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PubMed2003

Reproductive features of the Russian vole in laboratory breeding.

Reproductive features of newly bred Russian voles (Microtus rossiaemeridionalis) as a laboratory animal were studied. This species is a copulatory ovulator, and most couples copulated 6 to 16 h after pairing. The gestation period varied from 18 to 22 days (mean +/- SD: 20.6 +/- 0.9, n = 72), and the average litter size was 4.6 +/- 1.9 (n = 125). Compared with the litter size at the first parturition (3.6 +/- 1.6, n = 72), the litter size in the subsequent parturitions increased to 5.9 +/- 1.4 (n = 53). The animals exhibited postpartum estrus, and repeated pregnancy accompanied with suckling pups and parturition continuously in the laboratory condition unlike other vole species. In view of their complex stomach and good proliferation, the Russian voles were evaluated as a good laboratory animal, especially as a model animal for ruminant studies.

Animals↗
PubMed2004

Thee effect of 5-HTP on the reproductive timer in the male cricket.

The post-copulatory sexually refractory stage in the male cricket Gryllus bimaculatus consists of the two substages: the first refractory stage (RS1, time-variable) between copulation and spermatophore preparation, and the second refractory stage (RS2, time-constant) between spermatophore preparation and the recommencement of courtship. To understand the mechanism of the timer for RS2, subcuticular or intraganglionic injection of biogenic amines (10(-2) mol l(-1)) was performed immediately after spermatophore preparation. RS2 was shortened by octopamine, 5-HT, 5-HTP and NA-5-HT. Among these, 5-HTP was most potent. It shortened RS2 to maximally about 38% of the control. The shortening effect continued for 4.5 h after subcuticular injection even when the hemolymph was washed out with saline at 1 hour after injection. Simultaneous injection of 5-HTP with the inhibitor (NSD-1015) of 5-HT synthesis enzyme nullified the effect of 5-HTP, indicating that the shortening effect was caused by 5-HT synthesized from extrinsic 5-HTP. Injection of the inhibitor (CHX) of protein synthesis had no effect of on RS2. These results suggest that the reproductive timer in the TAG may be controlled by 5-HT or a second messenger mediated by 5-HT.

5-Hydroxytryptophan↗
PubMedDate not supplied

Sexual behaviour and stridulation during mating in Triatoma infestans (Hemiptera: Reduviidae).

Factors affecting mating behaviour in the bug Triatoma infestans were quantitatively studied in the laboratory. Experimental conditions were established so that the probability of copulation increased with the time elapsed since the first adult meal. Copulatory attempts by males did not vary as a function of time, but rejections by females became significantly less frequent with the post feeding time. Non-receptive females displayed four types of rejection behaviour, i.e. flattening, stridulation, evasion and abdominal movements. The occurrence of stridulation performed by females in a sexual context was observed in a regular fashion and was quantified for the first time in this species.

Animals↗
PubMed2001

Experimental transmission of Trypanosoma cruzi through the genitalia of albino mice.

Trypanosoma cruzi is usually transmitted by contact with the excreta of infected Triatominae; among non-vectorial infections, direct transmission through coitus has been proposed. We investigated this possibility by instilling, through the external meatus of the vagina and the penis of previously anesthetized NMRI albino mice, blood of mice infected with strains isolated from Didelphis marsupialis (opossum, strain CO57), Rattus rattus (rat, strain CO22) and human (strain EP). Some animals were allowed to copulate the same day of the instillation. In other experiments, the strains were inoculated in the scrotum. To determine the effect of immunosuppression, some mice were treated with cyclophosphamide 30 days post-instillation. Controls were instilled orally and ocularly. Vaginal instillation with strain CO22 produced systemic infection with tropism to the heart, skeletal muscle, skin, duodenum, pancreas, ovary and sternum. Scrotal inoculation with strain EP likewise invaded liver, spleen, lung, lymph nodes and urogenital organs; while strain CO57 invaded skeletal and cardiac muscle, pancreas, testis, and vas deferens. Penile infection with strain CO22 was detected by xenodiagnosis. Immunosuppression did not increase parasitemia of vaginally infected mice or controls. Mating did not produce infection. Our results show that contact of blood trypomastigotes of T. cruzi with genital mucosa can produce blood and tissue infections. These results are discussed in relation to reports of frequent experimental tropism of T. cruzi toward urogenital organs.

