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Aspectos endócrinos e funcionais da expressão do hormônio concentrador de melanina (MCH) durante a lactação; Endocrine and functional aspects of melanin-concentrating hormone (MCH) expression during lactation

Alvisi, Renato Duarte
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/08/2013 PT
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28.09%
O Hormônio Concentrador de Melanina (MCH) está associado ao controle da ingestão de alimentos, peso corporal e homeostase da energia. Além disso, a lactação é um modelo fisiológico importante para estudar a integração do hipotálamo com os sinais sensoriais periféricos, como a sucção e também aqueles relacionados ao balanço energético. Concentrações mais elevadas de mRNA de MCH têm sido encontrados durante a lactação na área preóptica medial (MPOA) e na parte anterior do núcleo paraventricular do hipotálamo, especialmente em torno do 19º dia de lactação, quando este hormônio revela o seu pico mais alto de expressão do mRNA. O significado fisiológico desse fenômeno não é muito bem compreendido. Neste sentido, o objetivo do presente estudo foi contribuir para a investigação dos fatores que influenciam os sistemas endócrinos e sensoriais na expressão da MCH e a sua relação com alterações neuroendócrinas e comportamentais que envolvem o final da lactação, o desmame e a perpetuação do ciclo reprodutivo. Ratas Wistar (n = 56), foram divididas em subgrupos de quatro animais, as quais foram sacrificadas do 15º ao 21º dia de lactação, com (CS) ou sem (SS) sucção. O MCH e a proteína Fos foram avaliados na área hipotalâmica lateral (LHA)...

Criação de objectos de aprendizagem de acordo com o modelo múltiplas perspectivas para estruturar objectos de aprendizagem

Marques, Célio Gonçalo; Carvalho, Ana Amélia Amorim
Fonte: Ediciones Universidad Salamanca Publicador: Ediciones Universidad Salamanca
Tipo: Artigo de Revista Científica
Publicado em //2008 POR
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27.22%
A Internet está a contribuir para uma grande mudança no modo como os materiais educacionais são concebidos, desenvolvidos e distribuídos. Estamos a referir-nos aos objectos de aprendizagem, a serem usados em unidades curriculares leccionadas em regime de b-Learning e presencial com recurso aos LMSs. Nesta comunicação começamos por descrever o conceito de objecto de aprendizagem, referimos algumas das principais iniciativas de normalização e enumeramos várias ferramentas de autoria. Como resposta a algumas das preocupações actuais neste campo, apresentamos o modelo Múltiplas Perspectivas para Estruturar Objectos de Aprendizagem (MPOA) e com base nele descrevemos a criação de objectos de aprendizagem para utilizar em unidades curriculares de diversas licenciaturas da Escola Superior de Gestão do Instituto Politécnico de Tomar. Por fim, enunciamos um conjunto de problemas, dificuldades e limitações associado às ferramentas utilizadas na criação dos referidos objectos.

The effects of nitric oxide-cGMP pathway stimulation on dopamine in the medial preoptic area and copulation in DHT-treated castrated male rats

Sato, Satoru M.; Wersinger, Scott R.; Hull, Elaine M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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18.17%
Dopamine (DA) in the medial preoptic area (MPOA) provides important facilitative influence on male rat copulation. We have shown that the nitric oxide-cGMP (NO-cGMP) pathway modulates MPOA DA levels and copulation. We have also shown that systemic estradiol (E2) maintains neuronal NO synthase (nNOS) immunoreactivity in the MPOA of castrates, as well as relatively normal DA levels. This effect of E2 on nNOS probably accounts for at least some of the previously demonstrated behavioral facilitation by intra-MPOA E2 administration in castrates. Therefore, we hypothesized that stimulation of the MPOA NO-cGMP pathway in dihydrotestosterone (DHT)-treated castrates should restore DA levels and copulatory behaviors. Reverse-dialysis of a NO donor, sodium nitroprusside (SNP), increased extracellular DA in the MPOA of DHT-treated castrates and restored the ability to copulate to ejaculation in half of the animals. A cGMP analog, 8-Br-cGMP, also increased extracellular DA, though not as robustly, but did not restore copulatory ability. The effectiveness of the NO donor in restoring copulation and MPOA DA levels is consistent with our hypothesis. However, the lack of behavioral effects of 8-Br-cGMP, despite its increase in MPOA DA, suggests that NO may have additional mediators in the MPOA in the regulation of copulation. Furthermore...

