RESUMO
Obsessive-compulsive disorder (OCD) is a mental affliction characterized by compulsive behaviors often manifested in intrusive thoughts and repetitive actions. The quinpirole model has been used with rats to replicate compulsive behaviors and study the neurophysiological processes associated with this pathology. Several changes in the dendritic spines of the medial prefrontal cortex (mPFC) and dorsolateral striatum (DLS) have been related to the occurrence of compulsive behaviors. Dendritic spines regulate excitatory synaptic contacts, and their morphology is associated with various brain pathologies. The present study was designed to correlate the occurrence of compulsive behaviors (generated by administering the drug quinpirole) with the morphology of the different types of dendritic spines in the mPFC and DLS. A total of 18 male rats were used. Half were assigned to the experimental group, the other half to the control group. The former received injections of quinpirole, while the latter rats were injected with physiological saline solution, for 10 days in both cases. After the experimental treatment, the quinpirole rats exhibited all the parameters indicative of compulsive behavior and a significant correlation with the density of stubby and wide neckless spines in both the mPFC and DLS. Dendritic spines from both mPFC and DLS neurons showed plastic changes correlatively with the expression of compulsive behavior induced by quinpirole. Further studies are suggested to evaluate the involvement of glutamatergic neurotransmission in the neurobiology of OCD.
Assuntos
Comportamento Compulsivo , Corpo Estriado , Espinhas Dendríticas , Plasticidade Neuronal , Córtex Pré-Frontal , Quimpirol , Animais , Masculino , Espinhas Dendríticas/patologia , Córtex Pré-Frontal/patologia , Córtex Pré-Frontal/efeitos dos fármacos , Comportamento Compulsivo/fisiopatologia , Comportamento Compulsivo/patologia , Corpo Estriado/patologia , Corpo Estriado/efeitos dos fármacos , Quimpirol/farmacologia , Ratos , Plasticidade Neuronal/fisiologia , Plasticidade Neuronal/efeitos dos fármacos , Transtorno Obsessivo-Compulsivo/patologia , Transtorno Obsessivo-Compulsivo/fisiopatologia , Modelos Animais de Doenças , Agonistas de Dopamina/farmacologia , Ratos WistarRESUMO
The ability to modulate the host immune response has allowed some parasites to establish themselves in the tissues of an immunocompetent organism. While some parasite excretion/secretion products (ESPs) were recently reported to induce differentiation of regulatory T cells (Tregs), their identity is not known. This work is aimed to identify and characterize ESPs of Taenia crassiceps cysticerci linked with Treg induction in vivo. ESPs were obtained from cultures of T. crassiceps cysticerci and inoculated in mice, measuring Treg levels by flow cytometry. Proteins in ESPs were analyzed by electrophoresis; then, ESPs were classified as either differential or conserved. Differentially included proteins were MS-sequenced and functionally characterized. Only 4 of 10 ESPs induced Tregs. Proteins with catalytic activity and those involved in immunological processes predominated, supporting the idea that these molecules could play an important role in the induction of Tregs.
Assuntos
Parasitos , Taenia , Animais , Camundongos , Cysticercus , Linfócitos T Reguladores , Citometria de Fluxo , Camundongos Endogâmicos BALB CRESUMO
Sexual experience improves copulatory performance in male rats. Copulatory performance has been associated with dendritic spines density in the medial prefrontal cortex (mPFC) and nucleus accumbens (NAcc), structures involved in the processing of sexual stimuli and the manifestation of sexual behavior. Dendritic spines modulate excitatory synaptic contacts, and their morphology is associated with the ability to learn from experience. This study was designed to determine the effect of sexual experience on the density of different types or shapes of dendritic spines in the mPFC and NAcc of male rats. A total of 16 male rats were used, half of them were sexually experienced while the other half were sexually inexperienced. After three sessions of sexual interaction to ejaculation, the sexually-experienced males presented shorter mount, intromission, and ejaculation latencies. Those rats presented a higher total dendritic density in the mPFC, and a higher numerical density of thin, mushroom, stubby, and wide spines. Sexual experience also increased the numerical density of mushroom spines in the NAcc. In both the mPFC and NAcc of the sexually experienced rats, there was a lower proportional density of thin spines and a higher proportional density of mushroom spines. Results show that the improvement in copulatory efficiency resulting from prior sexual experience in male rats is associated with changes in the proportional density of thin and mushroom dendritic spines in the mPFC and NAcc. This could represent the consolidation of afferent synaptic information in these brain regions, derived from the stimulus-sexual reward association.
