Seminal Plug Research Articles

Tactile stimulation prevents disruptions in male rat copulatory behavior induced by artificial rearing.

Early life social interactions in gregarious mammals provide an important source of stimulation required for the development of species-typical behaviors. In the present study, complete deprivation of maternal and littermate contact through artificial rearing was used to examine the role of early social stimulation on copulatory behavior and the ejaculate in adult rats. We found that artificially reared naïve male rats were sexually motivated; nevertheless, they did not acquire the level of sexual experience that typically occurs during copulatory training. Disrupted expression of sexual experience of artificially reared rats was demonstrated by an inconsistent pattern of ejaculatory behavior across training tests. Artificial tactile stimulation applied during isolation prevented this disruption and rats achieved ejaculation in most copulatory tests. Despite the irregularity of ejaculatory behavior in isolated rats, their sperm count and seminal plug were similar to control maternally reared (sexually experienced) and artificially-reared rats that received tactile stimulation. These results suggest that tactile sensory information provided by the mother and/or littermates to the offspring is crucial for the development of copulatory behavior. The absence of social and/or tactile stimulation during early life compromises the ability of male rats to gain sexual experience in adulthood.

Rats ejaculate prematurely and increase the sperm output during competitive mating

Rats are gregarious and promiscuous and when a female enters the behavioral estrous, two or more males copulate alternately (mount, intromission or ejaculation are performed by any of them). This circumstance promotes male-male competition that in turns influences the copulatory behavior. Thus, olfactory and visual cues of rivals, in laboratory conditions, shorten the ejaculation latency. Other studies focusing in the presence of a rival found the increment in the sperm number. Until now it is unknown if the simultaneous presence of two males simultaneously influences the copulatory performance and seminal characteristics. Thus, the aim of the present work was to evaluate if sexual competition modifies the copulatory behavior, the sperm number and seminal plug. Sexually experienced Wistar rats were tested in two different copulatory contexts. Non-competitive mating (one male-one female), and competitive mating (two males-one female). The copulatory (mounts, intromissions and ejaculation) and seminal parameters (sperm count and copulatory plug) were analyzed. We found that under competition, there was a shortening of the ejaculation latency due to the reduction in the inter-intromission interval and in the number of intromissions. Respect to the ejaculate, the sperm number increased drastically but the seminal plug maintain its size and weight characteristics. Therefore, sexual competition in male rats affects copulatory behavior and sperm count but not the seminal plug.

Acute restraint stress triggers progesterone withdrawal and endometrial breakdown and shedding through corticosterone stimulation in mouse menstrual-like model.

Stress impacts the reproductive axis at the level of the hypothalamus and the pituitary gland, which exert an effect on the ovary. Menstruation is regulated by the hypothalamic-pituitary-ovary (HPO) axis. However, the role of stress in menstruation remains unclear. The objective of this study was to explore the role of stress in endometrial breakdown and shedding, using the pseudopregnant mouse menstrual-like model. Female mice were mated with vasectomized males and labeled day 0.5, upon observation of a vaginal seminal plug. On day 3.5, decidualization was induced in pseudopregnant mice using arachis oil. On day 5.5, pseudopregnant mice with artificial decidualization were placed in restraint tubes for 3 h. The findings indicated that acute restraint stress resulted in the disintegration of the endometrium. While corticosterone concentration in the serum increased significantly due to restraint stress, follicle-stimulating hormone (FSH), luteinizing hormone (LH) and progesterone (P4) levels in the serum decreased significantly. An endometrial histology examination indicated that progesterone implants may rescue P4 decline caused by acute stress and block endometrium breakdown and shedding. In addition, mice were treated with metyrapone, an inhibitor of corticosterone synthesis, 1 h prior to being subjected to restraint stress. Interestingly, metyrapone not only inhibited stress-induced endometrium breakdown and shedding, but also prevented stress-induced reduction of P4, LH and FSH. Furthermore, real-time PCR and western blot showed that mRNA and protein expression of CYP11A1 (cytochrome P450, family 11, subfamily A, polypeptide 1) and steroidogenic acute regulatory protein (StAR), the two rate-limiting enzymes for progesterone synthesis in the ovary, decreased following acute stress. But metyrapone prevented the reduction of StAR expression induced by restraint stress. Overall, this study revealed that acute stress results in an increase in corticosterone, which may inhibit LH and FSH release in the serum and CYP11A1 and StAR expression in the ovary, which finally leads to the breakdown and shedding of the endometrium. These experimental findings, based on the mouse model, may enable further understanding of the effects of stress on menstruation regulation and determine the potential factors affecting stress-associated menstrual disorders.