Inactivation of the Periaqueductal Gray Attenuates Antinociception Elicited by Stimulation of the Rat Medial Preoptic Area

Zhang, Yi-Hong; Ennis, Matthew
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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18.14%
The medial preoptic area (MPOA) is a sexually dimorphic structure that plays key roles in gonado-steroidal regulation and thermoregulation. The MPOA may be involved in sex-based differences in nociceptive processing and steroid hormones effect on pain thresholds. Consistent with this, there is evidence that MPOA can produce antinociception or hyperalgesia. MPOA stimulation inhibits spinal cord or trigeminal neuronal responses to noxious stimuli or produces analgesia, yet most of these studies utilized electrical stimulation which antidromically activates periaqueductal gray (PAG) and rostroventromedial medulla (RVM) neurons involved in descending modulation of nociception. Effects of selective activation of MPOA neurons on behavioral indices of antinociception and the site-specificity of such responses are unknown. To address these questions, we examined the influence of MPOA microinjections of d, l homocysteate (DLH) on hindlimb and tail nocifensive reflexes in lightly anesthetized rats. DLH, but not saline, microinjections into several MPOA subregions markedly increased withdrawal response latencies to noxious thermal stimuli. Antinociceptive effects of MPOA activation were abolished by microinjection of lidocaine into PAG. These results suggest that activation of MPOA neurons produces antinociception that is at least partly mediated by projections to PAG.

Cell Proliferation and Survival in the Mating Circuit of Adult Male Hamsters: Effects of Testosterone and Sexual Behavior

Antzoulatos, Eleni; Magorien, Julie E.; Wood, Ruth I.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
18.09%
The transient actions of gonadal steroids on the adult brain facilitate social behaviors, including reproduction. In male rodents, testosterone acts in the posterior medial amygdala (MeP) and medial preoptic area (MPOA) to promote mating. Adult neurogenesis occurs in both regions. The current study determined if testosterone and/or sexual behavior promote cell proliferation and survival in MeP and MPOA. Two experiments were conducted using the thymidine analog BrdU. First, gonad-intact and castrated male hamsters (n=6/group) were compared 24 hours or 7 weeks after BrdU. In MeP, testosterone stimulated cell proliferation 24 hours after BrdU (intact: 22.8±3.9 cells/mm2, castrate: 13.2±1.4cells/mm2). Testosterone did not promote cell proliferation in MPOA. Seven weeks after BrdU, cell survival was sparse in both regions (MeP: 2.5±0.6 and MPOA: 1.7±0.2 cells/mm2), and was not enhanced by testosterone. In Experiment 2, gonad-intact sexually-experienced animals were mated weekly to determine if regular neural activation enhances cell survival 7 weeks after BrdU in MeP and MPOA. Weekly mating failed to increase cell survival in MeP (8.1±1.6 vs. 9.9±3.2 cells/mm2) or MPOA (3.9±0.7 vs. 3.4±0.3 cells/mm2). Furthermore, mating at the time of BrdU injection did not stimulate cell proliferation in MeP (8.9±1.7 vs. 8.1±1.6 cells/mm2) or MPOA (3.6±0.5 vs. 3.9±0.7 cells/mm2). Taken together...

CIRCULATING PROLACTIN, MPOA PROLACTIN RECEPTOR EXPRESSION AND MATERNAL AGGRESSION IN LACTATING RATS

Consiglio, Angelica R.; Bridges, Robert S.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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27.22%
Maternal aggression is most intense in lactating rats from the 3rd to the 12th day postpartum. The purpose of this study was to determine if plasma prolactin (PRL) and prolactin receptor (PRL-RL) mRNA expression in the medial preoptic area (MPOA) of lactating rats are altered in association with maternal aggression. Lactating Sprague Dawley rats were divided into 5 groups and exposed for 10 minutes to an intruder male or to an object on postpartum day 8. Trunk blood and the brain of the dams were collected 30 or 240 minutes after exposure and from a non-exposed group. Lower levels of prolactin were found 30 minutes after the aggression test. No change was detected in the number of cells expressing PRL-RL mRNA by in situ hybridization histochemistry (ISHH) as a function of testing. However, the correlation between plasma PRL and PRL-RL mRNA expression in the mothers changed from positive in control females to negative in intruder exposed animals. These data support the concept that a maternal aggressive experience, while acutely altering PRL secretion, fails to affect PRL-RL mRNA expression.