Assuntos
Agaricales , Núcleo Accumbens , Ratos , Masculino , Animais , Comportamento Sexual Animal , Copulação , Córtex Pré-Frontal , Espinhas DendríticasRESUMO
The heuristic approach to decision-making holds that the selection process becomes more efficient when part of the information available is ignored. One element involved in selecting information is emotional valence. If emotional congruency is related to simplified decision-making strategies, then the interaction of this factor with task complexity should exist. The present study explored how factors of this nature influence decision-making efficiency. We hypothesized that emotional congruency would have a positive effect on task execution and that the magnitude of that effect would increase with greater task complexity because in that condition the amount of information to be processed is greater, meaning that a heuristic approach to the problem would be more efficient. We design a decision in browser decision-making task in which participants had to select emotional images to gain points. Depending on the correlation between emotional valence and in-task image value, we defined three emotional congruency conditions: direct, null, and inverse. Our results show that distinct types of emotional congruency have differential effects on behavior. While direct congruency-enhanced overall decision-making performance, inverse congruency interacted with task complexity to modify the pace at which task feedback affected behavior.
Assuntos
Tomada de Decisões , Emoções , Humanos , Expressão FacialRESUMO
According to the different stages of the estrous cycle, female rats exhibit behavioral changes associated with variations in sex hormone levels that affect the functionality of certain brain regions. In this study, we characterized the attention that female rats paid to a sexually-experienced male and the degree of electroencephalographic (EEG) activation and coupling between the medial prefrontal and posterior parietal cortices during antagonistic phases of the estrous cycle (proestrus-estrus vs. diestrous). The degree of attention paid to the stimulus was measured by the number of nose pokes performed while the rats were in a sexual incentive motivation box. EEGs were recorded in two conditions: a) awake-quiet state with no male rat present; and b) awake-quiet state in the presence of a male. Only during proestrus-estrus did the females show lower latency with a higher frequency and duration of nose pokes. In both cortices, the receptive females presented higher absolute power in all EEG bands recorded in the presence of the male, regardless of the phase of the estrous cycle. They also had greater EEG coupling between the medial prefrontal and posterior parietal cortices of the left hemisphere in all EEG bands regardless of the presence of a male. The higher synchronization between prefronto-parietal areas could be associated with the greater attention paid to, and adequate processing of, the sexual stimuli emitted by the male. Hence, it is probable that manifesting the proceptivity and receptivity behaviors characteristic of the proestrus-estrus phase requires a higher functional coupling between the prefrontal and parietal cortices.
Assuntos
Eletroencefalografia , Ciclo Estral , Masculino , Ratos , Feminino , Animais , Proestro , Ciclo Estral/fisiologia , Comportamento Sexual Animal/fisiologia , Estro/fisiologiaRESUMO
Stress induces diverse effects on sexual behavior, ranging from enhanced execution to the complete abolishment of sexual interaction. However, it is not clear whether some characteristics intrinsic to the individual that experiences stress could also explain this differential effect. This study seeks to relate sexual execution to susceptibility to stress (as post-stress sexual motivation). To this end, we designed a three-session experimental paradigm. In the first session, male rats were allowed to copulate with a female. In the second, the male rats received electric foot shocks as they attempted to approach the female. The third and final session was used to determine the effects of stress on sexual behavior by separating the rats into two groups: a motivation-impaired group (rats that did not cross to achieve copulation), and an unimpaired group (rats that did cross). Mount latency was affected immediately by stress in both groups, though only the non-crossing group presented a reduced number of copulatory events. The rats that did not cross showed slower-paced sexual execution even before stress was applied compared to the rats that crossed. These results show that rats that are more susceptible to stress present higher ejaculation latency even before the application of stress.