Somatic innervation contributes to the release of bulbourethral gland secretion in male rats.

In male rats, the bulbourethral glands (Bu-Gs) are the unique accessory sexual glands surrounded by striated musculature. However, until now the role of this musculature was unknown. (i) To characterize the Bu-Gs striated muscular layer in male rats and determine its innervation and response to genital stimulation. (ii) To reveal the role of the Bu-Gs striated musculature in the release of glandular secretion. (iii) To elucidate the effect of bilateral ablation of the Bu-Gs on copulatory behavior and seminal fluid characteristics. Adult Wistar male rats were allocated in three experiments: in Experiment 1, the Bu-Gs striated musculature, innervation and reflex activity were determined by gross anatomy and histological and electrophysiological techniques; electromyographic activity of the Bu-Gs striated musculature was evoked with genital stimulation. In Experiment 2, Bu-Gs were analyzed after copulatory behavior of intact or animals with unilateral transected motor branch of the sacral plexus (MBSP). In Experiment 3, copulatory behavior and spermatobioscopy of males with bilateral ablation of the Bu-Gs or sham surgery were analyzed. The Bu-Gs striated fibers discharged in response to mechanostimulation of the prepuce, glans, and penile-urethra. Innervation of the Bu-Gs striated musculature originated from the MBSP; this nerve also innervates striated penile muscles. Unilateral transection of the MBSP significantly decreased the secretion from the ipsilateral Bu-G to the nerve transection. Bilateral ablation of Bu-Gs did not affect seminal plug formation but decreased semen viscosity. The Bu-Gs striated musculature contributes to expel glandular secretion during sexual intercourse. The somatic control of Bu-Gs secretion is additional to the reported autonomic innervation supplied by the cavernosus nerve, which may underlie the synthesis of secretion as well as contraction of Bu-Gs smooth muscle.

Seminal plugs cost red-sided garter snakes dear

![Figure][1] Female red-sided garter snake with seminal plug. Photo credit: Christopher Friesen. Bubbling out of their hibernation burrows as the temperature begins to rise, male red-sided garter snakes only have one thing on their mind: mating. And with females in short supply, the

Dracaena arborea extracts delay the pro-ejaculatory effect of dopamine and oxytocin in spinal male rats.

Dracaena arborea is a medicinal plant with ethnopharmacological aphrodisiac reputation. In the present study, the effect of an intravenous administration of aqueous and ethanolic extracts from the dried roots of this plant on the ejaculatory pattern of spinal cord-transected and urethane-anaesthetized rats was investigated. In addition, the effects of these extracts were also determined on dopamine and oxytocin-induced ejaculation. Systemic administration of aqueous and ethanolic extracts (5, 20, 60, 100 mg kg(-1)) of D. arborea did not activate fictive ejaculation, whereas dopamine (0.1 μM kg(-1)) and oxytocin (0.5 UI kg(-1)) provoked ejaculation evidenced by the rhythmic contractions of the bulbospongiosus muscles accompanied with penile erection and sometimes with expulsion of the seminal plugs. Pretreatment of spinal rats with D. arborea extracts dose-dependently blocked the pro-ejaculatory activity of dopamine and oxytocin. In conclusion, the present study shows that the bioactive substances present in the extracts of D. arborea inhibit the activity of the bulbospongiosus muscles through the blockade of dopaminergic and oxytocinergic receptors in rats.

