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The largely binary nature of biological sex and its conflation with the socially constructed concept of gender has created much strife in the last few years. The notion of gender identity and its differences and similarities with sex have fostered much scientific and legal confusion and disagreement. Settling the debate can have significant repercussions for science, medicine, legislation, and people's lives. The present review addresses this debate though different levels of analysis (i.e., genetic, anatomical, physiological, behavioral, and sociocultural), and their implications and interactions. We propose a rationale where both perspectives coexist, where diversity is the default, establishing a delimitation to the conflation between sex and gender, while acknowledging their interaction. Whereas sex in humans and other mammals is a biological reality that is largely binary and based on genes, chromosomes, anatomy, and physiology, gender is a sociocultural construct that is often, but not always, concordant with a person' sex, and can span a multitude of expressions.
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Identidade de Gênero , Humanos , Masculino , Feminino , Comportamento Sexual/psicologia , Caracteres SexuaisRESUMO
The neuropeptide kisspeptin (Kiss) is crucial in regulating the hypothalamic-pituitary-gonadal axis. It is produced by two main groups of neurons in the hypothalamus: the rostral periventricular region around the third ventricle and the arcuate nucleus. Kiss is the peptide product of the KiSS-1 gene and serves as the endogenous agonist for the GPR54 receptor. The Kiss/GPR54 system functions as a critical regulator of the reproductive system. Thus, we examined the effect of intracerebroventricular administration of 3 µg of Kiss to the right lateral ventricle of ovariectomized rats primed with a dose of 5 µg subcutaneous (sc) of estradiol benzoate (EB). Kiss treatment increased the lordosis quotient at all times tested. However, the lordosis reflex score was comparatively lower yet still significant compared to the control group. To investigate receptor specificity and downstream mechanisms on lordosis, we infused 10 µg of GPR54 receptor antagonist, Kiss-234, 5 µg of the progestin receptor antagonist, RU486, or 3 µg of antide, a gonadotropin-releasing hormone-1 (GnRH-1) receptor antagonist, to the right lateral ventricle 30 min before an infusion of 3 µg of Kiss. Results demonstrated a significant reduction in the facilitation of lordosis behavior by Kiss at 60 and 120 min when Kiss-234, RU486, or antide were administered. These findings suggest that Kiss stimulates lordosis expression by activating GPR54 receptors on GnRH neurons and that Kiss/GPR54 system is an essential intermediary by which progesterone activates GnRH.
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Estradiol , Kisspeptinas , Receptores LHRH , Receptores de Progesterona , Comportamento Sexual Animal , Animais , Kisspeptinas/farmacologia , Kisspeptinas/metabolismo , Feminino , Comportamento Sexual Animal/efeitos dos fármacos , Comportamento Sexual Animal/fisiologia , Receptores LHRH/antagonistas & inibidores , Receptores LHRH/metabolismo , Ratos , Estradiol/farmacologia , Estradiol/análogos & derivados , Receptores de Progesterona/metabolismo , Receptores de Progesterona/efeitos dos fármacos , Receptores de Progesterona/antagonistas & inibidores , Ovariectomia , Ratos Wistar , Progesterona/farmacologia , Antagonistas de Hormônios/farmacologia , Postura/fisiologia , Receptores de Kisspeptina-1/metabolismo , Mifepristona/farmacologiaRESUMO
RATIONALE: Alcohol can disrupt conditioned sexual inhibition (CSI) established by first-order conditioning in male rats. CSI can also be induced using second-order conditioning, during which male rats are trained to associate a neutral odor with a nonreceptive female. As a result, when given access to two receptive females (one scented and one unscented) during a copulatory preference test, they display CSI toward the scented female. OBJECTIVE: The present study examined the effect of low-to-moderate doses of alcohol on CSI and brain activation following exposure to alcohol and the olfactory cue alone. METHODS: Sexually-naïve Long-Evans rats received alternate conditioning sessions with unscented receptive or scented (almond extract) non-receptive females. Following the conditioning phase, males were injected with saline, alcohol 0.5 g/kg or 1 g/kg, 45 min before a copulatory test with two receptive females, with one bearing the olfactory cue. Fos activation was later assessed, following exposure to alcohol and the olfactory cue alone, in several brain regions involved in the expression and regulation of male sexual behavior. RESULTS: While males in the saline group displayed sexual avoidance towards the scented female, those injected with alcohol before the copulatory test, regardless of the dose, copulated indiscriminately with both females. Subsequent exposure to alcohol and the olfactory cue alone induced different Fos expression between groups in several brain regions. CONCLUSIONS: Low to moderate doses of alcohol disrupt conditioned sexual inhibition in male rats and induce a differential pattern of neural activation, particularly in regions involved in the expression and regulation of sexual behavior.