Assuntos
Ejaculação , Comportamento Sexual Animal , Ratos , Masculino , Feminino , Animais , Copulação , MotivaçãoRESUMO
Pentylenetetrazol (PTZ) blocks the inhibitory action of GABA, triggering a Glu-mediated hyperexcitation of the dendritic spines in hippocampal CA1 pyramidal neurons that leads to the generation of epileptiform seizures. The aim of this work was to determine the effect of PTZ on the electrical activity of the hippocampal pyramidal neurons in male rats. Bipolar electrodes were implanted stereotaxically in the right and left hippocampal CA1 fields of adults, and PTZ (65 mg/kg) was administered i.p. Simultaneous recordings of the field activity and the firing rate (multiunitary activity, MUA) were analyzed at 10, 20, and 30 min post-administration of PTZ. Only rats that presented tonic-clonic seizures during the first 1-5 min after PTZ treatment were included in the study. The recordings of the field activity were analyzed in 4 frequency bands. In both the right and left hippocampal CA1 fields, the relative power corresponding to the slow waves (4-7 Hz) increased, while in the bands 13-30 Hz and 31-50 Hz, it decreased at 10, 20, and 30 min post-PTZ. MUA recordings were analyzed at four levels. The highest levels corresponded to larger amplitudes of the action potentials in the pyramidal neurons. The firing rates of the PTZ-treated rats did not differ from baseline but presented a significant decrement at 10, 20, and 30 min post-PTZ. The decreased firing rate of the hippocampal CA1 pyramidal neurons after PTZ treatment could be associated with plastic changes of dendritic spines along with some microenvironmental adaptations at synaptic level, after neuronal PTZ-mediated hyperexcitation.
Assuntos
Pentilenotetrazol , Células Piramidais , Ratos , Masculino , Animais , Pentilenotetrazol/farmacologia , Convulsões/induzido quimicamente , Hipocampo , Potenciais de AçãoRESUMO
The evaluation of external and internal stimuli permits the ongoing actualization of choice-related information and, thus, the association between stimuli and outcomes. This process is essential to decision-making as it allows constant adaptation to environmental changes in order to maximize gains and minimize losses. Reversal learning paradigms are used to study this process, which has been associated with prefrontal cortex activity (frontopolar, dorsolateral) in conjunction with posterior areas (parietal, temporal), due to their participation in integrating and processing the stimuli-reward relation. The aim of this study was to assess the cortical functionality associated with reversal learning during the decision-making process. The EEG activity of 22 young men was recorded while performing a decision-making task in a reversal learning condition compared to an initial learning condition. EEG data were analyzed during evaluation of the stimuli, before motor execution (formation of preferences), and during task feedback (outcome evaluation). The formation of preferences stage was characterized by a higher correlation of the alpha2 band between the parietal cortices. In the feedback stage of the reversal learning condition, a higher absolute power of the theta band in the left dorsolateral (F3), and a lower correlation of the alpha1 band between the right frontopolar and dorsolateral (Fp2-F4), as well as between the right frontopolar and temporal (Fp2-T4), were observed. The data obtained show that the EEG activity of the areas recorded changed in the evaluation of the stimuli information in the reversal learning condition during a decision-making task.
Assuntos
Córtex Pré-Frontal , Reversão de Aprendizagem , Tomada de Decisões , Humanos , Masculino , Lobo Parietal , RecompensaRESUMO
Decision-making is a process that allows adapting behavior in response to feedback to achieve a goal. Previous studies have suggested that the cerebral cortex shows different activation patterns in response to feedback. However, the effects of reward and punishment on learning contexts and decision-making are not clear. Thus, this experiment compared the effects of reward and punishment on behavior and the electroencephalographic activity of cortical areas related to decision-making in a no-risk context. Twenty healthy males were asked to perform a decision-making task under two conditions in which the goal was to finish in the shortest time possible. In the reward condition, the more points the participant accumulated the sooner the task ended, while in the punishment condition, the more points accumulated the longer the task lasted. Lower reaction times were found in the reward condition, characterized by a higher absolute power of the slow bands in almost all the cortices recorded. Changes in the interhemispheric correlation were also obtained in the comparison of the two feedback conditions. Results suggest that changes in the type of feedback affect cortical functionality and behavioral execution during decision-making, with the reward being related to a quick emotional response strategy and punishment associated with slower and, likely, more reasoned responses.