Copulation without seminal expulsion: the consequence of sexual satiation and the Coolidge effect

The studies of sexual satiety in male rats under the Coolidge effect indicate that males reassume copulation until ejaculation. Recently, it was demonstrated that sexually satiated males preserve the motor patterns of intromission and ejaculation, also penile erection, but not seminal expulsion. The first aim was to investigate if penile erections displayed by sexually satiated males dislodge the seminal plugs from the vagina and its effect on sperm transcervical transport. The second aim was to determine the recovery time of seminal expulsion after sexual satiety and its optimal ability to induce pregnancy. Results show that during the Coolidge effect males were able to dislodge the seminal plugs deposited by others (experiment 1A) disturbing the sperm transport (experiment 1B) then interfering with pregnancy (experiment 1C). After satiation, the ejaculate parameters recover slowly: it starts after 10 days with the seminal plug formation, and continues with an increase in sperm count in the uterus 15 days post-satiety (experiment 2). Sexually satiated males impregnated only 28% of the females during 15 days of cohabitation, whereas, satiated males that rested for 15 days impregnated 89% of the females (experiment 3). We concluded that males with successive ejaculations remain potential rivals, because they may disrupt the sperm transport of other males. The ejaculate features recovery after sexual satiety is gradual, begins with the secretions of the sex accessory glands and is followed by the sperm count. Full fertility recovery is reached after 15 days of sexual abstinence when males are able to impregnate most females.

Dose-dependent effects of ethanol extract ofSalvia haematodesWall roots on reproductive function and copulatory behaviour in male rats

This study was aimed to investigate the dose-dependent effects of Salvia haematodes Wall roots (SHW) extract on male reproductive function and copulatory behaviour in rats. Sexually mature males were assigned to four groups: control and treated (5, 50 and 300mgkg(-1) day(-1) for 30days). At the end of treatment regimes, the reproductive activity viz. body/organ weights, testicular spermatogenesis, daily sperm production rate (DSP) and epididymal sperm counts, and sexual behaviour including mounting latency (ML), mounting frequency (MF), intromission latency (IL), intromission frequency (IF), ejaculation latency (EL), post-ejaculatory interval (PEI) and penile reflexes (PE) were assessed. Results showed significant increase in body weight (at 300mgkg(-1) ), testis/epididymis weights (at 50 and 300mgkg(-1) ), testicular spermatids, DSP, tubular diameter and epididymal sperm counts (at 50 and 300mgkg(-1) doses) in treated compared with control rats. It also produced dose-dependant changes in sexual behaviour. The 5mgkg(-1) dose of extract increased MF and PE, whereas 50 and 300kg(-1) doses caused significant increase in MF, IF, PE, EL (but less than sildenafil citrate treatment), hit rate and seminal plug weight. It is concluded that SHW extract enhances anabolic activity, testicular function and sexual behavioural performance in a dose-dependant manner.

Urinary and ejaculatory dysfunction induced by denervation of specific striated muscles anatomically related to the urethra in male rats

The purpose of the present study was to determine the contribution of the external urethral sphincter (EUS), the ischiocavernous (IC), or the bulbospongiosus (BS) on the control of micturition, copulatory behavior and semen expulsion in male rats. We hypothesized that the EUS contributes to maintain urinary continence, while all three muscles participate in expulsive urethral functions. In Experiment 1, it was analyzed the effects of bilateral denervation of IC, BS or EUS, or sham surgery, on voiding behavior and urinary parameters measured before surgery and 2 and 10 days post-surgery. In Experiment 2, copulatory behavior and the weight of the seminal plug expelled during ejaculation were recorded before and after sham surgery or bilateral denervation of the aforementioned muscles. Immediately after ejaculation, the animals were anesthetized to confirm the denervation and determine whether seminal material had accumulated in the lower urinary tract. In IC-denervated animals, voiding duration and the number of mounts was increased, and intromission or ejaculation patterns were absent. Denervation of BS induced signs of post-micturition dribble, decreased voiding frequency, increased urine volume and reduced the amount of semen ejaculated. Denervation of EUS induced signs of post-micturition dribble and urinary incontinence, as well as retrograde ejaculation. Striated muscles anatomically related to the urethra contribute differentially to the control of continence and expulsive urethral functions. Damages to the muscles or to their innervation, as may occur during pelvic surgery, would result in sexual and urinary dysfunctions.

