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PubMed2002

An anatomical and electrophysiological study of the genitofemoral nerve and some of its targets in the male rat.

Anatomical descriptions of the genitofemoral nerve (GFn) innervating the lower pelvic area are contradictory. Here we re-examine its origin and innervation by its various branches of principal target organs in the male rat. Using gross dissection, electrophysiological techniques and retrograde tracing of motoneurones with horseradish peroxidase, we confirm that the GFn originates from lumbar spinal nerves 1 and 2, and that at the level of the common iliac artery it divides into a lateral femoral and a medial genital branch. In contrast to previous studies, we report that the genital and not the femoral branch innervates the abdominal-inguinal skin, and not only the genital but also the femoral branch innervates the cremaster muscle (Cm) surrounding the testes. Motoneurones innervating the Cm proper are located in the ventral nucleus of L1 and L2, and those innervating the muscular transition region of the rostral Cm are located in the ventral nucleus in L1 and the ventrolateral nucleus in L2. The GFn may contribute to male reproductive performance by transmitting cutaneous information during copulation and, via contraction of the Cm to promote ejaculation, the protective displacement of the testes into the abdominal cavity during fighting and as a sperm-protecting thermoregulatory measure.

Abdomen↗
PubMed2003

Effect of gestational nicotine treatment on newborn rat retina: a histopathological and morphometric analysis.

BACKGROUND: Smoking is a significant risk factor in several debilitating and fatal diseases. It has been implicated in bilateral tobacco-toxic and Leber's hereditary optic neuropathies. Although it has been demonstrated that smoking has a cumulative effect on retinal and optic nerve functions and causes diffuse and localised retinal sensitivity decrease in healthy chronic heavy smokers, the affected retinal layer has not been identified and there is no experimental study investigating the effect of nicotine exposure during gestation on the newborn rat retina. PURPOSE: This experimental investigation evaluated histologically the influence in vivo of maternal nicotine treatment during pregnancy on the newborn rat retina. Different dosages of the test compound simulated the range of low, moderate, and heavy smokers in humans. METHODS: Experimentally naive, adult female Wistar-albino rats weighing 200-250 g were mated with adult male rats over 2 days for copulation in the proportion of two females for every male animal. After confirming pregnancy with vaginal smear method, 40 gravid rats (dams) were then randomly assigned into four equal groups (three experimental and one control; n = 10 in each). On day 9 of gestation, groups 1, 2, and 3 experimental dams were treated with intraperitoneal (i.p.) (-)-nicotine tartrate at doses of 0.5, 1, and 2 mg kg body weight-1 day-1, respectively during pregnancy from gestational day 9-21. Group 4 control dams were given i.p. saline solution daily for the same period. After normal delivery, the newborn litters were sacrificed at postnatal day 1 or day 30. The eyes were enucleated for histopathologic and morphometric analysis of the retinas. Nicotine-induced neuronal changes were measured by morphometric analyses on cell counts of ganglion cell layer (linear cell density in number per unit length of retina) and thickness of the various retinal layers. RESULTS: The litters in control group 4, and experimental groups 1 and 2 had normal retinal findings. On the other hand, morphometric analysis of retinal sections in experimental group 3 eyes demonstrated a 20.7% decrease in the number of surviving ganglion cells (40.7 +/- 2.0) compared with controls (51.3 +/- 1.1; p < 0.001). The thickness of whole retina (126.6 +/- 5.4 microm) was also reduced by 13.5% compared with controls (146.3 +/- 4.5 microm; p = 0.007). The main site of retinal atrophy was the inner plexiform layer (30.1 +/- 1.6 microm vs 43.5 +/- 1.3 microm; p < 0.001) with almost no change in the other retinal layers. CONCLUSIONS: Gestational nicotine treatment induces marked changes in the organisation of the developing retina in newborn rats histopathologically. Quantitative morphometric analysis clearly demonstrated that the two most affected structures were the retinal ganglion cells and the inner plexiform layer, both of which are supplied by central retinal artery.

Animals↗
PubMedDate not supplied

Multiple origins of a major novelty: moveable abdominal lobes in male sepsid flies (Diptera: Sepsidae), and the question of developmental constraints.