The changing role of the medial preoptic area in the regulation of maternal behavior across the postpartum period: facilitation followed by inhibition

Pereira, Mariana; Morrell, Joan I.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.96%
Maternal behavior in rats undergoes considerable plasticity in parallel to the developmental stage of the pups, resulting in distinct patterns of maternal behavior and care at different postpartum time points. The medial preoptic area (mPOA) of the hypothalamus is one critical neural substrate underlying the onset and early expression of maternal behavior in rats but little is known about its specific functional role in the evolving expression of maternal behavior across the postpartum period. The present study uses a reversible local neural inactivation method to examine the role of the mPOA in the regulation of maternal behavior throughout the postpartum period, particularly extending into the late postpartum, a little examined period. This approach avoids the compensatory plasticity in CNS that occurs after permanent lesions, and allows the repeated testing of same individuals. Early (PPD7-8) and late (PPD 13-14) postpartum maternal behavior was evaluated in female rats following infusions of bupivacaine or vehicle into the mPOA or into control areas. As expected, mPOA inactivation severely but transiently disrupted early postpartum maternal behavior whereas infusion of vehicle or inactivation of adjacent control sites did not. Later in the postpartum period...

The medial preoptic area is necessary for motivated choice of pup- over cocaine-associated environments by early postpartum rats

Pereira, Mariana; Morrell, Joan I.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
18.2%
Converging evidence suggests that the motivation to seek cocaine during the postpartum period is significantly impacted by the competing incentives of offspring, a stimulus unique to this life stage. In the present study, the functional role of the medial preoptic area (mPOA), a critical site involved in maternal responsiveness, on processing incentive value of pup-associated cues and influencing response allocation for pup- over cocaine-associated environments was investigated using a concurrent pup/cocaine choice conditioned place preference (CPP) paradigm. Early postpartum females with bilateral guide cannulae aimed into the mPOA or into anatomical control sites were conditioned, from postpartum days (PPD) 4 to 7, to associate different uniquely featured environments with pups or cocaine. CPP was tested on PPD8 following intra-mPOA infusions of either 2% bupivacaine or saline vehicle. In two additional experiments, the effects of intra-mPOA infusions of bupivacaine on expression of conditioned responding induced by environments associated with either pups or cocaine were examined separately. Transient inactivation of the mPOA selectively blocked the conditioned preferences for pup-associated environments, significantly contrasting the robust pup-CPP found in non-surgical and intra-mPOA vehicle-treated females. In contrast...

Dopaminergic projections to the medial preoptic area of postpartum rats

Miller, Stephanie M.; Lonstein, Joseph S.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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18.09%
Dopamine receptor activity in the rodent medial preoptic area (mPOA) is crucial for the display of maternal behaviors, as well as numerous other physiological and behavioral functions. However, the origin of dopaminergic input to the mPOA has not been identified through neuroanatomical tracing. To accomplish this, the retrograde tracer Fluorogold was iontophoretically applied to the mPOA of postpartum laboratory rats, and dual-label immunocytochemistry for Fluorogold and tyrosine hydroxylase later performed to identify dopaminergic cells of the forebrain and midbrain projecting to the mPOA. Results indicate that the number of dopaminergic cells projecting to the mPOA is moderate (~90 cells to one hemisphere), and that these cells have an unexpectedly wide distribution. Even so, more than half of the dual-labeled cells were found in what has been considered extensions of the A10 dopamine group (particularly the ventrocaudal posterior hypothalamus and adjacent medial supramammillary nucleus), or in the A10 cells of the ventral tegmental area. The rostral hypothalamus and surrounding region also contained numerous dual-labeled cells, with the greatest number found within the mPOA itself (including in the AVPV and PVpo). Notably, dual-labeled cells were rare in the zona incerta (A13)...