Mondia whitei (Periplocaceae) prevents and Guibourtia tessmannii (Caesalpiniaceae) facilitates fictive ejaculation in spinal male rats

BackgroundMondia whitei and Guibourtia tessmannii are used in Cameroon traditional medicine as aphrodisiacs. The present study was undertaken to evaluate the pro-ejaculatory effects of the aqueous and organic solvent extracts of these plants in spinal male rats.MethodsIn spinal cord transected and urethane-anesthetized rats, two electrodes where inserted into the bulbospongiosus muscles and the ejaculatory motor pattern was recorded on a polygraph after urethral and penile stimulations, intravenous injection of saline (0.1 ml/100 g), dopamine (0.1 μM/kg), aqueous and organic solvent plant extracts (20 mg/kg).ResultsIn all spinal rats, urethral and penile stimulations always induced the ejaculatory motor pattern. Aqueous or hexane extract of Mondia whitei (20 mg/kg) prevented the expression of the ejaculatory motor pattern. The pro-ejaculatory effects of dopamine (0.1 μM/kg) were not abolished in spinal rats pre-treated with Mondia whitei extracts. Aqueous and methanolic stem bark extracts of Guibourtia tessmannii (20 mg/kg) induced fictive ejaculation characterized by rhythmic contractions of the bulbospongiosus muscles followed sometimes with expulsion of seminal plugs. In rats pre-treated with haloperidol (0.26 μM/kg), no ejaculatory motor pattern was recorded after intravenous injection of Guibourtia tessmannii extracts (20 mg/kg).ConclusionThese results show that Mondia whitei possesses preventive effects on the expression of fictive ejaculation in spinal male rats, which is not mediated through dopaminergic pathway; on the contrary, the pro-ejaculatory activities of Guibourtia tessmannii require the integrity of dopaminergic system to exert its effects. The present findings further justify the ethno-medicinal claims of Mondia whitei and Guibourtia tessmannii.

Sperm count and sperm motility decrease in old rats

Sexual behavior declines with age in male rats. The rate and magnitude of this decline may depend on the amount of prior sexual experience and a number of other, unidentified factors. Age-dependent changes in the characteristics of ejaculate quality in rats have not been described earlier, and the relationship between such changes and modifications of sexual behavior is likewise unknown. We have recently developed a technique for the detailed analysis of parameters of ejaculate in rats, and this technique was used for the determination of semen and seminal plug characteristics in rats of different ages. Sexually experienced Wistar rats were tested for sex behavior at the ages of 3, 12 and 24months. Semen was obtained from the female partner immediately after ejaculation at these tests. Between tests, the males were offered the opportunity to copulate once every 3–4weeks. The behavioral data showed that the latency to ejaculation was increased only at 24months. Concerning the characteristics of semen, there was a substantial increase in the proportion of immobile spermatozoa and motility of those moving was much reduced, both at 12 and 24months of age. There was no relationship between parameters of sexual behavior and those of the ejaculate. Likewise, the size of the seminal plug did not affect the amount of intrauterine spermatozoa. The reduced sperm number together with the increased sperm immobility diminishes the ejaculate quality of old males, which could influence fertility.

Copulation and ejaculation in male rats under sexual satiety and the Coolidge effect

Sexually satiated males cease copulating after several ejaculations with the same female; and the presence of an unknown receptive female renews copulation including ejaculation, a process named the Coolidge effect. It is believed that the Coolidge effect has the aim to impregnate another female, although it is known that the sperm count gradually decreases after consecutive ejaculations. The main goal was to investigate if sexually satiated males during the Coolidge effect can reestablish seminal expulsion associated to the ejaculation behavior and/or penile erection associated to the intromission behavior. The results show that during the Coolidge effect, most of the sexually satiated males showed the motor ejaculatory behavior, however, no sperm in the uterine horns or seminal plug in the vagina were detected. Such lack of sperm was not related with the number of ejaculations required to achieve sexual satiety nor with the number of intromissions needed for ejaculating (experiment 1: 2.4.1.). After the behavioral ejaculation, during the Coolidge effect, there was a 44% decrease in sperm count in the epididymal caudae (experiment 1: 2.4.2.). Males that mated for 8 behavioral ejaculations (close to sexual satiety) deposited tiny seminal plugs but no sperm in the female reproductive tract (experiment 1: 2.4.3.). Interestingly, sexually satiated and non-satiated-animals displayed similar number of intromissions and spent a similar time in dislodging the seminal plug from the vagina deposited by other males (experiment 2). These results suggest that sexually satiated males during the Coolidge effect have the capacity for penile erection and vaginal insertion, because they are able to dislodge seminal plugs; but are unable to expel seminal fluid, because neither form seminal plugs nor deposit sperm in the female genital tract.