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There is growing evidence that endocrine disruptive chemicals have deleterious effects on sexual and reproductive function. To examine subjective sexual functions in human females and their relationship to postnatal phthalate exposure and perinatal androgenization, a Sexuality Score (SS) was established from a first-stage survey questionnaire of subjective sexual function filled out by female university students (n = 68; average age 25.23 ± 5.17 years; rural 25.51 ± 6.74 vs. urban 25.85 ± 1.43 years). Seventeen phthalate metabolites in urine samples were analyzed by high-performance liquid chromatography (HPLC) and tandem mass spectrometry (MS/MS). Females were also assessed for the 2D:4D digit ratio as an index of perinatal androgenization. The mean age of menarche was 12.82 ± 1.35 years (rural 12.59 ± 1.39 vs. urban 13.18 ± 1.27; p = 0.01). The mean age at first sexual intercourse was 14.88 ± 6.89 years (rural 14.62 ± 7.20 vs. urban 15.24 ± 6.55), and as the age of first sexual intercourse increases, the SS score tends to increase as well, albeit moderately (r = 0.25, p = 0.037). Mono-iso-butyl phthalate, mono(2-ethyl-5-carboxypentyl) phthalate, mono(hydroxy-n-butyl) phthalate, mono(2-ethyl-5-oxohexyl) phthalate (p ≤ 0.05) and mono(2-carboxymethylhexyl) phthalate (p ≤ 0.01) were negatively associated with SS. A compounding butterfly effect of prenatal exposure to androgens was observed with disruptive effects of mono(2-ethyl-5-oxohexyl) phthalate and mono(2-ethyl-5-carboxypentyl) phthalate on sexual function. Exposure to phthalates in adult females may lead to disruption of subjective sexual function, especially concerning sexual desire and sexual satisfaction, and perinatal androgenization could augment these effects.
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INTRODUCTION: The addition of compulsive sexual behavior disorder (CSBD) into the ICD-11 chapter on mental, behavioral, or neurodevelopmental disorders has greatly stimulated research and controversy around compulsive sexual behavior, or what has been termed "hypersexual disorder," "sexual addiction," "porn addiction," "sexual compulsivity," and "out-of-control sexual behavior." OBJECTIVES: To identify where concerns exist from the perspective of sexual medicine and what can be done to resolve them. METHODS: A scientific review committee convened by the International Society for Sexual Medicine reviewed pertinent literature and discussed clinical research and experience related to CSBD diagnoses and misdiagnoses, pathologizing nonheteronormative sexual behavior, basic research on potential underlying causes of CSBD, its relationship to paraphilic disorder, and its potential sexual health consequences. The panel used a modified Delphi method to reach consensus on these issues. RESULTS: CSBD was differentiated from other sexual activity on the basis of the ICD-11 diagnostic criteria, and issues regarding sexual medicine and sexual health were identified. Concerns were raised about self-labeling processes, attitudes hostile to sexual pleasure, pathologizing of nonheteronormative sexual behavior and high sexual desire, mixing of normative attitudes with clinical distress, and the belief that masturbation and pornography use represent "unhealthy" sexual behavior. A guide to CSBD case formulation and care/treatment recommendations was proposed. CONCLUSIONS: Clinical sexologic and sexual medicine expertise for the diagnosis and treatment of CSBD in the psychiatric-psychotherapeutic context is imperative to differentiate and understand the determinants and impact of CSBD and related "out-of-control sexual behaviors" on mental and sexual well-being, to detect forensically relevant and nonrelevant forms, and to refine best practices in care and treatment. Evidence-based, sexual medicine-informed therapies should be offered to achieve a positive and respectful approach to sexuality and the possibility of having pleasurable and safe sexual experiences.