The role of the medial preoptic area in appetitive and consummatory reproductive behaviors depends on sexual experience and odor volatility in male Syrian hamsters

Been, Laura E.; Petrulis, Aras
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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18.25%
In Syrian hamsters (Mesocricetus Auratus), the expression of reproductive behavior requires the perception and discrimination of sexual odors. The behavioral response to these odors is mediated by a network of ventral forebrain nuclei, including the medial preoptic area (MPOA). The role of MPOA in male copulatory behavior has been well-studied, but less is known about the role of MPOA in appetitive aspects of male reproductive behavior. Furthermore, many previous studies that examined the role of MPOA in reproductive behavior have used large lesions that damaged other nuclei near MPOA or fibers of passage within MPOA, making it difficult to attribute post-lesion deficits in reproductive behavior to MPOA specifically. Thus, the current study used discrete, excitotoxic lesions of MPOA to test the role of this nucleus in opposite-sex odor preference and copulatory behavior in both sexually-naïve and sexually-experienced males. Lesions of MPOA eliminated preference for volatile, opposite-sex odors in sexually-naïve, but not sexually-experienced, males. When, however, males were allowed to contact the sexual odors, preference for female odors remained intact. Surprisingly, lesions of MPOA caused severe copulatory deficits only in sexually-naïve males...

Blocking oxytocin receptors inhibits vaginal marking to male odors in female Syrian hamsters

Martinez, Luis A.; Albers, H. Elliott; Petrulis, Aras
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.96%
In Syrian hamsters (Mesocricetus auratus), precopulatory behaviors such as vaginal scent marking are essential for attracting a suitable mate. Vaginal marking is dependent on forebrain areas implicated in the neural regulation of reproductive behaviors in rodents, including the medial preoptic/anterior hypothalamus (MPOA-AH). Within MPOA-AH, the neuropeptide oxytocin (OT) acts to facilitate copulation (lordosis), as well as ultrasonic vocalizations towards males. It is not known, however, if OT in this area also facilitates vaginal marking. In the present study, a specific oxytocin receptor antagonist (OTA) was injected into MPOA-AH of intact female Syrian hamsters to determine if oxytocin receptor-dependent signaling is critical for the normal expression of vaginal marking elicited by male, female, and clean odors. OTA injections significantly inhibited vaginal marking in response to male odors compared to vehicle injections. There was no effect of OTA on marking in response to either female or clean odors. When injected into the bed nucleus of the stria terminalis (BNST), a nearby region to MPOA-AH, OTA was equally effective in decreasing marking. Finally, the effects of OTA appear to be specific to vaginal marking, as OTA injections in MPOA-AH or BNST did not alter general locomotor activity...

Leptin Receptor Expressing Neurons in the Dorsomedial Hypothalamus and Median Preoptic Area Regulate Sympathetic Brown Adipose Tissue Circuits

Zhang, Yan; Kerman, Ilan A.; Laque, Amanda; Nguyen, Phillip; Faouzi, Miro; Louis, Gwendolyn W.; Jones, Justin C.; Rhodes, Chris; Münzberg, Heike
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 02/02/2011 EN
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17.96%
Brown adipose tissue (BAT) thermogenesis is critical to maintain homoeothermia and is centrally controlled via sympathetic outputs. Body temperature and BAT activity also impact energy expenditure and obesity is commonly associated with decreased BAT capacity and sympathetic tone. Severely obese mice that lack leptin or its receptor (LepRb) show decreased BAT capacity, sympathetic tone and body temperature, and thus are unable to adapt to acute cold exposure (Trayhurn et al., 1976). LepRb expressing neurons are found in several hypothalamic sites including the dorsomedial hypothalamus (DMH) and median preoptic area (mPOA), both critical sites to regulate sympathetic, thermoregulatory BAT circuits. Specifically, a subpopulation in the DMH/dorsal hypothalamic area (DMH/DHA) is stimulated by fever inducing endotoxins or cold exposure (Dimicco and Zaretsky, 2007;Morrison et al., 2008). Using the retrograde, transsynaptic tracer pseudorabies virus (PRV) injected into the BAT of mice we identified PRV labeled LepRb neurons in the DMH/DHA and mPOA (and other sites), thus indicating their involvement in the regulation of sympathetic BAT circuits. Indeed, acute cold exposure induced cFos (as a surrogate for neuronal activity) in DMH/DHA LepRb neurons...