Investigation of the Effects of α1‐Adrenoceptor Antagonism and L‐Type Calcium Channel Blockade on Ejaculation and Vas Deferens and Seminal Vesicle Contractility In Vitro

Premature ejaculation is one of the most common male sexual dysfunctions. Current pharmacological treatments involve reduction in penile sensitivity by local anesthetics or increase of ejaculatory threshold by selective serotonin reuptake inhibitors. α1-Adrenoceptors (α1-ARs) and L-type calcium channels are expressed in the smooth muscles of the male reproductive tract, and their activations play an important role in the physiological events involved in the seminal emission phase of ejaculation. To evaluate if the inhibition of the contractility of the vas deferens and seminal vesicle by α1-AR antagonism or the L-type calcium channel blockade can delay ejaculation. The effects of the α1-AR antagonist tamsulosin and of the L-type calcium channel blockers, nifedipine and (S)-(+)-niguldipine, on contractions induced by norepinephrine in the rat vas deferens and seminal vesicles in vitro and on the ejaculation latency of male rats in behavioral mating tests were evaluated. Tension development of vas deferens and seminal vesicles in response to norepinephrine in vitro and behavioral mating parameters were quantified. Tension development of vas deferens and seminal vesicle to α1-AR activation was significantly inhibited by tamsulosin, nifedipine, and (S)-(+)-niguldipine. Tamsulosin displayed insurmountable antagonism of contractions induced by norepinephrine in the rat vas deferens and seminal vesicle. Ejaculation latency of male rats was not modified by tamsulosin, nifedipine, or (S)-(+)-niguldipine; however, both the number and weight of the seminal plugs recovered from female rats mated with male rats treated with tamsulosin were significantly reduced. Seminal emission impairment by inhibition of vas deferens or seminal vesicle contractility by L-type calcium channel blockade or α1-AR antagonism is not able to delay the ejaculation.

Rat dorsal prostate is necessary for vaginal adhesion of the seminal plug and sperm motility in the uterine horns.

The rat prostate comprises dorsal, ventral and lateral lobes that are morphologically and biochemically distinct. Lesions to these structures are expected to affect the quality of the ejaculate and male fertility. In experiment 1, we analyzed ejaculate parameters of males that had chemical lesions of the dorsal or ventral lobes. At pre-lesion and at 5 and 20 days post-lesion males were mated, and after ejaculation, seminal fluid and seminal plug were obtained from the mated females. In experiment 2, the ventral lobes were ablated, and the ejaculate was analyzed. In experiment 3, the fertility of males with chemically-lesioned dorsal lobes or ablation of the ventral lobes was evaluated. Chemical lesion of the dorsal lobe prevented the adhesion of the seminal plug to vaginal walls. When these males were tested at 5-days postlesion, no sperm were found in uterus, and at 20-days post-lesion, the few sperm encountered showed slow progressive motility. None of the females that mated with dorsal lobe-lesioned males became pregnant. However, chemical lesion or ablation of the ventral lobes did not affect ejaculate or fertility. Our results indicate that the dorsal prostatic lobes are indispensable for reproductive success in males, and define parameters of ejaculate with which fertility can be estimated.

