Lie to me to lay with me: Females deceive males via terminal investment.

Historically, males have frequently been portrayed as the manipulative and deceptive gender, while females are often seen as adopting a coy and passive role. In this context, it is proposed that males use a terminal investment strategy, misleading females about their true poor condition, while females passively opt to mate with these deceptive males. However, we hypothesize that females in suboptimal condition may also engage in a terminal investment strategy by mimicking or enhancing their attractiveness to match that of females in better conditions. We studied this hypothesis in Tenebrio molitor, by subjecting females to three varying doses of lipopolysaccharides of Escherichia coli (LPS; 0.25, 0.5, or 1 mg ml-1), or three doses of the pro-oxidant Paraquat (PQ; 20, 40 or 80 mM), and subsequently assessing their survival and attractiveness to males. The LPS treatments and 20 mM of PQ had no significant effect on the survival or attractiveness of the females. However, females treated with 40 or 80 mM PQ survived fewer days compared to the control group. Those injected with 40 mM were more attractive than their control counterparts, while those treated with 80 mM were less attractive. Since the identical doses of LPS, which induce terminal investment in males, had no effect on females, we suggest sexual dimorphism in terminal investment. Furthermore, similar to males, if the stressor reaches a sufficiently high level, the signal becomes honest. These findings highlight how the quantity of stressors influences support for the terminal investment strategy in both males and females. Notably, this study challenges prevailing notions regarding gender roles in sexual selection, indicating that females, not just males, conceal their poor condition to attract mating partners.

Pubertal stress in male rats: Effects on juvenile play behavior and adult sexual partner preference.

Puberty is a period of brain organization impacting the expression of social and sexual behaviors. Here, we assessed the effects of an acute pubertal stressor (immune challenge) on the expression of juvenile play (short-term) and sexual partner preference (long-term) in male rats. Juvenile play was assessed over ten trials at postnatal days (PND) (31-40) with age- and sex-matched conspecifics, and at PND35 males received a single injection of lipopolysaccharide (LPS, 1.5 mg/kg i.p.) or saline. Then, sexual partner preference was assessed at PND 60, 64, and 68, in a three-compartment chamber with a sexually receptive female and a male as potential partners simultaneously. The results confirmed that a single injection of LPS during puberty induced sickness signs indicative of an immune challenge. However, juvenile play was not affected by LPS treatment during the following days (PND36-40), nor was sexual behavior and partner preference for females in adulthood. These findings highlight that, while other studies have shown that LPS-induced immunological stress during puberty affects behavior and neuroendocrine responses, it does not affect juvenile play and sexual behavior in male rats. This suggests a remarkable resilience of these behavioral systems for adaptation to stressful experiences mediated by immune challenges during critical periods of development. These behaviors, however, might be affected by other types of stress.

Cloprostenol effect with and without male stimulation on oestrus synchronization in Peru guinea pigs.

Cloprostenol, a synthetic derivative of prostaglandin F2α, effectively triggers functional and morphological regression of the corpus luteum (luteolysis). In rural Peru, the guinea pig (Cavia porcellus) holds significance within the local economy and serves as a valuable protein source. Enhancing reproductive efficiency is crucial to achieve uniformity in weight, age, and litter size across commercial systems. Thus, our study aimed to evaluate the effect of cloprostenol with and without male stimulation on the onset, duration, and intensity of oestrus in Peru guinea pigs. A total of 128 guinea pigs (120 females and eight males) between 8 and 12 months of age, weighing between 800 and 1200 g, were distributed in cages of 15 females per treatment. Cloprostenol sodium (0 [control], 0.20, 0.25, and 0.30 mg/animal) was IM administered to the groups with and without male stimulation. Four isolated males in individual cages, different from the one used for the treatment, were considered to detect oestrus. The oestrus intensity was assessed by observing sexual behaviour signs such as restlessness, moaning, attempts to mount, pelvic elevation, loin stretching, and vulvar inflammation. The oestrus was manifested 2 days after the administration of cloprostenol sodium. At a dose of 0.30 mg/animal and with male stimulation, the earliest oestrus was observed at 46.9 h. There was a reduction in the oestrus duration (p < .05) in guinea pigs that received the three doses of cloprostenol sodium compared to the control group. The highest percentages of frank oestrus intensity (66.7%) were strongly associated with the administered doses of cloprostenol sodium (p < .01). In conclusion, the cloprostenol sodium administration was proper for rapid oestrus induction in Peru guinea pigs.