Assuntos
Ondas Encefálicas/fisiologia , Córtex Cerebral/fisiologia , Tomada de Decisões/fisiologia , Eletroencefalografia , Retroalimentação Psicológica/fisiologia , Desempenho Psicomotor/fisiologia , Punição , Recompensa , Adolescente , Adulto , Humanos , Masculino , Adulto JovemRESUMO
Prenatal stress affects brain functionality and sexual behavior. The medial prefrontal cortex (mPFC) participates in the integration and processing of sexual stimuli. Electroencephalographic (EEG) theta activity has been associated with attention as well as rewarding and sexually motivated states. Considering that the induction of sexual motivation requires attention to, and the adequate processing of, sexual stimuli, this study aimed to evaluate the effects of exposure to stress during the prenatal period on EEG activity in the mPFC during nose pokes in adulthood, actions which are indicators of attention to a receptive female. Eighteen sexually experienced male rats were used, nine stressed prenatally by immobilization during days 14-21 of gestation (stress-exposed group). The other nine formed the control group. All rats were implanted bilaterally in the mPFC (specifically in prelimbic areas) and were allowed one intromission with a receptive female to induce a sexually motivated state before the experimental session. During this session, both nose pokes and non-contact erections in the male rats were evaluated in the presence of an inaccessible receptive female. EEGs were recorded only during nose pokes. The stress-exposed group presented lower nose poke duration, fewer non-contact erections, and lower relative power of the theta band (4-7 Hz) in both prefrontal areas. Considering that the prevalence of this band is associated with attention and motivational processes, these data confirm the deleterious effect of prenatal stress on attention and sexual activation to sexually relevant stimuli in male rats during adulthood.
Lay summariesPrenatal stress diminishes attention and activation behaviors in receptive females.Prenatal stress decreases prefrontal activation in the presence of receptive females.Prenatal stress decreases prefrontal theta rhythms in male rats.
Assuntos
Efeitos Tardios da Exposição Pré-Natal , Comportamento Sexual Animal , Animais , Eletroencefalografia , Feminino , Masculino , Motivação , Córtex Pré-Frontal , Gravidez , Ratos , Comportamento Sexual Animal/fisiologia , Estresse PsicológicoRESUMO
Decision-making is a process that allows individuals to choose an option or alternative in order to maximize a subjective gain or achieve a set goal by evaluating and establishing a preference based on contextual and internal information. Ernst and Paulus proposed a three-stage temporal division of this process: 1) the assessment and formation of preferences among possible options; 2) the selection and execution of an action; and 3) the experience or evaluation of an outcome. Each stage involves the participation of several brain regions, including the prefrontal, parietal, and temporal cortices. There are reports of distinct functionalities of these cortices for each stage of decision-making, but those studies focus on individual stages and do not provide any direct comparisons among them. Therefore, using a task that allows the clear temporal separation of the three stages of decision-making, we characterized the electroencephalographic activity (EEG) of those cortices in 30 healthy right-handed men during preference changes that occurred while performing a decision-making task. As the trials progressed, the preference for the stimulus shifted towards maximizing gains on the task. Forty trials sufficed to maintain these behavioral changes. Specific EEG patterns for each stage of decision-making were obtained, and it was possible to associate them with the cognitive processes involved in each one. These EEG data support the temporal division of the decision-making process proposed by Ernest and Paulus and show that the task designed could be a useful tool for determining behavioral and cerebral changes associated with stimuli preference during decision-making.
Assuntos
Tomada de Decisões/fisiologia , Eletroencefalografia , Adolescente , Adulto , Encéfalo/fisiologia , Humanos , Masculino , Vias Neurais/fisiologia , Lobo Parietal/fisiologia , Córtex Pré-Frontal/fisiologia , Desempenho Psicomotor/fisiologia , Lobo Temporal/fisiologia , Adulto JovemRESUMO
Abstract. Objective. This study characterized the electroencephalographic correlation (rEEG) between prefrontal and parietalcortices in young men while solving logical-mathematical problems after 18 sessions of cognitive training. Method. Two training groups were formed: one trained with gradually increased complexity (CT), the other with no increase in complexity (ST). Results. CT had a greater number of correct responses in the post-training evaluation than ST and showed a higher correlation between the left frontopolar-parietal cortices in almost all EEG bands, and between the dorsolateral-parietal cortices in the alpha1 band while solving math problems post-training. Results suggest that major functional synchronization between the left prefrontal and parietal cortices plays an important role in improving mathematical problem-solving after cognitive training.