Contrary to the impression given by their extreme scarcity among extant species of flies, moveable processes on the abdomen are apparently of relatively simple developmental origin, and they have evolved multiple times in males of the small family Sepsidae. They are used to stimulate the female during copulation in two groups, where they are probably independently derived. Because female cuing of reproductive decisions on particular types of stimuli will tend to favor male abilities to elaborate such stimuli, sexual selection by female choice may sometimes result in sustained selection for certain types of innovations in males. The lack of moveable appendages in most dipterans may be due not to developmental constraints, but to lack of selective advantages.

Animals↗
PubMedDate not supplied

Embryonic development of mouse external genitalia: insights into a unique mode of organogenesis.

The mammalian external genitalia are specialized appendages for efficient copulation, internal fertilization and display marked morphological variation among species. In this paper, we described the embryonic development of mouse genital tubercle (GT), an anlage of the external genitalia utilizing the scanning electron microscope (SEM) analysis. It has been shown that the Distal Urethral Epithelium (DUE) may fulfill an essential role in the outgrowth control of the GT. Our present SEM analysis revealed a small distal protrusion at the tip of the GT of normal embryos as well as some morphological differences between male and female embryonic external genitalia. Previous analysis shows that the teratogenic dose of Retinoic Acid (RA) induces a drastic marformation of the urethral plate, but not gross abnormalities for GT outgrowth. Interestingly, a small distal protrusion at the tip of GT was clearly observed also after RA treatement. Furthermore, we showed that treatment with anti-androgen flutamide resulted in the demasculinization of the GT in males. The unique character of GT development and the sexual dimorphism are discussed.

Animals↗
PubMed2003

Influence of testosterone on the electrical properties of scrotal nerves at the cutaneous and spinal levels in the male rat.

The scrotal nerves in the rat were studied electrophysiologically to describe their topographic organization in the skin and in the dorsal roots, and to determine if the electrical properties of these afferents are under the influence of testosterone. There are 2 afferent nerve branches innervating this area, the proximal scrotal branch supplying the proximal half of the scrotum (PSb), and the distal scrotal branch supplying the distal half (DSb). Results showed that afferent axons from PSb enter the spinal cord through the L5 and L6 dorsal roots, and axons from DSb enter the cord through the L6 and S1 dorsal roots. Mechanical stimulation of the scrotal skin exposed 3 dermatome areas, the L5, L6, and S1, with L6 being the longest dermatome with intermingled terminals from PSb and DSb. Decreased levels of testosterone after castration increased the threshold to trigger the activity of scrotal afferents, and the exogenous administration of the hormone reverted it. This effect was similar in the dorsal penile nerve. The decrease in androgen levels produced a reduction in the skin sensory field to mechanical stimuli that was restored after the administration of the hormone. As the scrotal nerves are highly stimulated during copulation in parallel with the dorsal penile nerve, it is suggested that the sensory field of the scrotal skin could be closely related to the modifications in sexual behavior after testosterone manipulation.

Animals↗
PubMed2001

Molineus torulosus (Nematoda, Trichostrongylina, Molineoidea) a parasite of Neotropical primates: new morphological and histological data.

Molineus torulosus (Molin, 1861) parasite of Cebus spp. from South America is redescribed in Cebus apella and C. olivecaeus (new host) from French Guyana with emphasis on the synlophe. During the maturation process, the larvae dwelt in the cysts carved alongside the external part of the small intestine. The turn-out of the mature worms and the laid eggs depended on the tissular organisation of cyst walls as the inflammatory process waned and fibrosis progressed to seal the cystic lumen. Adult worms entwine themselves in the cysts, live there permanently as their presence has never been evidenced in the intestinal lumen. They copulated, laid eggs, degenerated and died once entrapped by the fibrotic process. Laid eggs released in the intestinal lumen through a narrow channel ensured the continuation of the developmental cycle. However, erratic migration was possible via the vascular channels surrounding the cysts.

Animals↗
PubMed2004

[Laparoscopic hernioplasty by transabdominal preperitoneal approach].

