Alterations of learning and memory are accompanied by alterations in the expression of 5-HT receptors, glucocorticoid receptor and brain-derived neurotrophic factor in different brain regions of an animal model of depression generated by neonatally male treatment with clomipramine in male rats.

Depressive illness has been associated with impaired cognitive processes accompanied by reduced neurotrophin levels, especially brain-derived neurotrophic factor (BDNF), and dysfunctions in the hypothalamic-pituitary-adrenal (HPA) axis. In addition, depression is characterized by a decreased functioning of the serotonergic system due to changes in the activity or expression of its receptors including, most significantly, 5-HT1A, 5-HT2A, and 5-HT3 in brain regions that regulate mood, emotions, and memory, such as the prefrontal cortex, hippocampus, and amygdala. In this regard, rats treated with clomipramine (CMI) in the neonatal stage show depression-like behaviors that persist into adulthood; hence, this constitutes an adequate model of depression for exploring various molecular aspects associated with the etiology of this disorder. This, study, then, was designed to analyze the long-term effects of early postnatal exposure to CMI on the expression of 5-HT1A, 5-HT2A, and 5-HT3 receptors, as well as BDNF and GR in the following brain regions: PFC, amygdala, hippocampus, and hypothalamus, which could be related to alterations in memory and learning, as evaluated using the novel object recognition (NOR) and Morris water maze (MWM). Expression of the 5-HT1A, 5-HT2A, and 5-HT3 receptors, BDNF, and the glucocorticoid receptor (GR) was assessed by RT-qPCR in the four aforementioned brain regions, all of which play important roles in the control of memory and mood. Findings show that neonatal treatment with CMI causes alterations in memory and learning, as indicated by alterations in the results of the MWM and NOR tests. Expression of the 5-HT1A receptor increased in the hippocampus, amygdala, and hypothalamus, but decreased in the PFC, while the 5-HT2A and BDNF receptors decreased their expression in the PFC, amygdala, and hippocampus. There was no change in the expression of the 5-HT3 receptor. In addition, expression of GR in the hippocampus and PFC was low, but increased in the hypothalamus. Taken together, these data show that neonatal CMI treatment produces permanent molecular changes in brain regions related to learning and memory that could contribute to explaining the behavioral alterations observed in this model.

Effects of postnatal exposure to cadmium on male sexual incentive motivation and copulatory behavior: Estrogen and androgen receptors expression in adult brain rat.

There are numerous evidence showing that cadmium (Cd) is an endocrine disruptor that exerts multiple toxic effects at different reproductive levels, including male sexual behavior (MSB). The effect of early exposure to Cd on sexual incentive motivation (SIM) and MSB in adult stage, and the immunoreactivity of receptors for hormones such as estrogens and androgens in brain regions that are relevant for the SIM and MSB display, have not been studied until now. The present study evaluated the effects of 0.5 and 1 mg/kg CdCl2 from day 1-56 of postnatal life on SIM and MSB in adults rats, as well as serum testosterone concentrations, Cd concentration in blood, testis, and brain areas, and the immunoreactivity in estrogen receptors (ER-α and -ß), and androgen receptor (AR) in the olfactory bulbs (OB), medial preoptic area (mPOA), and medial amygdala (MeA). Our results showed that both doses of Cd decreased SIM and MSB, accompanied by low serum concentrations of testosterone. Also, there was a significant reduction in immunoreactivity of ER-α and AR in mPOA, and a significant reduction in AR in MeA on male rats treated with Cd 1 mg/kg. These results show that exposure to high doses of Cd in early postnatal life could alter the correct integration of hormonal signals in the brain areas that regulate and display SIM and MSB in adult male rats.

Male rats exhibit higher prefrontal-parietal EEG synchronization during the sexually-motivated state.

Sexual motivation (SM) is a physiological state generated by the adequate processing of sexually-relevant stimuli. Induction and maintenance of this state requires the coordinated functioning of various cortical and subcortical areas. The medial prefrontal (mPFC, the prelimbic area in rats) and posterior parietal cortices (pPC) form an attentional network involved in processing incentive stimuli. Given that the sexual incentive stimuli emitted by a receptive female are highly relevant for the male rat, it is probable that these cortices interact functionally in processing the sexual stimuli that produce SM. Thus, the objective of this study was to characterize the cortical activation and degree of electroencephalographic coupling (coherence, hEEG) between the mPFC and pPC during a sexually-motivated state in male rats. Only rats that reached this state after 1 intromission prior to EEG recording, presented a higher frequency and duration of nose pokes, and showed higher prefronto-parietal activation and EEG synchronization while close to an inaccessible receptive female. Results show that both cortices are activated and that they are functionally coupled during the processing of sexually-relevant stimuli mainly in the right hemisphere, a key condition for inducing SM. We conclude that the attentional network made up of the prefrontal and parietal cortices participates in the adequate attention to, and processing of, sexual incentive stimuli and, hence, in inducing SM in male rats.