Resumen Objetivo. El presente estudio caracteriza la correlación electroencefalográfica (rEEG) entre las cortezas prefrontal y parietal en hombres jóvenes durante la resolución de problemas lógico-matemáticos después de 18 sesiones de entrenamiento cognitivo. Método. Se formaron dos grupos de entrenamiento: uno entrenado con un incremento gradual de complejidad (CT) y el otro sin incremento de complejidad (ST). Resultados. El grupo CT presentó un mayor número de respuestas correctas que el grupo ST en la evaluación post entrenamiento, a su vez mostró un incremento en la correlación entre las cortezas frontopolar y parietal izquierdas en la mayoría de las bandas, así como entre las cortezas dorsolateral y parietal en la banda alfa1 durante la resolución de problemas posterior al entrenamiento. Los resultados sugieren que el incremento en la sincronización funcional entre las cortezas prefrontal y parietal izquierdas juega un rol importante en la resolución de problemas matemáticos después del entrenamiento cognitivo.
Assuntos
Humanos , Masculino , Adulto , Eletroencefalografia , Treino Cognitivo , Lógica , Matemática , MéxicoRESUMO
There is evidence that research on sleep among New World monkeys may provide important knowledge related to the evolution of sleep more broadly in the primate order. Digital electroencephalographic (EEG) analyses provide essential knowledge on sleep in the spider monkey. Recently, specific EEG bands related to sleep in these animals have been obtained using principal component analysis, but the exact spatio-temporal distribution of these EEG bands in this species has not yet been analyzed. This study determined the topographic distribution of the EEG spectral power of ad hoc broad bands during rapid eye movement sleep, nonrapid eye movement sleep, and wakefulness. Superficial EEG activity was obtained from the occipital, frontal, and central areas of six young adult male monkeys housed in a laboratory. During wakefulness, occipital areas showed high absolute power in the 1-3, 3-12, and 11-30 Hz ranges, while during nonrapid eye movement 1 sleep the highest absolute power was in the 13-30 Hz range. During nonrapid eye movement 3 sleep, frontal and central areas showed a high absolute power in the 18-19 Hz range. Finally, the right central area showed a high absolute power in the 20-30 Hz range during rapid eye movement sleep. This topographic distribution of EEG bands could represent the brain organization required for arousal and mnemonic processing during sleep in the spider monkey.
Assuntos
Ateles geoffroyi , Atelinae , Animais , Eletroencefalografia/veterinária , Masculino , Sono , VigíliaRESUMO
Puberty is a transitional period from juvenile stage to adulthood, followed by the functional maturation of gonads and reproductive organs. This period is sensitive to environmental pollutants like cadmium (Cd), a heavy metal that represents a serious health risk. Cd is an endocrine disruptor that interferes with reproduction by causing oxidative stress in the reproductive organs, affecting the sexual function and decreasing testosterone (T) levels. However, little research has been done on the effects of Cd on puberty markers and antioxidant systems. In this study, we evaluated the effects of Cd on puberty markers: preputial separation, testes descent and T levels, and the antioxidant activity (SOD, CAT, GSH/GSSG and TAC) in the seminal vesicles, testis and epididymis. Male Wistar pups were treated with 1â¯mg/kg Cd or saline solution by i.p. injection from day 1 to 35; the other treatment was administrated for 49 days. At the end of treatment, the animals were sacrificed, and the tissues of interest dissected, weighed and prepared for the respective assays. Cd treated rats from birth to puberty showed a delay onset in the puberty markers and a low weight in reproductive organs. Also, Cd induced differential effects on the redox system in reproductive organs and decreased T levels, these effects played a pivotal role in the delay of puberty markers onset (testes descent and preputial separation), affecting the development and sexual maturity of the male rats.