INTRODUCTION: Despite the increasing acceptance of the TAPP-procedure by patients and general practitioners this method has to be further examined. In addition to the classic surgical criteria of examination, subjective aspects of patient comfort must be taken into consideration as they are getting more and more significant for the evaluation of different methods. METHODS: According to this objective patients were clinically examined and questioned about specific topics of quality of life after TAPP-operations. Furthermore, the patients documentation (medical report/OP-report) was evaluated retrospectively. RESULTS: Between1995 and 1998 endoscopic transabdominal preperitoneal hernioplasty was used for 267 inguinal hernia repairs in 204 patients. 155 patients could be interviewed about the operative outcome and 199 operated inguinal hernias could be examined physically and sonographically. The recurrence rate was 2.5 %, the rate of major complications was 4.4 %. Postoperative pain-syndrome were found as a major complication in only two cases (1.3 %), postoperative nervous disorders could be diagnosed in 3.5 % of the patients. Further subjective complaints were seen in 19 % of the patients. The median postoperative period until the resumption of sexual intimacy was approximately two weeks, but six male patients reported about long-lasting pain in copulation (3.9 %). DISCUSSION: With regard to the aspects mentioned above, the TAPP-procedure provided exellent results in the examined patient cohort and therefore turned out to be at least comparable with competitive methods. Nevertheless, the postoperative pain in sexual activity that a few male patients complained of represents a new aspect which has to be further investigated.

Adolescent↗
PubMed2005

[Laparoscopic hernioplasty by total extraperitoneal approach].

INTRODUCTION: Despite the increasing acceptance of the TEP-procedure by patients and general practitioners this method has to be further examined. In addition to the classic surgical criteria of examination, subjective aspects of patient comfort must be taken into consideration as they are getting more and more significant for the evaluation of different methods. METHODS: According to this targets patients were clinically examined and questioned about specific topics regarding their quality of life after TEP-surgery and evaluated prospectively. RESULTS: Between 1995 and 2000 endoscopic total extraperitoneal hernioplasty (TEP) was used for 200 inguinal hernia repairs in 195 patients. 195 patients could be interviewed about the operation's outcome and examined physically and sonographically after 3 months, 188 patients after 6 months and 184 patients after 12 months post-op. The recurrence rate was 1.7 %, the rate of major complications was < 1 %. Sensitivity disorders were found in 7.3 % of all cases at the final examination prior to discharging but none at the 3 months check-up. The median postoperative period until the resumption of sexual intimacy was approximately two weeks, but one male patient reported about long-lasting pain in copulation (0.51 %). DISCUSSION: With regard to the aspects mentioned above, the TEP-procedure provided excellent results in the examined patient cohort and therefore turned out to be at least comparable with competitive endoscopic methods. A remarkable new finding was that patients could go back to work on average 2 weeks earlier than regaining their everyday fitness.

Activities of Daily Living↗
PubMed2003

Distribution of spermatozoa in the outer perivitelline layer from above the germinal disc of emu and ostrich eggs.

In the present study, we determined the distribution of spermatozoa in the perivitelline layer above the germinal disc (GD) of emu and ostrich eggs that had been laid at random intervals after mating. Eggs were opened, the perivitelline layer overlying the GD region was collected and sperm were visualized with 4',6'-diamidino-2-phenylindole under a fluorescence microscope. To map the distribution of sperm, the GD was divided into six areas (A-F), with A being the centre of the GD and F the area furthest from the centre. In both species, more spermatozoa were found in areas B, C and D than in areas A, E and F. More than half the GD spermatozoa were found in areas B, C and D. The pattern of distribution of spermatozoa across the GD depended on the total number of sperm in the GD. In the emu, the pattern was related to delay since last copulation and time of laying, whereas in the ostrich the pattern was related to the month of the season and the sex ratio of the mating system. When the total number of spermatozoa in the GD increased, the number of spermatozoa increased in every area of the GD, but the centre and the outer areas were the least affected. We conclude that sperm numbers are highest in a band immediately around the centre of the GD and then decline with increasing distance from the centre. The low numbers in the centre of the GD may be due to either low attractiveness of the centre for sperm or high attractiveness of the area immediately adjacent to the centre.

Animals↗
PubMed2000

Hormonal profiles in the tammar wallaby, Macropus eugenii, following FSH/LH superovulation.