Rat dorsal prostate is necessary for vaginal adhesion of the seminal plug and sperm motility in the uterine horns

The rat prostate comprises dorsal, ventral and lateral lobes that are morphologically and biochemically distinct. Lesions to these structures are expected to affect the quality of the ejaculate and male fertility. In experiment 1, we analyzed ejaculate parameters of males that had chemical lesions of the dorsal or ventral lobes. At pre-lesion and at 5 and 20 days post-lesion males were mated, and after ejaculation, seminal fluid and seminal plug were obtained from the mated females. In experiment 2, the ventral lobes were ablated, and the ejaculate was analyzed. In experiment 3, the fertility of males with chemically-lesioned dorsal lobes or ablation of the ventral lobes was evaluated. Chemical lesion of the dorsal lobe prevented the adhesion of the seminal plug to vaginal walls. When these males were tested at 5-days postlesion, no sperm were found in uterus, and at 20-days post-lesion, the few sperm encountered showed slow progressive motility. None of the females that mated with dorsal lobe-lesioned males became pregnant. However, chemical lesion or ablation of the ventral lobes did not affect ejaculate or fertility. Our results indicate that the dorsal prostatic lobes are indispensable for reproductive success in males, and define parameters of ejaculate with which fertility can be estimated.

Increased serotonin concentration and tryptophan hydroxylase activity in reproductive organs of copulator males: a case of adaptive plasticity

Individual male rats may systematically display or not copulatory behavior when paired with receptive females. Although these phenotypes are associated with differences in brain organization and function, they might also do so at the level of the reproductive organs. We then used high performance liquid chromatography to quantify serotonin concentration and the activity of tryptophan hydroxylase in the reproductive organs of copulator and non-copulator males. Sexual behavior display was compared between groups and parameters of fertility and reproductive fitness were determined for copulator males. Copulator males had higher concentrations of serotonin in the epididymis, testicle and ventral prostate than their non-copulator counterparts, as it was found for epididymal and testicular tryptophan hydroxylase activity. However, preliminary data shows that serotonin elevation occurs in copulator males only until they have accumulated several sexual encounters, so it might be a response to genital gratification or sexual rewarding. Interestingly, only epididymal serotonin concentration correlated with reproductive fitness, offspring number, mating success and seminal plug volume in copulator males. Our results support that copulator and non-copulator male rats feature a phenotype-specific serotoninergic tone in the epididymis, testicle and ventral prostate gland. The observation documenting that epididymal serotonin concentration correlated with parameters that monitor male fertility and reproductive fitness in copulator males predicts that epididymal factors increase their chances of parenting offspring.

Repeated intermittent methylenedioxymethamphetamine exposure protects against the behavioral and neurotoxic, but not hyperthermic, effects of an MDMA binge in adult rats

We have recently shown that chronic intermittent exposure of adolescent rats to 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) completely blocks the reduction in serotonin transporter (SERT) binding and the hypoactivity seen following a subsequent MDMA binge treatment. The present study determined whether a similar neuroprotective effect also occurs in rats given the same intermittent MDMA exposure in adulthood. Adult male Sprague-Dawley rats were given either MDMA (10 mg/kg x 2) or saline, every fifth day, from postnatal day (PD) 60 to PD 85. The MDMA-induced latency until seminal plug production was reduced over the course of intermittent treatments. After a 1-week wash-out period, animals received either a low- or high-dose MDMA binge (2.5 or 5.0 mg/kg x 4). Core body temperature was measured during and after the binge to determine the effects of MDMA pretreatment on MDMA-induced hyperthermia. Spontaneous motor activity was determined the next day, and cortical and hippocampal samples were collected at 1 week postbinge to measure serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations as well as [3H]citalopram binding to SERT. Hyperthermia occurred more rapidly and seminal discharge was more common in the MDMA-pretreated group compared to the MDMA-naïve group in animals given the low-dose binge. MDMA preexposure protected animals from the reductions in cortical 5-HT levels and SERT binding produced by the high-dose binge and blocked the postbinge hypoactivity. These findings indicate that chronic, intermittent MDMA exposure in adulthood induces neuroprotective effects similar to those seen with adolescent treatment. However, there was also evidence for drug-induced sensitization in adults that was not observed in adolescents. Thus, altered drug sensitivity in chronic Ecstasy users may depend not only on the frequency and pattern of use but also on the age of the user.