AN NMDA ANTAGONIST IN THE MPOA IMPAIRS COPULATION AND STIMULUS SENSITIZATION IN MALE RATS

Vigdorchik, Anna V.; Parrish, Bradley P.; Lagoda, Gwen A.; McHenry, Jenna A.; Hull, Elaine M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/2012 EN
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28.03%
Systemic injections of an NMDA antagonist have been shown to impair mating in male rats. One site where glutamate and its NMDA receptors may contribute to mating is the medial preoptic area (MPOA), which is vital for male sexual behavior. Glutamate is released in the MPOA during copulation, and especially at the time of ejaculation. We report here that the NMDA antagonist MK-801, microinjected into the MPOA, impaired copulatory behavior in sexually naïve as well as experienced males. In animals tested both as naïve and after sexual experience, drug treatment produced more profound impairment in naïve males. In addition, MK-801, microinjected into the MPOA before each of 7 noncopulatory exposures to receptive female rats, resulted in copulatory impairments on a drug-free test on day 8, relative to aCSF-treated animals; their behavior was similar to that of males that had not been pre-exposed to females. Therefore, NMDA receptors in the MPOA contribute to the control of copulation and stimulus sensitization. Glutamate, acting via NMDA receptors, regulates many neural functions, including neuronal plasticity. This is the first demonstration that a similar mechanism in the MPOA sensitizes male rats to the stimuli from a receptive female...

The Effect of Chronic Antipsychotic Drug on Hypothalamic Expression of Neural Nitric Oxide Synthase and Dopamine D2 Receptor in the Male Rat

Zhang, Xiang Rong; Wang, Ying Xin; Zhang, Zhi Jun; Li, Lei; Reynolds, Gavin P.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 13/04/2012 EN
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17.96%
Antipsychotic-induced sexual dysfunction is a common and serious clinical side effect. It has been demonstrated that both neuronal nitric oxide (nNOS) and dopamine D2 receptor (DRD2) in the medial preoptic area (MPOA) and the paraventricular nucleus (PVN) of the hypothalamus have important roles in the regulation of sexual behaviour. We investigated the influences of 21 days’ antipsychotic drug administration on expression of nNOS and DRD2 in the rat hypothalamus. Haloperidol (0.5 mg/kg/day i.p.) significantly decreased nNOS integrated optical density in a sub-nucleus of the MPOA, medial preoptic nucleus (MPN), and decreased the nNOS integrated optical density and cell density in another sub-nucleus of the MPOA, anterodorsal preoptic nucleus (ADP). Risperidone (0.25 mg/kg) inhibited the nNOS integrated optical density in the ADP. nNOS mRNA and protein in the MPOA but not the PVN was also significantly decreased by haloperidol. Haloperidol and risperidone increased DRD2 mRNA and protein expression in both the MPOA and the PVN. Quetiapine (20 mg/kg/day i.p.) did not influence the expression of nNOS and DRD2 in either the MPOA or the PVN. These findings indicate that hypothalamic nNOS and DRD2 are affected to different extents by chronic administration of risperidone and haloperidol...