Animals↗
PubMed2002

Attractant volatiles released by female and male Triatoma infestans (Hemiptera: Reduviidae), a vector of chagas disease: chemical analysis and behavioral bioassay.

Volatiles emitted by male and female T infestans before and during copula were collected on Porapak-Q filters, desorbed with dichloromethane, and analyzed by gas chromotography and gas chromatography-mass spectrometry after confirmation of attractiveness in an arena bioassay. Chemical analysis confirmed the presence of (R,S) -2- and 3-methylbutan-1-ol in a 2:1 ratio; short chain acids (ethanoic to nonanoic acid); long chains acids decanoic to (Z)-9-octadecenoic acid; aliphatic aldehydes (hexanal to nonanal), benzaldehyde and dipropylsulphide from insects in copula. Electroantennographic studies conducted with a homologous series of aliphatic aldehydes on female and male T infestans showed that, for a given dose, EAG responses elicited from both sexes increased with increased chain length up to nonanal, after which EAG-activity declined. Attractiveness of non-acidic trace components identified in the volatiles were tested on male and female T. infestans, in an arena bioassay using a video tracking method. Aliphatic C6 to C10 aldehydes were tested: hexanal (1-100 microg) and heptanal (10 microg) were attractive to female T. infestans, high doses of octanal and nonanal (1-100 microg) were Unattractive to male and female T. infestans but low doses of nonanal (0.01-0.1 microg) were attractive to male T infestans. Benzaldehyde was highly attractive to female T. infestans at low doses (0.05- 0.1 microg). 3-methylbutan-1-ol was attractive to male T infestans at high dose (1,000 microg). (S) or (S,R) 2-methyl-butan-1-ol were attractive to males or females (1-1,000 microg). Blends of hexanal and benzaldehyde (20:1 and 40:1) showed an additive effect on attraction compared with hexanal alone, when tested on female T. infestans. The study has demonstrated the presence of a number of electrophysiologically and behaviorally active compounds in volatiles emitted by T. infestans in copula that may have a role in the postulated copulation pheromone.

Animals↗
PubMed2004

Analysis of the copulatory courtship songs of Lutzomyia longipalpis in six populations from Brazil.

The sand fly Lutzomyia longipalpis Lutz & Neiva (Diptera: Psychodidae: Phlebotominae), the main vector of Leishmania infantum in the Americas, is believed to be a species complex, although the status of different Brazilian populations is still somewhat unclear. Preliminary analysis of the acoustic signals that are produced during copulation by L. longipalpis males has suggested the existence of three sibling species in Brazil. In the current report, we analyze in more detail a number of parameters of the copulatory courtship songs of L. longipalpis males from four allopatric populations from different parts of the country (Marajó Island, Natal, Jacobina, and Lapinha Cave) and from two sympatric populations from the locality of Sobral, where two types of males can be differentiated by the number of pale spots (one or two pairs) found on the abdomen. We show that males from the localities of Natal, Marajó, and Sobral (two-spot morph) have very similar songs composed of successive bursts, which are modulated in frequency and amplitude. No significant differences were found in the song parameters of these three populations. In contrast, one-spot males from Sobral and males from Jacobina and Lapinha produce songs that are made of pulses but with distinct patterns for each population and significant differences in all song parameters studied. The results suggest that the L. longipalpis complex in Brazil is composed of four sibling species and that the differences in song patterns between the populations are consistent with the level of divergence found in the period gene.

Animals↗
PubMed1976

Behavioural responses to sex steroids of gonadectomized and sexually regressed quail.