Prolactin promotes the recruitment of main olfactory bulb cells and enhances the behavioral exploration toward a socio-sexual stimulus in female mice.

Olfactory communication is triggered by pheromones that profoundly influence neuroendocrine responses to drive social interactions. Two principal olfactory systems process pheromones: the main and the vomeronasal or accessory system. Prolactin receptors are expressed in both systems suggesting a participation in the processing of olfactory information. We previously reported that prolactin participates in the sexual and olfactory bulb maturation of females. Therefore, we explored the expression of prolactin receptors within the olfactory bulb during sexual maturation and the direct responses of prolactin upon pheromonal exposure. Additionally, we assessed the behavioral response of adult females exposed to male sawdust after prolactin administration and the consequent activation of main and accessory olfactory bulb and their first central relays, the piriform cortex and the medial amygdala. Last, we investigated the intracellular pathway activated by prolactin within the olfactory bulb. Here, prolactin receptor expression remained constant during all maturation stages within the main olfactory bulb but decreased in adulthood in the accessory olfactory bulb. Behaviorally, females that received prolactin actively explored the male stimulus. An increased cFos activation in the amygdala and in the glomerular cells of the whole olfactory bulb was observed, but an augmented response in the mitral cells was only found within the main olfactory bulb after prolactin administration and the exposure to male stimulus. Interestingly, the ERK pathway was upregulated in the main olfactory bulb after exposure to a male stimulus. Overall, our results suggest that, in female mice, prolactin participates in the processing of chemosignals and behavioral responses by activating the main olfactory system and diminishing the classical vomeronasal response to pheromones.

Sexual motivation and performance in sexual naïve and experienced rats treated with ivermectin: an ultrasonic vocalization study / Motivação e desempenho sexual em ratos com e sem experiência sexual tratados com ivermectina: um estudo da vocalização ultrassônica

In mammals, ivermectin acts as a GABAA receptor agonist and stimulates GABA release. Previous studies showed that ivermectin (IVM) reduces sexual performance, impairing the latency to the first mount and intromission. These parameters are usually considered motivational parameters of sexual behavior. However, IVM increases GABAergic activity leading to motor incoordination. Thus, it is reasonable to propose that IVM affects sexual performance via motor incoordination pathways. The present study analyzed ultrasonic vocalization in rats to verify whether IVM impairs sexual behavior via motivational mechanisms or motor impairment. Because sexual experience attenuates the impairment of motor performance, rats with sexual experience were also studied. Sexually naive and experienced rats were administered a therapeutic IVM dose and saline. The rats were exposed to receptive females, and the latency to the first mount was evaluated, followed by the 50-kHz USV test. IVM treatment in naïve rats increased the latency to first to mount relative to Saline naïve rats, while no differences were observed between saline and experienced rats. In naïve-IVM rats, a reduced frequency and total calls and increased mean time of calls occur relative to SAL-naïve rats. Experienced IVM rats did not show differences in the frequency, mean, and maximal calls close to Saline experienced rats. However, an increase in the total calls and the dominant frequency of calls were observed in IVM-experienced rats compared to Saline experienced rats. A negative and positive correlation occurred between the latency to the first mount and USVs in groups with and without ivermectin exposure. Hence, we propose that ivermectin increased the sexual motivation of rats exposed to a female in estrous based in USVs despite an increased latency to the first mount that occurred. The increased latency to the first mount resulted from motor incoordination, as previously observed and proposed by our group.(AU)