Dopamine D1 Receptor Signaling in the Medial Preoptic Area Facilitates Experience-induced Enhancement of Mating Behavior in Male Rats

McHenry, Jenna A.; Bell, Genevieve A.; Parrish, Bradley P.; Hull, Elaine M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
18.03%
The medial preoptic area (MPOA) is an integral site for male sexual behavior. Dopamine is released in the MPOA before and during copulation and facilitates male rat sexual behavior. Repeated sexual experience and noncopulatory exposures to an estrous female facilitate subsequent copulation. However, the neurobiological mechanisms that mediate such enhancement remain unclear. Here, we examined the role of dopamine D1 receptors in the MPOA in experience-induced enhancement of male sexual behavior in rats. In Experiment 1, microinjections of the D1 antagonist SCH-23390 into the MPOA before each of 7 daily 30-min noncopulatory exposures to a receptive female impaired copulation on a drug-free test on day 8, compared to vehicle-treated female-exposed animals. Copulatory performance in drug-treated animals was similar to vehicle-treated males that had not been pre-exposed to females. This effect was site specific. There were no group differences in locomotor activity in an open field on the copulation test day. In Experiment 2, a separate cohort of animals was used to examine phosphorylation of dopamine-and cAMP-regulated phosphoprotein (DARPP-32) in the MPOA of animals with acute and/or chronic sexual experience. DARPP-32 is a downstream marker of D1 receptor signaling and substrate of cAMP-dependent protein kinase (PKA). Western immunoblot analysis revealed that p-DARPP-32 expression was greatest in the MPOA of males that received both acute and chronic sexual experience...

Estrous cycle variations in GABAA receptor phosphorylation enable rapid modulation by anabolic androgenic steroids in the medial preoptic area

Oberlander, JG; Porter, DM; Onakomaiya, MM; Penatti, CAA; Vithlani, M; Moss, SJ; Clark, AS; Henderson, LP
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.96%
Anabolic androgenic steroids (AAS), synthetic testosterone derivatives that are used for ergogenic purposes, alter neurotransmission and behaviors mediated by GABAA receptors. Some of these effects may reflect direct and rapid action of these synthetic steroids at the receptor. The ability of other natural allosteric steroid modulators to alter GABAA receptor-mediated currents is dependent upon the phosphorylation state of the receptor complex. Here we show that phosphorylation of the GABAA receptor complex immunoprecipitated by β2/β3 subunit-specific antibodies from the medial preoptic area (mPOA) of the mouse varies across the estrous cycle; with levels being significantly lower in estrus. Acute exposure to the AAS, 17α-testosterone (17α-MeT), had no effect on the amplitude or kinetics of inhibitory postsynaptic currents in the mPOA of estrous mice when phosphorylation was low, but increased the amplitude of these currents from mice in diestrus, when it was high. Inclusion of the protein kinase C (PKC) inhibitor, calphostin, in the recording pipette eliminated the ability of 17α-MeT to enhance currents from diestrous animals, suggesting that PKC-receptor phosphorylation is critical for the allosteric modulation elicited by AAS during this phase. In addition...

The medial preoptic area is necessary for sexual odor preference, but not sexual solicitation, in female Syrian hamsters

Martinez, Luis A.; Petrulis, Aras
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
18.17%
Precopulatory behaviors that are preferentially directed towards opposite-sex conspecifics are critical for successful reproduction, particularly in species wherein the sexes live in isolation, such as Syrian hamsters (Mesocricetus auratus). In females, these behaviors include sexual odor preference and vaginal scent marking. The neural regulation of precopulatory behaviors is thought to involve a network of forebrain areas that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). Although MA and BNST are necessary for sexual odor preference and preferential vaginal marking to male odors, respectively, the role of MPOA in odor-guided female precopulatory behaviors is not well understood. To address this issue, female Syrian hamsters with bilateral, excitotoxic lesions of MPOA (MPOA-X) or sham lesions (SHAM) were tested for sexual odor investigation, scent marking, and lordosis. MPOA-X females did not investigate male odors more than female odors in an odor preference test, indicating that MPOA may be necessary for normal sexual odor preference in female hamsters. This loss of preference cannot be attributed to a sensory deficit, since MPOA-X females successfully discriminated male odors from female odors during an odor discrimination test. Surprisingly...