Effect of Chronic Moderate Caloric Restriction on the Reproductive Function in Aged Male Wistar Rats.

Caloric restriction (CR) has been shown to be an effective nutritional intervention for increasing longevity in some animal species. The objective of this study was to evaluate CR's effects on metabolic and reproductive parameters in 12-month-old male Wistar rats. The rats were distributed in three groups: control, CR at 15%, and CR at 35% for 6 (up to 18 months of age) and 12 months (up to 24 months of age). At the end of CR treatment, we evaluated reproductive (male sexual behavior (MSB), sperm quality) and biochemical parameters (plasma glucose, glucose-regulating hormone, and sex steroid levels), and quantified annexin V in the seminiferous epithelium. Results showed that MSB and sperm quality were improved after 6 months of CR associated with increases in plasma testosterone and decrease annexin V in the seminiferous epithelium of the testicles compared to their control group. The metabolic profile of the CR rats also improved compared to controls. However, these effects of CR on reproductive parameters were not maintained after 12 months of CR. Findings suggest that beginning CR at the age of maturity reestablishes the behavioral sexual response and reproductive function in older animals after 6 months of CR and improves endocrine functioning during aging.

Postnatal cadmium administration affects the presence and distribution of carbohydrates in the sperm membrane during maturation in the epididymis in adult Wistar rats.

Cadmium (Cd) is a heavy metal related to a decrease in sperm parameters. The transit of spermatozoa through the epididymis is necessary to generate changes in the sperm membrane, such as the assembly of various carbohydrates that are added to the spermatazoan's surface to prepare it for successful fertilisation of the oocyte. No studies have yet analysed whether Cd alters the presence and distribution of these carbohydrates. We aimed to evaluate the changes induced by Cd in the distribution pattern of N-acetylglucosamine, sialic acid, mannose and fucose on the sperm membrane in the epididymis (e.g. caput, corpus, cauda) and if it alters the epididymal epithelium. Male Wistar pups were treated with Cd doses (0.125, 0.25 and 0.5mg/kg) on postnatal days 1-49. At postnatal day 90, they were humanely killed, sperm samples were obtained from the epididymis and tissue samples were taken for histological analysis. Cd concentrations in the blood and epididymis increased in proportion to the dose administered and decreased the serum testosterone levels and sperm quality. Histological analysis revealed alterations in the epithelium in all Cd-treated groups. Cd altered the distribution patterns of carbohydrates and fluorescence indices. All these alterations affected the structure and functioning of sperm.

Delay in puberty indices of Wistar rats caused by Cadmium. Focus on the redox system in reproductive organs.

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 1 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.

Cadmium exposure negatively affects the microarchitecture of trabecular bone and decreases the density of a subset of sympathetic nerve fibers innervating the developing rat femur.

Cadmium (Cd) is toxic to the skeletal system resulting in bone loss and pain. We aimed at determining the effect of chronic Cd exposure on bone density and microarchitecture along with changes in the density of a subset of sensory and sympathetic nerve fibers innervating the developing rat femur. Newborn male Wistar rats were injected daily for 49 days with CdCl2 (1 mg/kg i.p.) or saline solution (control group). At the day of sacrifice, levels of Cd in the right femur, liver and kidney were determined by atomic absorption spectrophotometry. Additionally, microCT followed by immunohistochemical analyses were performed in the left femur. Results showed Cd accumulation in trabecular bone neared levels seen in liver and kidney. Cd concentration in cortical bone was significantly lower versus trabecular bone. MicroCT analysis revealed that Cd-exposed rats had a significant decrease in trabecular bone parameters at the distal femoral metaphysis; however, most of the cortical bone parameters were not significantly affected. Cd-exposed rats showed a significant loss of TH+ sympathetic nerve fibers, but not of CGRP+ sensory nerve fibers, at the level of bone marrow of the femoral diaphysis as compared to control rats. This study shows that Cd negatively affects bone density and microarchitecture of trabecular bone and decreases the density of sympathetic nerve fibers innervating rat femur. Future studies are warranted to determine the toxigenic mechanisms of Cd on sympathetic nerves and how sympathetic denervation influences bone loss in animals exposed to Cd.