Em mamíferos, a ivermectina (IVM) atua como agonista do receptor GABAA e estimula a liberação de GABA. Estudos anteriores mostraram que a IVM reduz o desempenho sexual, prejudicando a latência para a primeira monta e intromissão. Esses parâmetros são geralmente considerados parâmetros motivacionais do comportamento sexual. Por outro lado, a IVM aumenta a atividade GABAérgica levando à incoordenação motora. Assim, é possível que a IVM afete o desempenho sexual devido a um impedimento motor. O presente estudo analisou a vocalização ultrassônica em ratos para verificar se a IVM prejudica o comportamento sexual via mecanismos motivacionais ou comprometimento motor. Uma vez que a experiência sexual atenua o comprometimento do desempenho motor, também foram estudados ratos com experiência sexual. Ratos sexualmente inexperientes e experientes foram administrados com uma dose terapêutica de IVM ou solução salina IVM. Os ratos foram expostos a fêmeas receptivas e foi avaliada a latência para a primeira monta, seguida do teste de vocalização ultrassônica (USV) de 50 kHz. O tratamento com IVM em ratos inexperientes aumentou a latência para a primeira monta em relação a ratos inexperientes tratados com solução salina, enquanto não foram observadas diferenças entre ratos experientes tratados com IVM e solução salina. Em ratos inexperientes tratados com IVM ocorreu redução da frequência e total de USVs, bem como aumento do tempo médio de USVs em relação aos ratos sem experiência. Ratos experientes tratados com IVM não mostraram diferenças na frequência, média e máxima das USVs em relação aos ratos experientes tratados com solução salina; no entanto, observou-se aumento no total de USVs e na frequência dominante de USVS em ratos experientes tratados com IVM comparados aos experientes tratados com solução salina. Observou-se correlação negativa e positiva entre a latência para a primeira monta e USVs nos grupos sem e com experiência tratados com IVM, respectivamente. Assim, propomos que a IVM aumentou a motivação sexual de ratos expostos a uma fêmea em estro com base em USVs, apesar de apresentar aumento na latência para a primeira monta. O aumento da latência para a primeira monta foi atribuída à incoordenação motora, conforme observado anteriormente e proposto por nosso grupo.(AU)

Apelin-13 facilitates lordosis behavior following infusions to the ventromedial hypothalamus or preoptic area in ovariectomized, estrogen-primed rats.

In normal hormonal conditions, increased neuronal activity in the ventromedial hypothalamus (VMH) induces lordosis whereas activation of the preoptic area (POA) exerts an opposite effect. In the present work, we explored the effect of bilateral infusion of different doses of the apelin-13 (0.37, 0.75, 1.5, and 15 µg) in both brain areas on the expression of lordosis behavior. Lordosis quotient and lordosis reflex score were performed at 30, 120, and 240 min. Weak lordosis was observed following the 0.37 µg dose of apelin-13 at 30 min in the VMH of EB-primed rats; however, the rest of the doses induced significant lordosis relative to the control group. At 120 min, all doses induced lordosis behavior, while at 240 min, the highest dose of 15 µg did not induce significant differences. Interestingly, only the 0.75 µg infusion of apelin in the POA induced significant lordosis at 120 and 240 min. These results indicate that apelin-13 acts preferably in HVM and slightly in POA to initiate lordosis behavior in estrogen-primed rats.

Sulfasalazine exposure during pregnancy and lactation induces alterations in reproductive behavior in adult female rat offspring.

AIMS: Sulfasalazine (SAS) is the first line drug in the treatment of chronic inflammatory bowel diseases in pregnant women. SAS and its metabolites cross the placenta and can be transferred through the milk. However, the long-term consequences to the reproductive system of offspring from dams exposed to SAS have not yet been studied. Thus, our study investigated the effects of SAS treatment during gestational and lactational periods on maternal care in F0 and reproductive outcomes in F1 females. MAIN METHODS: Wistar female rats (n = 10/group) received 300 mg/kg/day of SAS dissolved in carboxymethyl cellulose (CMC), by gavage, from gestational day 0 to lactation day 21 and 3 mg/kg/day of folic acid during gestation. The control group received CMC only. On PND 21, the female pups were selected for reproductive evaluation at different time points: infancy and adulthood. The reproductive parameters evaluated were installation of puberty (vaginal opening and first estrus), estrous cyclicity, reproductive organs weight, histological analysis of the ovary follicles and uterus, analysis of oxidative stress in ovarian tissue, reproductive behavior (sexual and maternal), and fertility. KEY FINDINGS: SAS treatment decreased the retrieving behavior in F0 females. The F1 females presented an increase in the lordosis score, frequency of lordosis of magnitude 3, and lipid peroxidation of ovarian tissues in both infancy and adult life. SIGNIFICANCE: The SAS effects observed in the current study represent a relevant concern for public health, as they demonstrated that treatment with SAS compromised the maternal motivation of dams and induced reproductive alterations in F1 females.