The purpose of these experiments was to compare the behavioural and morphological effects of exogenous sex hormones in gonadectomized quail (Coturnix coturnix japonica) with those in quail having regressed gonads as a result of exposure to short days. In Expt 1, male quail were assigned to one of three treatment groups: (1) intact, exposed to 16 h light: 8 h darkness and injected with oil (group 16L); (2) gonadectomized, exposed to 16 h light: 8 h darkness and injected with 2-5 mg testosterone propionate (TP)/day (group 16L-castrated); and (3) intact, exposed to 8 h light: 16 h darkness, and injected with 2-5 mg TP/day (group 8L). Groups 16L-castrated and 8L responded similarly to testosterone, copulating with equal frequency and rapidity after the same number of days of treatment, and also developing proctodeal (foam) glands of a similar size. Only on day 7 of testosterone treatment did the results for these two groups differ. By day 14, the behaviour of both groups resembled that of the 16L birds. In Expt 2 female quail were assigned to the same three treatment groups, except that the hormone treatment was 25 mug oestradiol benzoate/day. Group 8L became sexually receptive sooner than the 16L-ovariectomized quail, but by day 13 both groups had oviducts of similar size, were equally receptive, and were as receptive as the 16L females. The results suggest that the effects of photoperiod on sexual behaviour in this species are mediated largley, if not wholly , by the gonads. They also suggest exposure to short days and surgical gonadectomy are rather similar experimental procedures in the quail.

Animals↗
PubMed1981

Effects of mating on levels of oxytocin and prolactin in the plasma of male and female rabbits.

The effects of mating on plasma levels of oxytocin and prolactin in male and females rabbits have been investigated. Blood was collected through indwelling cardiac catheters at intervals of 1, 2, 4, 6, 12, 24, 36 and 60 min after mating. In female rabbits additional samples were taken 5h after mating, as well as daily during the ensuing pregnancy or pseudopregnancy. They were also fitted with intrauterine balloons for recording uterine activity. Copulation induced a rapid, transient rise in plasma oxytocin in female rabbits at the same time as a fall in plasma prolactin. Mating or sexual excitement had no significant effect on plasma concentrations of oxytocin or prolactin in bucks. Relatively large fluctuations of plasma oxytocin were seen in male rabbits under normal conditions and after mating, suggesting episodic release of oxytocin in a random fashion. The uterine recordings indicated that, in spite of the modest release of oxytocin, a strong sympathetic adrenal activation occurred in response to mating and this provided the overriding influence on uterine activity. During pregnancy plasma levels of prolactin rose significantly on day 4, and remained raised throughout most of gestation. Plasma prolactin fluctuated widely during the first half of pregnancy but the mean levels were higher than those found during the second half of gestation. When pseudopregnancy was induced with injection of an ovulating dose of LH, plasma prolactin rose in a similar manner as during early gestation or mating-induced pseudopregnancy. Thus, in contrast to rats, stimuli associated with mating have no direct influence on the subsequent release of prolactin in rabbits. The secretion of prolactin during gestation seems to be controlled entirely by ovarian steroids, probably progesterone.

Animals↗
PubMed1991

The epithelium of the rabbit vagina: a microtopographical study by light, transmission and scanning electron microscopy.