Neuroendocrine effects of cadmium exposure on male reproductive functions.

In industrialized countries, the use of Cadmium (Cd) produces a form of anthropogenic pollution. Hence, exposure by human populations is becoming a public health problem. With a half-life of up to 40 years, cadmium is now a topic of great interest due to its role as an endocrine disruptor and its effects on male reproduction. Cd's diverse toxic mechanisms are based on its capacity to mimic divalent ions -calcium, zinc, iron- that participate in physiological processes. It alters the mitochondrial function and generates the production of free radicals that can induce apoptosis. In male reproduction, Cd alters the precise coordination of the hypothalamic-hypophysis-testis axis (HHT), resulting in the loss of testicular functions like steroidogenesis, spermatogenesis and the onset of puberty, sexual maturity, sexual behavior and fertility. Exposure to Cd may even cause changes in the immune system that are associated with the reproductive system. This review analyses the state of the question regarding Cd's cellular and physiological mechanisms and the effects of this heavy metal on the neuroendocrine regulation of male reproduction.

Protection induced by estradiol benzoate in the MPP+ rat model of Parkinson's disease is associated with the regulation of the inflammatory cytokine profile in the nigro striatum.

Previously, we have demonstrated that ß-estradiol-3-benzoate (EB) has a protective effect on the neurodegenerative experimental model of Parkinson's disease. The protective effect is through the induction of the expression of paraoxonase-2 (PON2) in the striatum. PON2 has proven to have antioxidant and anti-inflammatory activity, this protein has a beneficial effect in MPP+ model in rats decreasing the lipid peroxidation and the oxidative stress. Furthermore, the molecular effect and the pathway by which EB induces protection were not further pursued. This study shows the regulation by EB of the anti-inflammatory effect through the modulation of cytokines, antioxidant enzymes and PON2 in the rat striatum. Rats were gonadectomized and 30 days after were randomly assigned into four experimental groups; only vehicles (Control group); EB treatment (EB group); MPP+ injury (M group); EB plus MPP+ injured (EB/M group). EB treatment consisted of 100 µg of the drug administered every 48 h for 11 days. Results showed that EB (group EB/M) treatment decrease significantly (40%) the number of ipsilateral turns respect to the M group and prevents significantly the dopamine (DA) decreased induced by MPP+ (~75%). This results are correlate with a significant decrease in the level of lipid peroxidation (60%) of the EB/M group respect to the M group. The EB treatment showed protection against neurotoxicity induced with MPP+, this could be due to EB capacity to prevent the increase in the expression level of proinflammatory cytokines TNF-α, IL-1 and IL-6 induced by MPP+. While, TGF-ß1 and TGF-ß3 expression was reduced in the rats treated only with MPP+, in the rats of EB/M group the expression of both cytokines was increased. EB protective effect against MPP+ neurotoxicity is related to antioxidant effect of PON2, pro-inflammatory cytokines and GSHR but not to SOD2, catalase, GPX1 or GPX4.

Electroencephalographic changes and testosterone levels in a pubertal stress animal model: effects on adult sexual motivation / Cambios electroencefalográficos y niveles de testosterona en un modelo animal de estrés puberal: efectos sobre la motivación sexual adulta

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.

Neonatal treatment with clomipramine modifies the expression of estrogen receptors in brain areas of male adult rats.

The participation of estrogens in depression has been well recognized. To exert its effects, estradiol binds mainly to estrogen receptors ESR1 and ESR2 (α and ß, respectively), expressed in brain regions including the hippocampus, limbic regions and hypothalamic nuclei. In rodents, modified estrogen receptors expression in brain areas have been implicated in different signs similar to those observed in depressive patients. Neonatal clomipramine (CMI) treatment is a pharmacological manipulation that generates behavioral and neurochemical changes that persist throughout adulthood and resemble human depression. The aim of this study was to analyze whether CMI neonatal treatment modifies the expression of nuclear ESR1 and ESR2 in the hippocampus, amygdala basolateral (BLA), amygdala medial (MeA), hypothalamic medial preoptic area (mPOA) and raphe nucleus in male rats. Our results indicate that CMI treatment significantly induced an mRNA increase of ESR1 in the hypothalamus, additionally produce a reduction in the mRNA ESR2 expression in raphe accompanied of an increase in hypothalamus and amygdala. CMI treated rats show more immunorreactive cells to ESR1 (ESR1-ir) in mPOA, BLA, MeA, together with a reduction of these cells in the hippocampal CA1 region. Moreover, an increase in the number of immunorreactive cells to ESR2 (ESR2-ir), in BLA and MeA, was observed in CMI treated rats. Additionally, the hippocampal CA2 region and raphe nucleus showed a decrease in these cells. Also, neonatal CMI treatment induced a decrease in the number of cells of the pyramidal layer in CA1. Overall, the results suggest that neonatal CMI treatment in rats (during brain development) induces changes in estrogen receptors in different brain areas involved with the regulation of depressive-like behaviors.