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Transtorno do Comportamento Sexual Compulsivo , Comportamento Sexual , Humanos , Transtorno do Comportamento Sexual Compulsivo/diagnóstico , Transtorno do Comportamento Sexual Compulsivo/terapia , Classificação Internacional de Doenças , Transtornos Parafílicos/diagnóstico , Transtornos Parafílicos/terapia , Saúde SexualRESUMO
Although women and men rate their subjective arousal similarly in response to "female-centric" erotic videos, women rate their subjective arousal lower than men in response to "male-centric" videos, which often end with the male's ejaculation. This study asked whether ratings of subjective sexual arousal and desire using the Sexual Arousal and Desire Inventory (SADI) would be altered if this ending was present or absent, and whether including or excluding the accompanying soundtrack would influence the magnitude and direction of the responses. A total of 119 cis-gendered heterosexual undergraduates (59 women and 60 men) viewed an 11-min sexually explicit heterosexual video that ended with a 15-s ejaculation scene. Two versions of the video were created, one with the ejaculatory ending (E+) and one without (E-). Participants were assigned randomly to view one of the two versions with (S+) or without (S-) the accompanying soundtrack, after which they completed the state version of the SADI. Women and men found both sequences without sound less arousing on the Evaluative, Motivational, and Physiological subscales of the SADI relative to the S+ sequences. However, on the Negative/Aversive subscale, women found the E + S- sequence more negative than did men, whereas this difference was not found with sound. Thus, women and men were sensitive to the auditory content of sexually explicit videos, and scenes of sexual intercourse ending with explicit ejaculation increased the Evaluative and Motivational properties of subjective sexual arousal and desire. However, this occurred in women only when the auditory cues signaled a clear and gratifying sexual interaction.
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Sinais (Psicologia) , Excitação Sexual , Humanos , Masculino , Feminino , Comportamento Sexual , Libido , Heterossexualidade , Literatura EróticaRESUMO
Perinatal testosterone, or its metabolite estradiol, organize the brain toward a male phenotype. Male rodents with insufficient testosterone during this period fail to display sexual behavior and partner preference for receptive females in adulthood. However, cohabitation with non-reproductive conspecifics under the influence of a D2 agonist facilitates the expression of conditioned partner preference via Pavlovian learning in gonadally intact male rats. In the present experiment, three groups of neonatal PD1 males (N = 12/group) were either gonadectomized (GDX), sham-GDX, or left intact and evaluated for social preferences and sexual behaviors as adults. We then examined whether the effects of GDX could be reversed by conditioning the males via cohabitation with receptive females under the effects of the D2 agonist quinpirole (QNP) or saline, along with the size of some brain regions, such as the sexually dimorphic nucleus of the preoptic area (SDN-POA), suprachiasmatic nucleus (SCN), posterior dorsal medial amygdala (MeApd) and ventromedial hypothalamus (VMH). Results indicated that neonatal GDX resulted in the elimination of male-typical sexual behavior, an increase in same-sex social preference, and a reduction of the area of the SDN-POA. However, GDX-QNP males that underwent exposure to receptive females in adulthood increased their social preference for females and recovered the size in the SDN-POA. Although neonatal GDX impairs sexual behavior and disrupts partner preference and brain dimorphism in adult male rats, Pavlovian conditioning under enhanced D2 agonism ameliorates the effects on social preference and restores brain dimorphism in the SDN-POA without testosterone.