Assuntos
Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Epididimo/efeitos dos fármacos , Glândulas Seminais/efeitos dos fármacos , Maturidade Sexual/efeitos dos fármacos , Testículo/efeitos dos fármacos , Animais , Cádmio/sangue , Catalase/metabolismo , Epididimo/crescimento & desenvolvimento , Epididimo/metabolismo , Glutationa/metabolismo , Masculino , Tamanho do Órgão/efeitos dos fármacos , Oxirredução , Ratos Wistar , Glândulas Seminais/crescimento & desenvolvimento , Glândulas Seminais/metabolismo , Superóxido Dismutase/metabolismo , Testículo/crescimento & desenvolvimento , Testículo/metabolismo , Testosterona/sangueRESUMO
This study evaluated the effect of stress during puberty on sexual motivation and the correlation between serum testosterone levels (T) and the absolute power of the theta electroencephalographic rhythms, recorded in the medial prefrontal cortex (mPFC) and basolateral amygdala (BLA) of adult male rats. Thirty males of the stressed group (SG, housed 1 per cage from days 25-50) and 30 controls (CG, housed 5 per cage), were tested in copulatory interactions at 90 days of age. The above mentioned physiological parameters were obtained during the awake-quiet state in a sub-group without sexual motivation (WSM, n = 15, stimulated with a nonreceptive female) and a sub-group with sexual motivation (SM, n = 15, stimulated with a receptive-female). Pearson correlations (r) between these parameters were calculated for each sub-group and brain structure and then compared between sub-groups. SG presented higher mount and intromission latencies than CG. While CG-WSM showed a positive r between T levels and theta band (0.23-0.59), those CG-SM presented a negative r (-0.23 to -0.67). An r that tended towards zero (-0.31 to 0.29) was obtained in both stressed sub-groups. This study shows that pubertal stress suppresses the relation between serum T levels and theta rhythms in the mPFC and BLA in adult male rats. This is one of the first studies evaluating the association between these two physiological parameters specifically in the context of sexual motivation; thus increasing our understanding of the effect of pubertal stress on prefrontal-amygdaline functioning during the sexually-motivated state in male rats.
Assuntos
Encéfalo/fisiopatologia , Comportamento Sexual Animal/fisiologia , Maturidade Sexual/fisiologia , Estresse Psicológico/fisiopatologia , Testosterona/sangue , Ritmo Teta/fisiologia , Animais , Masculino , RatosRESUMO
Abstract Introduction Stress during puberty exerts long-term effects on endocrine systems and brain structures, such as the prefrontal cortex (PFC) and basolateral amygdala (BLA), two cerebral areas that participate in modulating sexual behavior and whose functioning is regulated by androgenic hormones. Objective To evaluate the effect of pubertal stress due to social isolation on the sexual motivation, serum testosterone levels, and electroencephalographic activity (EEG) of the PFC and BLA in male rats. Method Sixty sexually-experienced male rats were used. Thirty were stressed by social isolation during puberty (SG, housed 1 per cage, postnatal days 25-50); the other 30 formed the control group (CG, 5 per cage). All rats were implanted bilaterally with stainless steel electrodes in the PFC and BLA. EEGs were recorded during the awake-quiet state in two conditions: without sexual motivation (WSM), and with sexual motivation (SM). After EEG recording, the rats were sacrificed by decapitation to measure their testosterone levels. Results SG showed lower sexual motivation and testosterone levels, but higher amygdaline EEG activation in the presence of a receptive female, while CG showed higher prefrontal EEG activation. Discussion and conclusion It is probable that the decreased testosterone levels resulting from pubertal stress affected prefrontal and amygdaline functionality and, hence, sexual motivation. These data could explain some of the hormonal and cerebral changes associated with stress-induced sexual alterations, though this suggestion requires additional clinical and animal research.