Behavioral and neurochemical effects in mice after one-generation exposure to low doses of manganese: Focus on offspring development.

The risk of exposure to toxic metals is a known concern to human populations. The overexposure to Mn can lead to a pathological condition, with symptoms similar to Parkinson's disease. Although toxicity of Mn has been reported, studies in neonates are scarce but necessary, as Mn can cross biological barriers. The present study evaluated if chronic perinatal exposure to Mn at low doses lead to neurotoxic effects in mice, after direct and indirect exposure. Couples of mice were exposed to Mn (0.013, 0.13, and 1.3 mg kg-1.day-1) for 60 days prior to mating, as well as during gestation and lactation. The offspring was distributed into two groups: animals that were not exposed after weaning - parental exposure only (PE); and animals subject to additional 60-day exposure through gavages after weaning - parental and direct exposure (PDE). Neurological effects were evaluated by Mn quantification, behavior tests and biochemical markers in the brain. PDE animals had alterations in short/long-term memory and increased anxiety-like behavior. Exposure to Mn triggered a decrease of glutathione-s-transferase and increase of cholinesterase activity in different regions of the brain. These findings highlight the risk of exposure to low doses of Mn over a generation and at early stages of development.

Close-range cues used by males of Polistes dominula in sex discrimination.

Sexual pheromones are chemical molecules responsible for mediating sex recognition and mating events. Long- and close-range sexual pheromones act differently. The first type is released to attract potential partners, whereas the second coordinates the interactions after potential mating partners encounter each other. Cuticular hydrocarbons (CHCs) have been suggested to be important cues in the mating systems of several Hymenoptera species, although empirical data are still lacking for many species. Here, we evaluated whether males of the model species Polistes dominula can differentiate the sex of individuals based on their CHC composition. In August 2019, several post-worker emergent nests (n = 19) were collected in the vicinity of Leuven (Belgium) and taken to the lab (KU Leuven), where newly emerged females and males were sampled, marked individually, and kept in plastic boxes for at least a week before being used in the mating trials. Focal males were paired with females and males from different nests and subjected to five different conditions: (I) alive, (II) dead, (III) CHCs washed, (IV) CHCs partially returned, and (V) CHCs from the opposite sex. We videotaped the interactions for 10 min and analysed the duration and different behavioural interactions of the focal male. Our results indicate that CHCs may be used by males as cues to recognise a potential mating partner in P. dominula, since the focal males displayed specific courtship behaviours exclusively toward females. Although we cannot exclude that visual cues could also be used in combination with the chemical ones, we empirically demonstrate that CHCs may be important to convey sexual information at close range in mating systems, allowing fast decisions toward potential sexual partners or rivals.

Effects of corticosterone treatment and wound healing on reproductive traits of American bullfrogs.

During reproductive season, calling anuran males display high testosterone (T) and episodically high corticosterone (CORT) plasma levels, which are positively associated with higher calling rates and immunocompetence. However, exposure to constant stress stimuli can result in chronically elevated CORT levels, possibly leading to inhibition of reproductive and immune activity. Reproduction and immune responses are energetically expensive, so when an animal is immunologically challenged, a tradeoff might be expressed, with CORT potentially mediating it. Our aim was to test how episodic and chronic CORT treatments, alongside wound healing, would affect reproduction in American bullfrog males (Lithobates catesbeianus). Forty animals were divided in four groups: Episodic CORT (daily transdermic application of CORT), placebo (daily transdermic application of sesame oil), chronic CORT (subcutaneous CORT silastic implants), and sham control (subcutaneous empty silastic implants). One week after treatments began, animals were punctured in the leg with a biopsy needle and the wound was photographed after 45 days to determine wound healing status (WS). Blood samples were collected throughout the experiment to measure CORT and T plasma levels. After animal euthanasia, testes were dissected, fixed, and analyzed histologically to determine spermatogenic activity (germinative cyst [GmC] morphometrics). As expected, the episodic CORT treatment had no effect on T plasma levels or spermatogenic activity. On the other hand, chronic CORT treatment reduced GmC morphometric traits, indicating suppression of reproduction, although T levels were not altered. In addition, animals from sham control and chronic CORT treatments with higher T levels presented higher WS, which indicates an immune-enhancing T effect.