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Área Pré-Óptica , Caracteres Sexuais , Gravidez , Ratos , Animais , Masculino , Feminino , Área Pré-Óptica/metabolismo , Encéfalo , Quimpirol/farmacologia , Castração , Testosterona/farmacologia , Testosterona/metabolismoRESUMO
RATIONALE: Cabergoline (CAB) is an ergot derivative typically prescribed for the treatment of hyperprolactinemia. It suppresses the release of prolactin through agonist actions on dopamine (DA) D2 receptors; however, it possesses binding affinity for other DA and 5-HT receptors. Side effects that exacerbate valvular heart disease can occur with high doses. OBJECTIVE: The present study examined the acute, subchronic, and chronic dose-response effects of CAB and a derivative dimethylcabergoline (DMC) which acts as an antagonist instead of agonist at 5-HT 2B receptors, on appetitive and consummatory sexual behaviors of male rats. METHODS: CAB (0, 0.03, 0.15, or 0.3 mg/kg/ml) was administered daily to sexually experienced male rats (N = 10/dose) by oral gavage for a total of 68 days. Sexual behavior was tested every 4 days during this period for a total of 16 trials. On the 17th trial, rats were administered their dose of CAB, and 4 h after were overdosed with sodium pentobarbital, perfused intracardially, and their brains processed for Fos immunohistochemistry. DMC (0, 0.03, 0.15, 0.3 mg/kg/ml) was administered daily to sexually experienced male rats (N = 10/dose) by oral gavage for a total of 36 days. Sexual behavior was tested every 4 days for a total of 9 trials. RESULTS: CAB increased anticipatory level changes, intromissions, and ejaculations significantly across all timepoints, with the medium and high doses being most potent. The medium and high doses also increased Fos protein significantly within the medial preoptic area, whereas in the nucleus accumbens shell, the low and medium doses decreased Fos protein but the high dose increased it significantly from control. Similar to CAB, the medium and high doses of DMC increased the number of ejaculations significantly. Rats in all drug dose groups appeared healthy for the duration of the experiments. CONCLUSIONS: Both CAB and DMC facilitate ejaculations, and CAB further facilitates measures of anticipatory sexual motivation and intromissions. These data suggest that both could be used as treatments for sexual arousal disorders and ejaculation/orgasm disorders with little or no untoward side effects at low doses.
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Copulação , Comportamento Sexual Animal , Ratos , Masculino , Animais , Cabergolina/farmacologia , Motivação , Encéfalo , Hormônios Esteroides Gonadais , Receptores de Dopamina D2RESUMO
Autism spectrum disorder (ASD) is a psychiatric disorder with severe behavioral consequences and no specific therapy. Its etiology is multifactorial, as it is caused by a complex interaction of genetic and environmental factors. In rats, prenatal exposure to the antiepileptic drug valproic acid (VPA) has been associated with an increased risk of autistic-like behaviors in offspring, including social behavior deficits, increased repetitive behaviors, and cognitive impairments. In addition, VPA-treated rats have shown altered sociosexual behaviors. However, the mechanisms underlying these alterations in reproductive processes in VPA-treated rats are not fully understood. Interestingly some abnormal behaviors in VPA autism models are improved by an enriched environment (EE). In the present study, we examined the effects of EE on memory performance and sexual behavior in male rats. We found that on postnatal day 90, EE reduced the time it took for both control and VPA-treated groups to find a hidden platform in the Morris water maze. On PND 100, prenatal exposure to VPA reduced total exploring time in object recognition tests. On PND 110, EE reduced mount and intromission latency and increased ejaculatory frequency in VPA-treated male rats. These results suggest that environmental stimuli significantly influence the onset of sexual behavior in VPA-treated male rats and that EE may be a potential tool for improving a variety of behavioral deficiencies in rodent models of autism.