Resumen Introducción El estrés durante la pubertad ejerce efectos a largo plazo sobre sistemas endocrinos y estructuras cerebrales como corteza prefrontal (CPF) y amígdala basolateral (ABL). Ambas estructuras participan en la modulación de la conducta sexual y su funcionamiento es regulado por andrógenos. Objetivo Evaluar los efectos del estrés puberal por aislamiento social sobre la motivación sexual, los niveles séricos de testosterona y la actividad electroencefalográfica (EEG) de la CPF y ABL en ratas macho. Método Se utilizaron sesenta ratas macho sexualmente expertas, 30 fueron estresadas por aislamiento social durante la pubertad (GE, hospedados 1 por caja, días 25 al 50 postnatal), y el resto conformó el grupo control (GC, hospedados 5 por caja). Las ratas fueron implantadas bilateralmente en la CPF y ABL y el EEG fue registrado durante estado vigilia-quieto en dos condiciones: sin motivación sexual (SMS) y con motivación sexual (MS). Finalmente, las ratas se sacrificaron por decapitación para medir los niveles de testosterona. Resultados El GE presentó menor motivación sexual, menores niveles de testosterona y, en presencia de una hembra receptiva, presentaron una mayor activación EEG amigdalina, mientras que el GC mostró una mayor activación EEG prefrontal. Discusión y conclusión Es probable que la disminución de los niveles de testosterona como resultado del estrés puberal haya afectado la funcionalidad prefrontal y amigdalina y, por ende, la motivación sexual. Estos datos pudieran explicar algunos de los cambios hormonales y cerebrales asociados con alteraciones sexuales producidas por estrés. Esta propuesta deberá explorarse en futuras investigaciones animales y clínicas.
RESUMO
Resumen La motivación y la activación sexual son dos procesos semi-independientes fundamentales para la ejecución de la conducta sexual. Empleando a la rata macho Wistar como modelo animal, se determinó el efecto de diferentes dosis de alcohol (0.75 g/kg; 1.0 g/kg; 1.25 g/kg etanol), sobre el acicalamiento genital, los toques de narina (índices de motivación sexual) y las erecciones peneanas sin contacto (índices de activación sexual). Dosis altas y moderadas de alcohol provocaron un efecto deletéreo sobre ambos procesos, mientras que dosis bajas facilitaron la activación sexual. Los resultados de este trabajo confirman que la motivación y activación sexual son dos procesos semi-independientes y muestran que el alcohol ejerce un efecto diferencial sobre cada uno de ellos.
Abstract Sexual motivation and arousal are two semi-independent processes that are fundamental to the performance of sexual behavior. In this study, male Wistar rats were used as an animal model to determine the effects of different doses of alcohol (0.75, 1.0 and 1.25 g/kg ethanol) on genital-grooming and nose-touching (two indices of sexual motivation), and non-contact penile erections (an index of sexual arousal). The moderate and high doses of alcohol had deleterious effects on both processes, while the low dose, in contrast, facilitated sexual activation. The results of this study confirm that sexual motivation and arousal are two semi-independent processes, and show that alcohol exerts differential effects on each one.
Assuntos
Animais , Ratos , Etanol , Comportamento Sexual , Modelos AnimaisRESUMO
Sexual motivation requires the processing of sexual stimuli. The prefrontal cortex (PFC) and nucleus accumbens (NAcc) receive dopaminergic innervation from the ventral tegmental area (VTA). Both structures participate in processing stimuli, and their adequate functioning is modulated by dopamine and other neurotransmitters. This study was designed to determine the effect of inactivation of the VTA on sexual motivation, relative power (RP) and electroencephalographic (EEG) correlation of the PFC and NAcc in male rats. A total of 20 rats implanted with electrodes in the left medial prefrontal cortex (mPFC) and NAcc, and with bilateral cannulae in the VTA, were divided into two groups of 10 rats each, one injected with tetrodotoxin (TTX), the other with a vehicle solution (VEH). EEGs from the mPFC and NAcc were recorded during the awake-quiet state in the presence of either a receptive or non-receptive female. The TTX group showed a lower preference for the receptive female accompanied by a lower RP of the 8-13 and 14-30â¯Hz bands in the mPFC. Also, in the presence of the receptive female, the TTX group had a lower RP of the 8-13â¯Hz band in the NAcc, but a higher prefronto-accumbens correlation in the same band. These results provide evidence that VTA activity is necessary for the adequate functioning of the mPFC and NAcc and, therefore, also for the adequate processing of sexually-relevant stimuli that allows the induction and maintenance of sexual motivation in male rats.