This study investigated the effect of superovulation with exogenous porcine FSH/LH on the normal hormonal milieu of the tammar wallaby (Macropus eugenii). During seasonal and lactational quiescence, groups of 6 females were treated with either multiple doses of porcine follicle-stimulating hormone (FSH) (8 x 6 mg i.m., 12 h apart) followed by a single subcutaneous injection of 4 mg porcine luteinizing hormone (LH) on Day 5 or saline. Blood samples were collected throughout each 10-day experimental period and each female was examined twice daily for signs of a recent copulation. On Day 9, females were killed and their reproductive tracts removed for examination and flushed for eggs. During both seasonal and lactational quiescence, treatment with porcine FSH/LH induced circulating concentrations of progesterone, porcine FSH and porcine LH that were within the normal range of the natural tammar oestrous cycle. However, higher plasma oestradiol concentrations (30-50 microg mL(-1)) than would be expected in a natural tammar preovulatory rise and the presence of 'highly stimulated' ovaries in several of the treated animals suggests that some degree of over-stimulation was occurring. During both seasonal sampling periods, behavioural oestrus was detected in treated tammars in the absence of a withdrawal of progesterone. This data suggests that plasma progesterone is not the critical factor inducing behavioural oestrus.

Animals↗
PubMed1991

Effects of medroxyprogesterone acetate (MPA) on myometrial activity in unmated rats: a study in vivo using video-laparoscopy.

Unmated female rats received medroxyprogesterone acetate (MPA) on the day of oestrus. Myometrial activity in vivo was quantified by video-laparoscopy 24-96 h later. Changes induced by MPA resembled those in early pregnancy/pseudopregnancy, but were not as extreme. There was a significant increase in circular contractions, followed by a decline, as in mated rats. Increases in circular contractions propagating caudally were as large as in mated rats, but increases in those propagating cranially were much smaller and qualitatively different. MPA induced only small increases in the frequency of longitudinal contractions propagating cranially, whereas large increases occurred in pregnancy/pseudopregnancy. We conclude that in early pregnancy/pseudopregnancy, increased circular activity is induced by rising progesterone levels. However, progesterone alone does not account for the increased contractions propagating cranially in mated rats. We suggest that these are induced by increased pacemaker activity in the region of the cervix, possibly activated by stimuli received during copulation.

Animals↗
PubMed2000

Polygyny, mate-guarding, and posthumous fertilization as alternative male mating strategies.

Alternative male mating strategies within populations are thought to be evolutionarily stable because different behaviors allow each male type to successfully gain access to females. Although alternative male strategies are widespread among animals, quantitative evidence for the success of discrete male strategies is available for only a few systems. We use nuclear microsatellites to estimate the paternity rates of three male lizard strategies previously modeled as a rock-paper-scissors game. Each strategy has strengths that allow it to outcompete one morph, and weaknesses that leave it vulnerable to the strategy of another. Blue-throated males mate-guard their females and avoid cuckoldry by yellow-throated "sneaker" males, but mate-guarding is ineffective against aggressive orange-throated neighbors. The ultradominant orange-throated males are highly polygynous and maintain large territories; they overpower blue-throated neighbors and cosire offspring with their females, but are often cuckolded by yellow-throated males. Finally, yellow-throated sneaker males sire offspring via secretive copulations and often share paternity of offspring within a female's clutch. Sneaker males sire more offspring posthumously, indicating that sperm competition may be an important component of their strategy.

Animals↗
PubMed2004

Two feeding-induced proteins from the male gonad trigger engorgement of the female tick Amblyomma hebraeum.

Most female ixodid ticks, once mated, feed to repletion within 6-10 days. Previous studies indicate that an engorgement factor (EF), passed to the female during copulation, may be the stimulus for engorgement. Here, we show that extracts of the testis/vas deferens of fed (but not unfed) male Amblyomma hebraeum contain EF bioactivity when injected into the hemocoel of feeding virgins. We have produced recombinant proteins (recproteins) from 28 feeding-induced genes in the male gonad and have identified a recombinant A. hebraeum engorgement factor (recAhEF) among these recproteins. recAhEF is a combination of two peptides, recAhEFalpha (16.1 kDa) and recAhEFbeta (11.6 kDa), neither of which has bioactivity on its own. recAhEF also stimulates salivary gland degeneration and partial development of the ovary, suggesting that it may be the same material as another male gonadal protein from this tick, male factor. We propose the name "voraxin" for the natural EF of ticks. When normal mated females were put on a rabbit immunized against recAhEF, 74% failed to feed beyond one-tenth the normal engorged weight within 14 days whereas all mated ticks put on a control rabbit engorged normally (mean duration of 8.8 +/- 0.8 days). This result constitutes preliminary evidence that an anti-tick vaccine might be developed from voraxin.

Amino Acid Sequence↗
PubMed2001

Male fertility defects in mice lacking the serine protease inhibitor protease nexin-1.