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Transtorno do Espectro Autista , Transtorno Autístico , Efeitos Tardios da Exposição Pré-Natal , Humanos , Gravidez , Feminino , Ratos , Masculino , Animais , Ácido Valproico/efeitos adversos , Transtorno Autístico/induzido quimicamente , Transtorno do Espectro Autista/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Comportamento SexualRESUMO
The present study investigated the participation of the nitric oxide pathway in facilitating lordosis behavior induced by intrahypothalamic administration of apelin-13 in ovariectomized rats primed with estradiol benzoate (EB). The experiments involved the administration of a nitric oxide synthase inhibitor (L-NAME) or a nitric oxide-dependent, soluble guanylyl cyclase inhibitor (ODQ), and an inhibitor of protein kinase G (KT5823) to the ventromedial hypothalamus (VMH) of EB-primed rats 30 min before infusion of apelin-13 (0.75 µg/µl). This dose of apelin-13 consistently induces lordosis behavior at 30 min, 120 min, and 240 min following infusion. Results showed that injections of either L-NAME or KT5823 significantly reduced the lordosis induced by apelin at 120 and 240 min. However, VMH infusion of ODQ 30 min before apelin-13 infusion reduced but did not significantly inhibit, the lordosis elicited by this peptide at the same time points. We conclude that the nitric oxide pathway in the VMH plays an important role in lordosis induced by apelin-13 in EB-primed rats.
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Lordose , Óxido Nítrico , Ratos , Feminino , Animais , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/metabolismo , Lordose/induzido quimicamente , Comportamento Sexual Animal/fisiologia , Estradiol/farmacologiaRESUMO
INTRODUCTION: Synchronous behaviors between individuals are nonverbal signs of closeness and common purpose. In the flow from initial attraction to intimate sexual interaction, attention and synchrony move from distal to proximal to interactive and are mediated by sensitized activation of neural systems for sexual motivation, arousal, and desire and those that recognize and mimic common facial and body movements between individuals. When reinforced by sexual pleasure and other relationship rewards, this results in the strengthening of attraction and bonding and the display of more common motor patterns. As relationships falter, nonverbal behaviors likely become asynchronous. OBJECTIVES: To define behavioral, romantic, and sexual synchrony during phases of attraction and how their disruption can be observed and utilized by clinicians to assess individual relationship styles and quality. METHODS: We review the literature on behavioral and attentional synchrony in humans and animals in an effort to understand experiential and innate mechanisms of synchrony and asynchrony and how they develop, as well as implications for attraction, relationship initiation, maintenance of romantic and sexual closeness, and relationship disintegration. RESULTS: Evidence is presented that behavioral synchrony and the neural mechanisms that underlie it are vital to relationship formation and satisfaction. CONCLUSION: Behavioral synchrony helps to create feelings of sexual and romantic synergy, cohesion, and arousal among individuals. Asynchrony is aversive and can spark feelings of discontent, aversion, and jealousy. Thus, observing patterns of nonverbal sexual and romantic synchrony between individuals offers insights into the potential quality of their relationships.
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Corte , Parceiros Sexuais , Animais , Humanos , Encéfalo , Emoções , MotivaçãoRESUMO
RATIONALE: Exposure to rewards can alter behavioral reactivity to them. For example, stimulants sensitize locomotor activation, whereas sexual experience sensitizes copulatory behaviors. Moreover, rewards can cross-sensitize one another. Although stimulants are known to cross-sensitize locomotor effects, the evidence for cross-sensitization between stimulants and sex is less clear. OBJECTIVES: This study determined the effects of single and repeated pre-exposure to methylphenidate (MPH) or sex on one another in adult male rats. METHODS: Cross-sensitization between MPH (5 mg/kg) and sex (30 min with sexually experienced female) was examined. Adult male rats were pre-exposed to 0, 1, or 10 trials of either sex or MPH before being exposed to the other reward. Locomotor chambers were used in MPH trials. Bilevel chambers were used in sexual trials, and sexual behaviors were video scored. RESULTS: The amount of prior sexual experience differentially influenced the ceiling of MPH-dependent sensitization; in the last drug trial, locomotion was highest in males given 1 previous sexual trial compared with 0 or 10. Compared with MPH-naive males, pre-exposure to MPH (1 and 10 trials) reduced the number of ejaculations without impacting sexual performance (intromission/mount latency and frequency). CONCLUSIONS: These findings indicate that the degree of pre-exposure to a reward can differentially affect reactivity to novel rewards. The results showed that previous findings of cross-sensitization between amphetamine and sex do not extend to MPH. However, exposure to MPH prior to sexual experience can increase the amount of sexual stimulation needed to achieve ejaculation.
