the male to chick provisioning was negatively correlated with attempted EPC frequency. Because the majority of EPC attempts are forced and conspicuous in stitchbirds they are an obvious cue for males to use. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2002

Double copulation of a female with sterile diploid and polyploid males recovers fertility in Bombyx mori.

Silkworm males produce dimorphic sperm, nucleate eupyrene sperm and anucleate apyrene sperm. Apyrene sperm have been speculated to have an assisting role in fertilisation. However, the coexistence of eupyrene and apyrene sperm in the testis and female reproductive organs has made it difficult to define the role of apyrene sperm. Polyploid males are highly sterile. Microscopic observation revealed that the elimination of eupyrene nuclei by peristaltic squeezing caused the sterility of polyploids. Heat-shock applied to pupae of Daizo males (DH) also induced high sterility due to the lack of normal apyrene sperm. When eupyrene sperm of sterile DH males and apyrene sperm of sterile polyploid males were mixed by double copulation, a remarkable increase in fertility of the double-mated females was observed. This finding strongly suggests that the apyrene sperm are indispensable in fertilisation of the silkworm and that polyploid apyrene sperm function as a substitute for diploid sperm. We established an experimental system in which we can separate the two types of sperm for further studies on their functions without chemical and/or mechanical treatments.

Animals↗
PubMed1984

The effect of age, pairing, copulation, and 2-Br-alpha-ergocryptine in the male Mongolian gerbil on the prolactin cells in the anterior pituitary identified by immunocytochemical and Herlant's tetrachrome methods.

Near-adjacent, midsagittal sections of pituitaries of infantile and adult male Mongolian gerbils in several experimental groups (bachelor, paired, tartaric acid-injected, postcopulatory gerbil, and postcopulatory animal injected with 2-bromo-alpha-ergocryptine [CB-154]), were stained by a modification of Herlant's tetrachrome and by the peroxidase-labeled antibody method for prolactin. Cell counts of erythrosinophils and cells immunoreactive for prolactin were made. Sequential staining procedures and thin adjacent sections were used to correlate the staining results. Erythrosinophils were very rare in the infant pituitaries; they increased (P less than .01) in numbers in bachelor pituitaries, remained at the same level (P greater than .05) in paired animals, increased (P less than .01) in the postcopulatory gerbils that were injected with tartaric acid, and increased much less (P less than .05) in postcopulatory males that were injected with CB-154. Prolactin cells were present in modest numbers in infant pituitaries; they increased (P less than .01); in bachelors and reached their highest number in paired animals (P less than .001); they remained unchanged (P greater than .05) in tartaric acid-injected postcopulatory animals but declined (P less than .001) in CB-154-injected, postcopulatory animals. The number of prolactin cells was always significantly greater (P less than .001) than the number of erythrosinophils. Correlative studies revealed the erythrosinophils, some of the light blue cells, and some of the chromophobes gave positive immunocytochemical reactions for prolactin. Apparently, CB-154 inhibited the erythrosinophils and the immunoreactive prolactin cells in the postcopulatory male gerbil, as indicated by a reduction in the number, size, and staining intensity of the cells.

Aging↗