Effects of ethanolic extract of the Cleome arabica on sexual behavior in Wistar rats

Traditional medicinal plants are widely used as immunomodulatory medicines that help improve health. A total of 50 plants used for the treatment of toxicity were screened for their protective effects. Traditional medicinal are globally used and have rapidly grown in economic importance. Intrinsically active compounds are well-known for their antioxidant, anti-tumor, anti-viral, and anti-inflammatory activities. The study was conducted to investigate the effects of the ethanolic extract of C. arabica leaves on sexual behavior in Wistar rats. C. arabica, a medicinal plant with a foul odor, toxic, and hash allucinogenic effects. The experimental study was carried out on white rats (male and female) of the Wistar strain from the Pasteur Institute of Algiers (Kouba, Algeria), weighing between 150 and 200g sexually naive. The animals were raised in polyethylene cages and divided into two groups (n = 10 rats/group), which received a saline solution (male and female control group), 0.20µg/ml of the ethanolic extract of C. arabica leaves for seven days orally (male and female treated group). The sexual behavior test was performed according to three types of crossing. The results of the treated groups showed a significant increase in mating frequency compared to the control group. Overall, the results showed that C. arabica significantly affects sexual behavior. The ethanolic extract of C. arabica increased sexual behavior and orientation activity performance recorded in the treated animals. Thus, this study found that C. arabica has a significant effect on the rats' sexual behavior.

Profile of Terpenoid Compounds Mediating a Plant-Herbivore Interaction: Screening by Static Headspace Solid-Phase Microextraction-Gas Chromatography/Q-ToF Mass Spectrometry.

Conotrachelus dimidiatus (Coleoptera: Curculionidae) interacts with immature guava fruits (Psidium guajava L.) for feed, sleep, mate and oviposit. Determination of the volatile organic compounds (VOCs) emitted by the insect and immature fruits can help improve understanding of plant-insect and intraspecific insect interactions between females and males of C. dimidiatus. Daytime fruit setting emissions of immature guava consist mainly of limonene, caryophyllene, and aromadendrene. In addition to the host's volatiles, the aim of this study was to assess the VOCs released by the insect. Static headspace-solid phase microextraction (SHS-SPME), combined with gas chromatography/quadrupole time of flight mass spectrometry (GC/Q-ToF-MS), allowed the identification of the C10 terpenoids: grandlure I, II, II, IV, grandisoic acid, papayanol and papayanal bioactive compounds released by female and male C. dimidiatus under laboratory conditions. These chemical compounds are candidates for the preparation of a lure formulation.

Tibolone facilitates lordosis behavior through estrogen, progestin, and GnRH-1 receptors in estrogen-primed rats.

A dose-response study was made of the broad-spectrum gonadal steroid agonist tibolone (TBL) on lordosis behavior in estradiol benzoate (EB: 5 µg) primed rats. Doses of TBL (0, 1, 4, and 16 µg) were infused to the right lateral ventricle 2 h before testing. The highest dose increased lordosis quotients significantly at 240 min and 360 min following infusion. However, the intensity of lordosis was weak. In experiment 2, the TBL dose of 16 µg was selected to determine whether tamoxifen (TMX), RU486, or antide could modify the lordosis response to TBL. Infusions of the three compounds, before TBL, significantly attenuated the TBL-induced facilitation of lordosis. The results suggest that TBL stimulates lordosis by activating estrogen, progesterone, and may do so by downstream stimulation of GnRH release. The physiological role TBL plays in controlling lordosis behavior remains to be determined.