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Estimulantes do Sistema Nervoso Central , Metilfenidato , Ratos , Masculino , Feminino , Animais , Metilfenidato/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Anfetamina/farmacologia , CopulaçãoRESUMO
The spread of "cancel culture" related to sex and gender controversies in North America is examined as part of a larger movement to politicize sex research findings and certain sex and gender narratives as "correct" and "incorrect" from a so-called social justice standpoint. This binary is then used by academic administrators and empowered individuals or self-interest groups to reward or punish scholars for their viewpoints. The cases described by Meyer-Bahlburg, Lowrey, and Hooven are concrete examples of a growing "sexual McCarthyism" where empirical results are challenged by offended social justice "warriors" and embellished on social media into ad hominem attacks, to the point that it can damage-or even cancel-the careers of productive sexual scientists. This occurs largely out of fear on the part of academic administrators and lawyers charged with protecting the university from "brand damage" that might occur if the offending scholar is not dealt with. Sexual scientists are being vilified for research on sex differences, sex/gender assignment and subsequent causes for transitioning and/or de-transitioning, research that shows few or no untoward social or psychological effects of viewing pornography, research that debunks the notion of porn or sex "addiction," research showing the efficacy of medications to treat sexual desire disorders in women, research on "minor attracted persons" and even animal research that dares to show homologies to human sexual behavior. The silencing of empirical evidence and alternative viewpoints is contrary to the intellectual mission of universities and destructive to academic and political freedoms.
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Neoplasias , Comportamento Sexual , Humanos , Feminino , Masculino , Sexualidade , América do NorteRESUMO
Reward based learning is broadly acknowledged to underpin the development and maintenance of addictive behaviour although the mechanism in sexual compulsivity is less understood. Using a Pavlovian-to-Instrumental Transfer (PIT) task we tested whether the motivational aspect of conditioned Pavlovian conditioned stimulus invigorated instrumental responding in relation to specific compatible monetary rewards. Performance on the task was analysed between two groups of males based on Low (N = 38) and High (N = 41) self-report online sexual behaviour (OSB). Psychometric tests including sexual compulsivity scale and behavioural activation/behavioural inhibition (BIS/BAS) were also administered to determine the relationship between OSB and general reward sensitivity. We show clear evidence of acquisition in the Pavlovian and instrumental conditioning phases. Specific transfer effect was greater in the High-OSB group although the difference compared to the Low-OSB group was non-significant. OSB negatively correlated with both BIS and BAS indicative of introversion and low reward sensitivity. OSB positively correlated with sexual compulsivity although it is unclear whether individuals in the High-OSB group considered their behaviour either excessive or problematic. These findings contribute to the ongoing debate regarding the nature of problematic OSB. Fundamental differences in motivational characteristics and mechanism contributing to compulsive behaviour in relation to high-OSB might indicate incompatibility with behavioural addiction models. PIT was not enhanced in high-OSB by appetitive conditioning, although problematic OSB could stem from failure to inhibit actions. Further research should investigate whether aversive conditioning differentially affects responding in high-OSB individuals, potentially explaining perseverant behaviour despite negative consequences.
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Comportamento Aditivo , Transferência de Experiência , Condicionamento Clássico/fisiologia , Condicionamento Operante/fisiologia , Humanos , Masculino , Recompensa , Comportamento Sexual , Transferência de Experiência/fisiologiaRESUMO
Intracerebroventricular (ICV) administration of estradiol benzoate (E2B) and progesterone (P) induces intense lordosis behavior in ovariectomized rats primed peripherally with E2B. The present study tested the hypothesis that the Kisspeptin (Kiss) and melanin-concentrating hormone (MCH) pathways regulate female sexual behavior induced by these steroid hormones. In Experiment 1, we tested the relevance of the Kiss pathway by ICV infusion of its inhibitor, kiss-234, before administration of E2B or P in estrogen-primed rats. Lordosis induced by E2B alone or with the addition of P was reduced significantly at 30, 120, and 240 min. In Experiment 2, ICV infusion of MCH 30 min before E2B or P significantly reduced lordosis in rats primed with E2B alone. These data support the hypothesis that the Kiss and MCH pathways, which can release or modulate gonadotropin-releasing hormone (GnRH), are involved in E2B- and P-induced lordosis.