SEXUAL EXPERIENCE INCREASES OXYTOCIN RECEPTOR GENE EXPRESSION AND PROTEIN IN THE MEDIAL PREOPTIC AREA OF THE MALE RAT

Gil, Mario; Bhatt, Renu; Picotte, Katie G.; Hull, Elaine M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
18.03%
Oxytocin (OT) promotes social and reproductive behaviors in mammals, and OT deficits may be linked to disordered social behaviors like autism and severe anxiety. Male rat sexual behavior is an excellent model for OT regulation of behavior, as its pattern and neural substrates are well characterized. We previously reported that OT microinjected into the medial preoptic area (MPOA), a major integrative site for male sexual behavior, facilitates copulation in sexually experienced male rats, whereas intra-MPOA injection of an OT antagonist (OTA) inhibits copulation. In the present studies, copulation on the day of sacrifice stimulated OTR mRNA expression in the MPOA, irrespective of previous sexual experience, with the highest levels observed in first-time copulators. In addition, sexually experienced males had higher levels of OTR protein in the MPOA than sexually naïve males and first-time copulators. Finally, intra-MPOA injection of OT facilitated mating in sexually naive males. Others have reported a positive correlation between OT mRNA levels and male sexual behavior. Our studies show that OT in the MPOA facilitates mating in both sexually naive and experienced males, some of the behavioral effects of OT are mediated by the OTR, and sexual experience is associated with increased OTR expression in the MPOA. Taken together...

The medial preoptic area modulates cocaine-induced activity in female rats

Tobiansky, Daniel J.; Roma, Peter G.; Hattori, Tomoko; Will, Ryan G.; Nutsch, Victoria L.; Dominguez, Juan M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/2013 EN
Relevância na Pesquisa
18.03%
Drugs of abuse exert their effects by exploiting natural neurobiological reward mechanisms, especially the mesolimbic dopamine (DA) system. However, the mesolimbic system does not operate in isolation, and input from other reward-relevant structures may play a role in cocaine’s rewarding effects. The medial preoptic area (mPOA) of the hypothalamus is involved in the regulation of two essential and naturally rewarding behaviors, sexual and maternal behaviors. It also makes strong neuroanatomical connections with areas of the mesolimbic system, particularly the ventral tegmental area (VTA). As such, the mPOA is a logical candidate for a neuroanatomical locus modulating activity in the mesolimbic system and emergent behavioral expressions of drug reward, yet the role of this structure is largely unexplored. Here, using a female rat model, we show that the mPOA innervates the VTA in a region-specific manner, lesions of the mPOA augment cocaine-induced Fos expression in the nucleus accumbens and cocaine-induced conditioned place preference. We also show that approximately 68% of mPOA-VTA efferents release γ-aminobutyric acid (GABA), over 75% are sensitive to DA as evidenced by co-localization with DA receptors, and nearly 60% of these contain both DA receptors and GABA...

Inverted-U shaped effects of D1 dopamine receptor stimulation in the medial preoptic nucleus on sexually-motivated song in male European starlings

Riters, Lauren V.; Pawlisch, Benjamin A.; Kelm-Nelson, Cynthia A.; Stevenson, Sharon A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
18.14%
Past studies in songbirds highlight a central role for the medial preoptic nucleus (mPOA) in context-appropriate vocal communication. During the breeding season, male songbirds sing primarily to attract females (sexually-motivated song) and to repel competitors (agonistically-motivated song). Past data link dopamine and D1 dopamine receptors in the mPOA to sexually-motivated but not agonistically-motivated song; however, direct effects of dopamine receptor manipulations in the mPOA on song have not been experimentally tested. Here we tested the hypothesis that D1 receptor stimulation in the mPOA selectively influences sexually-motivated male song and the possibility that the effects of D1 agonism differ at low and high doses. In a first study, breeding condition male European starlings received infusions of saline or a single dose of the D1 receptor agonist SKF 38393 on separate test days into mPOA or hypothalamic control areas. Stimulation of D1 receptors in mPOA triggered sexually-motivated but not agonistically-motivated song. A second study showed inverted-U shaped dose-response effects of the agonist such that low levels of sexually-motivated song were observed at low and high levels of D1 receptor activation. A third study showed that effects of the D1 agonist were blocked by the D1 receptor antagonist SCH 23390. These findings suggest that an optimal level of D1 dopamine receptor stimulation in mPOA is needed to facilitate sexually-motivated vocal production. The results support a central...