Behavior and reproduction of belida fish (Notopterus notopterus, Pallas1769) in different stocking density and nurtured with different types offeed

Belida fish (Notopterus notopterus, Pallas 1769) is one of Indonesia's endemic fish that has high economic value so that the catch is so high and has begun to decline in population from nature. The purpose of this study was to analyze the behavior and reproduction of belida fish that nurtured with stocking density and different types of feed. This study was conducted from April to June 2018 in the Fish hatchery and Breeding Laboratory of Fisheries and Marine Science Faculty, Riau University. The design used is a randomized complete design with stocking density treatment consisting of 5, 10, and 15 tail/m³ and type of feed consisting of pellet + vitamin E feed and trash fish feed (dumbo catfish cubs). The results showed that the best treatment was in the stocking density of 5 tail/m³ and trash fish feed (dumbo catfish cubs) showed aggressive fish behavior in chasing the feed given, resulting in reproductive value consisting of the fish number of gonad maturity (TKG IV) as many as 5 fishes, gonado somatic index value of 0.58%, the fecundity of 6,053 eggs, egg diameter of 2.49 mm and semen volume of 0.045ml.(AU)

Behavior and reproduction of belida fish (Notopterus notopterus, Pallas1769) in different stocking density and nurtured with different types offeed

Belida fish (Notopterus notopterus, Pallas 1769) is one of Indonesia's endemic fish that has high economic value so that the catch is so high and has begun to decline in population from nature. The purpose of this study was to analyze the behavior and reproduction of belida fish that nurtured with stocking density and different types of feed. This study was conducted from April to June 2018 in the Fish hatchery and Breeding Laboratory of Fisheries and Marine Science Faculty, Riau University. The design used is a randomized complete design with stocking density treatment consisting of 5, 10, and 15 tail/m³ and type of feed consisting of pellet + vitamin E feed and trash fish feed (dumbo catfish cubs). The results showed that the best treatment was in the stocking density of 5 tail/m³ and trash fish feed (dumbo catfish cubs) showed aggressive fish behavior in chasing the feed given, resulting in reproductive value consisting of the fish number of gonad maturity (TKG IV) as many as 5 fishes, gonado somatic index value of 0.58%, the fecundity of 6,053 eggs, egg diameter of 2.49 mm and semen volume of 0.045ml.

In utero and lactational exposure to triclocarban: Age-associated changes in reproductive parameters of male rat offspring.

Triclocarban (TCC) is an antimicrobial compound, widely used in personal care products, such as soaps, toothpaste, and shampoo. This agent is incompletely removed by wastewater treatment and represents an environmental contaminant. Studies show that TCC has been associated with some endocrine disruptions. In vitro, TCC demonstrated potent androgen-augmenting activity and aromatase inhibition. In this sense, exposure during critical periods of development (gestation and lactation) could lead to some adverse health outcomes in offspring. Therefore, the present study evaluated if maternal exposure to three different doses of TCC could interfere in the reproductive parameters of male offspring. Pregnant female Wistar rats were separated into four groups: vehicle Control (CTR); TCC 0.3 mg/kg (TCC 0.3); TCC 1.5 mg/kg (TCC 1.5); TCC 3.0 mg/kg (TCC 3.0). Dams were treated daily by oral gavage from gestational day 0 to lactational day 21. The males were evaluated in different timepoint: infancy (PND 21), puberty (PND 50) and adult life (PND 90-120). The histomorphometric analysis of testis and testosterone level were assessed on PND 21, 50, 120; sexual behavior and sperm parameters at adulthood. In the TCC 3.0 group, a decrease in the testis interstitial volume and an increase in testosterone levels were observed on PND 21. Moreover, there was a decrease in the diameter of the seminiferous tubules on PND 50, and a decrease in sexual competency in adulthood. These results suggest that exposure to a human relevant dose of TCC may interfere with reproduction and could have implications for human health.

Nature and nurture of sexual partner preference: Teachings from prenatal administration of acetaminophen in male rats.

The organizational-activational hypothesis indicates that activation of adult sexual behavior in males depends on organization of the masculine brain during the perinatal sensitive period. In the medial preoptic area such masculinization depends on a neuroendocrine cascade that includes exposure to testosterone, aromatization to estradiol, activation of estrogen receptors, synthesis of cyclooxygenase (COX), increase of prostaglandins, release of glutamate, and activation of AMPA receptors that result in the formation of more dendritic spines. Thus, in the present study we assessed the sexual partner preference (SPP) of adult male rats prenatally treated with acetaminophen (APAP), an analgesic/antipyretic drug that inhibits COX-2 and is commonly used and prescribed during pregnancy. Female rats received either saline (2 ml/kg s.c.) or APAP (50 mg/kg s.c.) every 12 h, during days 16-20 of pregnancy. At postnatal day PD60 half of the male offspring were exposed to sexual experience with receptive females during 5 trials, and the other half remained sexually naïve. At PD90 all them were tested for SPP with one sexually receptive female and one stud male. The results indicated that only APAP-naïve males failed to display SPP. However, APAP-experienced males displayed SPP for females. We discuss the effects of prenatal APAP in the disruption of unconditioned responses towards females (nature mechanisms), and the effects of sexual experience (nurture mechanisms) in the development of conditioned heterosexual preference.