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Lordose , Progesterona , Animais , Feminino , Ratos , Estradiol/farmacologia , Hormônio Liberador de Gonadotropina/farmacologia , Kisspeptinas/farmacologia , Lordose/induzido quimicamente , Ovariectomia , Progesterona/farmacologia , Comportamento Sexual Animal/fisiologiaRESUMO
Oxytocin (OT) and vasopressin (VP) are considered to be principal neurochemical substrates of bonding in monogamous species. We have reported previously that conditioning of a sexual partner preference in male rats resulted in conditioned activation of OT and VP neurons in hypothalamic paraventricular and supraoptc nuclei. Here we asked whether such conditioning would also alter OT or VP receptor densities. Sexually naïve male rats were assigned to one of three groups (n = 15/group). The Paired group received 9 copulatory training trials with sexually receptive females scented with a neutral almond odor. The Unpaired group received 9 copulatory training trials with unscented sexually receptive females. The Naïve group were not given sexual experience. Paired and Unpaired males were given a final test in an open field with two receptive females, one scented and the other unscented, to assess the development of conditioned ejaculatory preference (CEP), which was expressed significantly in the Paired group. Brains from rats in the three groups were then assessed for OT receptor (OTR) or VP1a receptor (VPR) densities within cortical, limbic and hypothalamic structures using autoradiography with selective 125I-labeled receptor ligands. Sexual experience alone increased OTR significantly in the medial preoptic area (mPOA), ventromedial hypothalamus (VMH), and central nucleus of the amygdala (CeA) in both Paired- and Unpaired-trained males compared to sexually Naïve males. No differences were found for experience on VPR densities in any region. These data add to a growing body of evidence that sexual experience alters brain function and processing of sex-related cues, and suggest that enhanced activation of OTRs in the mPOA, VMH, and CeA by conditioned OT release in those regions may underlie CEP in the male rat.
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Although mechanisms of mate preference are thought to be relatively hard-wired, experience with appetitive and consummatory sexual reward has been shown to condition preferences for partner related cues and even objects that predict sexual reward. Here, we reviewed evidence from laboratory species and humans on sexually conditioned place, partner, and ejaculatory preferences in males and females, as well as the neurochemical, molecular, and epigenetic mechanisms putatively responsible. From a comprehensive review of the available data, we concluded that opioid transmission at µ opioid receptors forms the basis of sexual pleasure and reward, which then sensitizes dopamine, oxytocin, and vasopressin systems responsible for attention, arousal, and bonding, leading to cortical activation that creates awareness of attraction and desire. First experiences with sexual reward states follow a pattern of sexual imprinting, during which partner- and/or object-related cues become crystallized by conditioning into idiosyncratic "types" that are found sexually attractive and arousing. These mechanisms tie reward and reproduction together, blending proximate and ultimate causality in the maintenance of variability within a species.
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Analgésicos Opioides , Comportamento Sexual Animal , Animais , Ejaculação/fisiologia , Feminino , Humanos , Masculino , Recompensa , Comportamento Sexual , Comportamento Sexual Animal/fisiologiaRESUMO
Understanding the foundations of the neurobiology of behavior and well-being can help us better achieve animal welfare. Behavior is the expression of several physiological, endocrine, motor and emotional responses that are coordinated by the central nervous system from the processing of internal and external stimuli. In mammals, seven basic emotional systems have been described that when activated by the right stimuli evoke positive or negative innate responses that evolved to facilitate biological fitness. This review describes the process of how those neurobiological systems can directly influence animal welfare. We also describe examples of the interaction between primary (innate) and secondary (learned) processes that influence behavior.