In order to obtain a more precise microtopographical surface map of the epithelium of the rabbit vaginal mucosa, investigations by light microscopy (LM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) have been systematically correlated. The epithelium was examined from the "portio vaginalis cervicis uteri" down to the "vestibulum". This study shows that the upper 2/3 of the vagina--which, in this species, is very long, measuring 13-14 cm--is lined by a single epithelial layer of tall ciliated and microvillous cells closely resembling the endocervical epithelium with which it is continuous. Moreover, these ciliated and microvillous cells also cover mucosal infoldings in the upper part of the vagina, especially those on the ectocervix and in the fornices, and scattered vaginal crypts. In particular, the ciliated elements decrease in number below the fornices, so that in large areas of the middle part of the vagina only microvillous cells are recognizable. Prior to the squamo-columnar junction, however, the ciliated cells increase again. This study also reveals that in the rabbit the squamo-columnar junction is located at the level of the pubic symphysis and that a squamous pluristratified epithelium covers only the lower 1/3 of the inner surface of the vaginal wall. In the estrous, i.e., precoital rabbit, the microvillous cells show little sign of secretion, whereas after mating they exhibit remarkable secretory features. These seem to increase progressively with postcoital stages (5 h, 24 h and 10 days) in the form of extensive mucification. These secretions often come in contact with spermatozoa retained in the mucosal infoldings and crypts, and are similar to those occurring in the endometrium, where they clearly depend upon progesterone activity. These epithelial features, different from those of other mammals, including humans, suggest that the greater part of the rabbit vagina accomplishes functions other than serving for copulation and as a fetal passageway. The present findings support the view that the rabbit vagina also plays a role as a reservoir of spermatozoa and in maintaining their viability, like the endometrium and endocervix.

Animals↗
PubMed2002

The force driving mating behavior in the house musk shrew (Suncus murinus).

The mating behavior of the domesticated house musk shrew was observed in detail under laboratory conditions. The observations revealed that the house musk shrew has a series of behaviors before copulation. Tactile, auditory and chemical senses appear to function as flags for the recognition of conspecifics and to promote the development of an interaction between the sexes. The tactile senses and the use of the snout were particularly important in the mating sequence, and mutual contact appeared to give rise to driving the sequence to completion. The two sexes contacted each other 'politely', came to mounting by continuous following, and the male finished with a series of post-ejaculatory offensive behaviors and scent markings. The variation in the contact reduced once the female commenced tail-wagging. The ratio of the time spent in front-and-behind contact to that spent in multi-lateral contact increased when both sexes commenced following formation. This ratio was maintained until the male's post-ejaculatory offensive behavior finished. The series of mating behavior was completed by the continuous touching of both sexes and by changes in the manner of contact.

Animals↗
PubMed1992

Luteinizing hormone and testosterone response of sexually active and inactive rams.

The objective of this study was to identify rams exhibiting high (HP) and low (LP) levels of sexual performance and to determine whether their respective behavioral responses to ewes in estrus were related to changes in serum testosterone (T) and LH concentrations. Rams were selected on the basis of standardized serving capacity tests. Plasma T and LH concentrations in rams were measured in three experiments: 1) after 15 min of exposure to estrous ewes, 2) after an injection of 500 ng of LHRH, and 3) during an 11-h exposure to estrous ewes. During 15 min of exposure to ewes, HP rams were sexually active, whereas LP rams showed no sexual interest. Secretion of LH was similar (P greater than .05) between ram groups. Sexual arousal, copulation, and ejaculation of HP males were not related (P greater than .05) to LH secretion. Exposure to estrous ewes for 11 h, however, stimulated LH pulse frequency and elevated basal LH and T concentrations in HP but not LP rams (P less than .001). Luteinizing hormone secretion was positively correlated to the frequency of mounts (r = .19; P less than .01) and ejaculation (r = .17; P less than .03). Aggressive behavior of rams directed at ewes was negatively correlated to LH (r = -.22 P less than .003). Concentrations of LH and T after LHRH injection were similar between HP and LP rams (P greater than .05). These results show that the effects of the ewe on LH secretion of rams depend on length of the exposure period and sexual activity of the male.

Aggression↗
PubMed1997

An evaluation of three methods for assessing sexual behavior in boars.

This study used three separate methods to evaluate sexual behavior in boars previously classified as having high (H), intermediate (INT), or low (L) levels of sexual behavior. Boars were initially evaluated for sexual behavior at 9.6 to 10.6 mo of age with a tethered female for 5 min. Boars were subsequently evaluated with a tethered female for 10 min (TF), a group of females for 10 min (FG), or continuously in a cohabitation environment for 113 h (C). When boars were evaluated with the TF procedure they mounted the female in less time (P < .01) and copulated sooner (P < .01) than when evaluated with the FG procedure. Regardless of whether the TF or FG procedure was used, L boars cumulated less time (P < .01) nosing the sides of females and took longer (P < .01) to first mount than H or INT boars. Proportion of successful matings was not different between the TF and FG procedure; however, the proportion of successful matings by H (91.7%), INT (79.2%), and L (45.8%) boars did differ (P < .001). With the C procedure, sexual behavior classification affected (P < .01) average number of successful matings (H, 4.7; INT, 2.3; and L, .33). This study indicates that sexual behavior traits expressed by a boar are similar when evaluated with a tethered female, a group of females, or a cohabitation environment.