Understanding infertility and sterility requires knowledge of the molecular mechanisms underlying sexual reproduction. We have found that male mice deficient for the gene encoding the protease inhibitor protease nexin-1 (PN-1) show a marked impairment in fertility from the onset of sexual maturity. Absence of PN-1 results in altered semen protein composition, which leads to inadequate semen coagulation and deficient vaginal plug formation upon copulation. Progressive morphological changes of the seminal vesicles also are observed. Consistent with these findings, abnormal PN-1 expression was found in the semen of men displaying seminal dysfunction. The data demonstrate that the level of extracellular proteolytic activity is a critical element in controlling male fertility.

Amyloid beta-Protein Precursor↗
PubMed2001

Traumatic insemination and sexual conflict in the bed bug Cimex lectularius.

The bed bug, Cimex lectularius, has a unique mode of copulation termed "traumatic" insemination [Carayon, J. (1966) in Monograph of the Cimicidae, ed. Usinger, R. (Entomol. Soc. Am., Philadelphia), pp. 81-167] during which the male pierces the female's abdominal wall with his external genitalia and inseminates into her body cavity [Carayon, J. (1966) in Monograph of the Cimicidae, ed. Usinger, R. (Entomol. Soc. Am., Philadelphia), pp. 81-167]. Under controlled natural conditions, traumatic insemination was frequent and temporally restricted. We show for the first time, to our knowledge, that traumatic insemination results in (i) last-male sperm precedence, (ii) suboptimal remating frequencies for the maintenance of female fertility, and (iii) reduced longevity and reproductive success in females. Experimental females did not receive indirect benefits from multiple mating. We conclude that traumatic insemination is probably a coercive male copulatory strategy that results in a sexual conflict of interests.

Animals↗
PubMed2002

Conditional disruption of synaptic transmission induces male-male courtship behavior in Drosophila.

It is reported here that male-male courtship behavior is evoked instantaneously in the fruit fly Drosophila by conditional disruption of synaptic transmission. A temperature-sensitive allele of the Drosophila dynamin gene shibire (shi(ts1)) was expressed by using the GAL4/UAS system to disrupt synaptic transmission from GAL4-positive neurons in a temperature-dependent manner. An enhancer-trap GAL4 line C309 directing shi(ts1) expression in central and peripheral neurons (C309/UAS-shi(ts1)) initiated stereotypical precopulatory behavior toward other mature males immediately after a temperature shift from the permissive to restrictive temperature. At the restrictive temperature, C309/UAS-shi(ts1) males formed "courtship chains" and exhibited abnormally high levels of head-to-head interactions. The temperature-induced male-male courtship is attributable not to an increase in sexual attractiveness but to an increase in sexual activity of C309/UAS-shi(ts1) males. Interestingly, the temperature-induced increase in sexual activity is specific toward male partners, because C309/UAS-shi(ts1) males courted receptive virgin females less vigorously and copulated less efficiently after shifted to the restrictive temperature. Among the GAL4-positive neurons in C309, conditional disruption of certain cholinergic neurons but not the mushroom body intrinsic neurons plays a critical role in the induction of male-male courtship. These neurons may be involved in inhibitory systems that normally suppress aberrant male-male courtship. The presented strategy that can induce behavioral abnormalities by disrupting synaptic transmission in an acute and noninvasive manner will allow further exploration as to how distinct neuronal groups control sexual orientation and other aspects of reproductive behavior in Drosophila.

Alleles↗
PubMed1969

Dysfunctional sperm production in Drosophila melanogaster males homozygous for the segregation distorter elements.

Drosophila males heterozygous for the segregation distorter chromosome show a reduction in fecundity which is correlated with the degree of distortion of their segregation ratio. When males are made homozygous for the segregation distorter elements, their fecundity is lowered to just that extent expected if each SD were independently causing the sperms carrying the other to dysfunction. In three cases tested, Sd Ac/Ac, Sd Ac/Sd Ac, and Sd Ac St/Sd Ac St, the fecundity of the males is consistent with the dysfunction model, whereas the females are normal. The Sd Ac St/Sd Ac St males are almost completely sterile. They do produce sperms, however, which are motile and which look morphologically normal in the phase contrast microscope. They are transferred to the female during copulation and are stored in apparently normal numbers in the seminal receptacle and spermathecae.

Animals↗