Can maternal exposure to paracetamol impair reproductive parameters of male rat offspring?

Paracetamol is a widely used medication during gestation and lactation periods for the treatment of pain and fever. Several studies have shown that exposure to paracetamol can increase the incidence of cryptorchidism and decrease testosterone production. Therefore, the present study aimed to evaluate if maternal treatment with paracetamol during gestation and gestation/lactation periods can alter reproductive and behavioral parameters in male offspring. Female Wistar rats were treated daily by gavage with water or paracetamol (350 mg/kg/day) during gestation (CTRG and PARG) or gestation/lactation periods (CTRGL and PARGL). There were significant differences in histomorphometry (increased volume and total length of the seminiferous tubules) and weight of testes (PARG group) and copulatory behavior and testosterone levels (PARG and PARGL groups) at PND 120. Therefore, the present study showed that maternal exposure to paracetamol has an impact on the reproductive system and sexual behavior of male adult offspring suggesting an impaired in sexual hypothalamic differentiation at the beginning of the development of the brain.

The effects of cannabidiol on male reproductive system: A literature review.

Cannabidiol (CBD) is one of the most abundant phytocannabinoids present in the plant Cannabis sativa (marijuana). There have been several studies of CBD in the last few decades, mainly focused on its neuroprotective properties, particularly after the identification of the endocannabinoid system and its participation in the central nervous system. On the other hand, the peripheral effects of CBD, particularly on reproductive physiology, were also evidenced. A narrative review was conducted using the PubMed database to identify studies that analyzed the pharmacological effects of CBD on the male reproductive system of vertebrates and invertebrates. Thirty-two citations (in vivo and in vitro) were identified. Among the vertebrates, the studies were carried out with men, monkeys, rats and mice. Studies with invertebrates are centered exclusively on the sea urchin. The CBD treatment periods include mostly acute and subacute evaluations. Exposure to CBD is associated with a reduction in mammalian testis size, the number of germ and Sertoli cells in spermatogenesis, fertilization rates, and plasma concentrations of hypothalamic, pituitary and gonadal hormones. Moreover, chronic doses of CBD have impaired sexual behavior in mice. From the studies identified in this review, it is possible to conclude that CBD has negative effects on the reproductive system of males. However, knowledge is still limited, and additional research is required to elucidate fully the mechanisms of action, as well as the reversibility of CBD effects on the reproductive system.

Long-term effects of status epilepticus during infancy in male rats: Sexual behavior and brain response upon exposure to sexually receptive females.

Previous research in female rats showed that induction of status epilepticus (SE) during infancy impairs proceptive sexual behavior at the long run in adulthood but temporarily, since full proceptivity is recovered after four mating trials. In male rats, such equivalent effects have not been explored yet. Thus, SE was experimentally induced by injecting lithium chloride (3 mEq/kg, i.p.) in thirteen-day-old (P13) male pups and then, on P14, pilocarpine hydrochloride (100 mg/kg, s.c.). Controls received the same volume of saline. For Experiment 1, at P90, we analyzed c-Fos immunoreactivity (c-Fos-IR) as a measure of unconditioned brain activity after exposing them to sexually receptive females, but without physical contact. For Experiment 2, a different group of males was tested for locomotor activity, and their sexual behavior was assessed during five trials. Then, serum testosterone and corticosterone levels were measured. Our results showed that a lower proportion of SE males performed mounts, intromissions, and ejaculations, and repeated training did not improve their behavior. The levels of testosterone in SE males were reduced, but corticosterone, c-Fos-IR, and locomotion were similar to controls. These results suggest that SE during infancy impairs adult sexual behavior by reducing testosterone.