Animals↗
PubMed2005

Effects of novel females and stage of the estrous cycle on sexual behavior in mature beef bulls.

The objective of this experiment was to determine the effects of unrestrained females on sexual behavior of bulls. Twelve Angus bulls were used in three Latin square replicates where sexual interactions between one bull and one female were quantified for each of four 60-min tests (T1, T2, T3, and T4, respectively). All bulls received the following treatments: 1) exposure to four estrual females in sequence (A-B-C-D); 2) exposure to two estrual females in alternating sequence (E-F-E-F); 3) exposure repeatedly to one estrual female (G-G-G-G); and 4) exposure repeatedly to one diestrous female (CON). During T1, mount interactions, mounts with intromission and mounting intervals were similar when bulls were in A-B-C-D, E-F-E-F, or G-G-G-G. Fewer mount interactions, no mounts with intromission, and increased mounting intervals (P < 0.05) occurred in CON. During T2, there were more mount interactions, more mounts with intromission, and decreased mounting intervals (P < 0.05) when bulls were in A-B-C-D or E-F-E-F compared with when they were in G-G-G-G or CON. More mount interactions (P < 0.05) occurred in G-G-G-G compared with CON, but mounts with intromission and mounting intervals did not differ. During T3, more mount interactions (P < 0.05) occurred in G-G-G-G than in CON; otherwise, sexual behaviors were similar among treatments. Mounting intervals during T3 were similar among A-B-C-D, E-F-E-F, and G-G-G-G, but were all decreased (P < 0.05) compared with CON. During T4, more mount interactions, more mounts with intromission, and decreased mounting intervals (P < 0.05) occurred when bulls were in A-B-C-D compared with other treatments. Mount interactions were similar when bulls were in E-F-E-F, G-G-G-G, or CON; however, more (P < 0.05) mounts with intromission occurred when bulls were in E-F-E-F compared with G-G-G-G or CON. Mounting intervals during T4 were decreased (P < 0.05) in E-F-E-F compared with the CON treatment, whereas in G-G-G-G, they were intermediate. Mounts without intromission were not affected by female novelty or receptivity, but novel females induced more flehmen responses. In conclusion, novel, females, overall, enhanced sexual activity of bulls; however, bull sexual responses diminished after 2 h, even when a novel female was presented. Estrual females that were repeatedly paired with bulls displayed diminished sexual receptivity, but if mated females were rested for 60 min, they allowed further copulation from familiar bulls that were not sexually sated.

Analysis of Variance↗
PubMed2001

Mushroom bodies and post-mating behaviors of Drosophila melanogaster females.

After mating, Drosophila melanogaster females lay substantially more eggs and mate rarely. Central to these changes is Sex peptide (SP), a male peptide transferred into the female during copulation. Injected into virgins, SP induces the same post mating response as observed after mating. In this study we investigated the role of the mushroom body (MB) in the SP response system. The SP response of females with either chemically ablated or mutant MBs was analyzed. After injection of SP, females with chemically ablated MBs reduce their receptivity and increase their ovulation and oviposition to the level of females with intact MBs. Virgin females with ablated MBs, however, show a constitutively elevated oviposition rate. Hence in untreated females, MBs are not implicated in the SP-induced reduction of receptivity and increase of ovulation. However, they depress the oviposition rate of virgins. Thus, SP has two functions for oviposition: it de-represses the MB-dependent block on the egg laying activity of virgins and additionally stimulates oviposition. SP-injected mushroom body miniature (mbm) females lay fewer eggs, ovulate less frequently, and mate more often than wild-type females. A model of the putative role of MBs and the gene product of mbm in SP-induced oviposition is presented.