Assuntos
Núcleo Accumbens/fisiologia , Córtex Pré-Frontal/fisiologia , Comportamento Sexual Animal/fisiologia , Área Tegmentar Ventral/fisiologia , Animais , Eletrodos Implantados , Eletroencefalografia , Feminino , Masculino , Motivação , Ratos , Tetrodotoxina/farmacologiaRESUMO
Administering clomipramine during the early days of life induced several behavioral and neurochemical alterations in adult male rats, which resemble major depression disorder. The alterations included poor sexual performance, which is considered a reward-seeking behavior regulated by dopaminergic system. Given that estrogen receptors are expressed in different areas of the brain involved in regulating reproductive behavior, motivation and mood. The objective of this study was to analyze the effect of a non-selective dopamine agonist (apomorphine) on sexual incentive motivation in rats exposed to clomipramine (CMI) in the neonatal period. In addition, we evaluated the expression of mRNA ERα and ERß in nucleus accumbens (NAcc) and septum of CMI rats. We found that only a few rats subjected to neonatal CMI treatment performed mounts, intromissions and ejaculations. Also, those rats spent less time exploring the sexual incentive zone and had lower preference scores; this effect was reverted by administering 0.1â¯mg/kg of apomorphine. Finally, the CMI rats presented higher levels of mRNA ERα and ERß, only in septum area. These data indicate that neonatal treatment with CMI altered the expression of mRNA ERα and ERß in the septum, which participates in regulating the motivational component of sexual behavior.
Assuntos
Apomorfina/farmacologia , Clomipramina/farmacologia , Copulação/efeitos dos fármacos , Agonistas de Dopamina/farmacologia , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/genética , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Septo do Cérebro/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Apomorfina/administração & dosagem , Clomipramina/administração & dosagem , Agonistas de Dopamina/administração & dosagem , Feminino , Masculino , Motivação/efeitos dos fármacos , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , RNA Mensageiro/genética , Ratos , Ratos Wistar , Recompensa , Septo do Cérebro/metabolismo , Inibidores Seletivos de Recaptação de Serotonina/administração & dosagem , Transdução de Sinais/efeitos dos fármacosRESUMO
Abstract: Introduction: Although child maltreatment is related with psychopathologic symptoms, however their clinical prevalence in the general population and more so in specific groups of age and gender, such as female adolescents, has been scarcely documented. Objective: The purpose of the present study was to examine the prevalence mental illness symptoms ‒such as post-traumatic stress disorder, depression, and anxiety‒ in female adolescent maltreatment victims in Mexico. Method: Fifty-five 12-17-year old female adolescent victims of maltreatment (sexual, physical, and emotional abuse) recruited from four different Mexican institutions were evaluated through clinical scales for post-traumatic stress, depression, and anxiety, in addition to clinical interviews. Results: More than half of the participants presented significant scores of psychopathological symptoms in the three scales evaluated. Discussion and conclusion: The high prevalence of psychopathologic symptoms found in this study suggests that female adolescents who had experienced some form of abuse present highed a susceptibility to develop psychopathology. Results are discussed in the context of their relevance as a public health problem and their implications for professional interventions.
Resumen: Introducción: Aunque el maltrato infantil se ha asociado con síntomas psicopatológicos, se ha documentado poco la prevalencia clínica que tiene en la población general y aún más en grupos específicos de edad y género, como en el caso de mujeres adolescentes. Objetivo: El presente estudio tiene como propósito examinar la prevalencia de síntomas de enfermedades mentales como el trastorno de estrés postraumático, la depresión y la ansiedad en adolescentes víctimas de maltrato en México. Método: Se evaluaron 55 mujeres adolescentes víctimas de maltrato (abuso sexual, físico y emocional) de 12 a 17 años, reclutadas en cuatro diferentes instituciones mexicanas. A todas se les aplicaron entrevistas y escalas clínicas de estrés postraumático, depresión y ansiedad. Resultados: Más de la mitad de las participantes presentaron altos puntajes de síntomas psicopatológicos en las tres escalas evaluadas. Discusión y conclusión: La alta prevalencia de síntomas psicopatológicos encontrada en este estudio sugiere que las adolescentes que experimentaron alguna forma de abuso presentaron una alta susceptibilidad a desarrollar psicopatología. Se discuten los resultados en el contexto de su relevancia como un problema de salud pública y sus implicaciones para las intervenciones profesionales correspondientes.