Increase of ejaculatory capacity by systemic administration of the oquichpatli ( Senecio cardiophyllus) aqueous crude extract in male rats

Aim of the study To analyse the pro-ejaculatory properties of the proverbial Mexican plant oquichpatli, Senecio cardiophyllus, in an animal model for the study of ejaculation in spinal and anaesthetised male rats. Materials and methods The aqueous crude extract of Senecio cardiophyllus (at 0.4, 1.2 and 4 mg/kg) was i.v. administered to (a) anaesthetised and spinalised male rats after spinal cord transection and (b) anaesthetised and spinalised male rats previous to the inhibition of ejaculation elicited by repeated urethral stimulation. The motor pattern of ejaculation and the development of its inhibition were analysed under the influence of the aqueous crude extract of Senecio cardiophyllus and compared to urethrally induced ejaculations. Results Systemic administration of the Senecio cardiophyllus aqueous crude extract, at all tested doses, induced the ejaculatory response in male rats. This response was featured by a statistically significant augmented number of ejaculatory discharges when compared to control animals. Oquichpatli-induced ejaculatory responses included the expression of autonomic and motor components of ejaculation and the potent expulsion of urethral contents and seminal plugs. Administration of oquichpatli aqueous crude extract prevented the inhibition of ejaculation elicited by urethral stimulation by promoting a statistically significant increase in the expression of ejaculatory motor patterns. Conclusion Present findings show by the first time that the aqueous crude extract of Senecio cardiophyllus possesses the ability to increase the ejaculatory capacity in male rats.

Evaluation of the excopula ejaculatory potentials of Bersama engleriana in spinal male rats

The aim of this study was to investigate the effects of Bersama engleriana and its potential mechanism on fictive ejaculation in spinal male rats. The electromyographic activities of the bulbospongiosus muscles were recorded in spinal cord transected and urethane-anesthetized rats treated intravenously with aqueous (100 mg kg(-1)) and methanolic (100 mg kg(-1)) extracts from the dried leaves of B. engleriana in the absence and presence of dopamine (0.1 micromol kg(-1)) or oxytocin (0.5 UI kg(-1)). Mechanical stimulations of the urethra were also carried out 5 min after the sequential treatments. A single intravenous administration of aqueous (100 mg kg(-1)) and methanolic (100 mg kg(-1)) extracts of B. engleriana did not activate fictive ejaculation. The electromyography recorded after the application of the plant extract was similar to that obtained after intravenous saline injection (200 Gl min(-1)) with no contraction of the bulbospongiosus muscles. Dopamine (0.1 micromol kg(-1)) and oxytocin (0.5 UI kg(-1)) induced rapid rhythmic contractions (P < 0.001) of the bulbospongiosus muscles accompanied by penile erection and sometimes with expulsion of the seminal plugs. Pre-treatment of rats with the two plant extracts completely abolished the occurrence of ejaculation induced by dopamine (0.1 micromol kg(-1)) and oxytocin (0.5 UI kg(-1)). Mechanical stimulation of the urethra carried out 5 min after the sequential treatments always induced penile movements and erections. The inhibitory effect of B. engleriana extracts on the expression of fictive ejaculation in spinal male rat is mediated through dopaminergic and oxytocinergic pathways. This prolonged ejaculatory latency caused by B. engleriana could support its potential use in patients with rapid ejaculation.

Absence of the tail in female rats disrupts the copulatory pattern of experienced male partners

Diverse factors such as sex hormones and sensory stimulation, mainly of the perigenital region, influence sexual behaviour of both Wistar male and female rats, Rattus norvegicus. The tail in rats provides important sensory and propioceptive information, which suggests that this part of the body could be relevant during sexual performance. We analysed the repercussion of the absence of the tail on male and female sexual behaviour. In experiment 1, the lack of the tail in males (caudotomized group) did not affect their copulatory parameters. In comparison with sham and intact groups, they correctly executed the copulatory pattern and deposited the seminal plug into the vagina. Thus, the sensory information given by the tail in males was not relevant for their sexual performance. In experiment 2, the lack of the tail in females did not affect the lordosis quotient in comparison with control females, but it did alter copulatory parameters of male partners with tails. Although caudotomized females were as attractive as control females, males that mated with caudotomized females performed more mounts, and fewer intromissions, and they had lower intromission rates, longer latencies to ejaculation, longer interintromission intervals and longer postejaculatory intervals than males that mated with control females. These results suggest that the female tail stimulates the perineal area of males, facilitating male copulatory performance, because males that mated with caudotomized females had reduced sexual performance.