Animals↗
PubMed1975

Effect of coitus on serum levels of testosterone and LH in male and female rabbits.

Levels of testosterone (T) and LH in the peripheral serum of male and female rabbits were measured and compared following coitus. Blood was collected by heart puncture from restrained, unanesthetized animals of both sexes. In male rabbits, basal serum T levels were highly variable, ranging from 131 to 12,149 pg/ml, and if low preceding coitus they tended to rise; whereas, if high, they usually dropped as they did in nonmated males subjected to repeated heart punctures. In contrast, basal serum LH levels in males were quite constant (mean +/- SE, 1993 +/- 152 pg/ml) and were not significantly altered after coitus unless blood T levels had been drastically lowered by two priming doses of estradiol benzoate. In intact does, on the other hand, copulation which resulted in ovulation induced an approximately 20-fold increase in serum LH concentration which was sustained for about 4 hr. Postcoital elevations in serum LH also occurred in estrogen-primed intact and estrogen-primed ovariectomized does. Under the conditions of our experiments, the parallel elevations in serum LH and T observed postcoitally in the female rabbit could not be demonstrated in the male.

Animals↗
PubMed2005

Behavioral effects of stimulation of the medial amygdala in the male rat are modified by prior sexual experience.

Researchers have found that stimulation of the medial nucleus of the amygdala (MeA) in male rats increases appetitive copulatory behavior directed toward an anestrous female but suppresses copulation with an estrous female (C. P. Stark et al., 1998). The objective in the present study was to determine if the behavioral change produced by stimulation of the MeA was dependent on chemical and/or visual cues from the conspecific. The author reports that electrical stimulation of the MeA in male rats increased the frequency of mounting and investigative behavior directed toward a male conspecific. However, these effects were limited to those subjects that had no prior sexual experience. Results are discussed in terms of possible experience-dependent alterations in neural response patterns within the MeA and related areas.

Amygdala↗
PubMed1996

c-Fos expression as a tool to search for the neurobiological base of the sexual behaviour of males.

Elevated expression of c-fos mRNA and/or its protein (c-Fos) has been repeatedly observed following activation of brain cells with various stimuli. As a consequence it has been proposed that elevated c-fos expression may serve as a marker of neuronal activation reflecting a predisposal to long-term changes in cell functioning (neuronal plasticity). In studies on copulatory behaviour of male animals, elevated Fos immunoreactivity (related most probably to c-Fos) has been used by many researchers as a tool to reveal functional neuroanatomy of the behaviour. They found that brain regions such as medial preoptic area (MPOA), bed nucleus of stria terminalis (BNST), medial amygdala (MeAm) and central tegmental field (CTF) are always activated in a copulation-dependent manner in various species (rats and hamsters were the most often studied in this regard). This paper reviews the data gathered in this field, and discusses them in the context of a role of elevated Fos expression in acquisition vs. performance of the sexual behaviour.

Animals↗
PubMed2000

Stimulation of the medical preoptic area facilitates sexual behavior but does not reverse sexual satiation.

The aim of the present study was to establish whether electrical and/or drug stimulation of the medial preoptic area/anterior hypothalamus (mPOA/AH) surmounts the sexual behavior inhibition that results from copulation to exhaustion. Thus, intermittent electrical stimulation of the mPOA/AH (alone or combined with the systemic injection of yohimbine or apomorphine, at doses that were subthreshold for reversing sexual exhaustion) or intrapreoptic treatments to block GABAergic transmission were applied to sexually satiated rats. The results suggest that the mPOA/AH is not responsible for male sexual behavior inhibition or for the pharmacologically induced sexual behavior expression in satiated rats. Data are discussed in terms of the roles ascribed to the mPOA/AH, both in the control of sexual behavior expression and in the regulation of the postejaculatory interval.

Animals↗