Effect of different anesthetic mixtures-ketamine-xylazine, ketamine-acepromazine and tiletamine-zolazepam-on the physiological and blood biochemistry parameters of male rhesus monkeys (Macaca mulatta) at different ages.

BACKGROUND: Anesthetic agents are commonly utilized in the handling of non-human primates for prevent the stress caused in physical exploration or physical restrain. For this reason, the objective of this work was to describe the effect of age and dissociative anesthetics (ketamine and tiletamine), and their combinations with acepromazine, xylazine and zolazepam, on the physiological and blood biochemical parameters in Macaca mulatta. METHODS: Eighty male Macaca mulatta were divided into four experimental groups depending on the anesthetic mixture applied. Each group of 20 males was divided into five sub-groups according to age. Physiological parameters were recorded every 5 minutes during a 30-minute period. A blood sample was drawn to analyze blood biochemistry. RESULTS: Statistical analyses revealed significant differences in the physiological parameters between the ketamine-acepromazine and ketamine-xylazine groups compared to the control group. The analysis of blood biochemistry found significant differences by age and by anesthetic mixture among all groups. CONCLUSION: These findings contribute to standardizing this animal model in biological research.

Paternal behavior in the Mongolian gerbil, and its regulation by social factors, T, ERα, and AR.

The present study evaluates the role of social factors in the transition from infanticidal to paternal male behavior and its association with T concentration, presence of estrogen receptor alpha (ERα) and androgen receptor (AR) in the olfactory bulb (OB), medial preoptic area (mPOA) and medial amygdala (MeA) of Mongolian gerbils (Meriones unguiculatus). This study included thirty-six sexually inexperienced males displaying aggressive behavior toward foreign pups. The selected animals were mated and organized into four groups. The paternal behavior tests were performed on the day of copulation (DCOPUL), during cohabitation with a pregnant female (CPREG), on the day of birth (DBIRTH), and on day 6 postpartum (DPP6). Eight sexually inexperienced males (CTL (male-male cohabitation) were used as control. After paternal behavior tests, blood samples were obtained to quantify T by radioimmunoassay; the brains were removed and analyzed for immunoreactivity (ir) of ERα and AR. All males of the DCOPUL, DBIRTH, and DPP6 groups exhibited paternal behavior, whereas the males of CPREG and CTL groups were aggressive with the pups. Paternal behavior was associated with high T concentrations, and the presence of ERα-ir and AR-ir in the OB, MeA, and mPOA. These results suggest that the transition from aggressive to paternal response to pups is facilitated by copulation, and that in this transition is involved an increase in T concentration. Moreover, the presence of ERα-ir and AR-ir in the OB, mPOA, and MeA could indicate that estrogenic and androgenic pathways participate in the regulation of paternal behavior of the Mongolian gerbils.

Computed tomography is a feasible method for quantifying bone density in Macaca mulatta.

Osteopathologies are a result of advanced age and decreased bone density and represent a global health problem. It is therefore important to generate models for longitudinal studies of the pathophysiology in order to improve early diagnosis and develop preventive therapies. For this kind of research, the use of computed tomography (CT) to evaluate bone health offers advantages over other techniques since it provides more complete information. The aim of this prospective, pilot study was to obtain measurements of the left femur from a population in captivity of 32 rhesus monkeys (Macaca mulatta) in order to standardize the model for future research. Healthy subjects from 5 to 28 years old were chosen. Three groups with different ages were formed as follows: (1) 5-9 years, (2) 10-19 years, and (3) 20-28 years. Semi-automatic segmentation by threshold defined the regions of interest, which were subdivided in the range of 300-700 Hounsfield units (HU) for trabecular bone and >700 HU for cortical bone. Then, the proportional ratios of the volumes of trabecular bone and cortical bone were obtained. Significant differences (analysis of variance test) in the averages of Hounsfield units, cortical, and trabecular bone proportions from each age group proved that a decrease in bone density begins at approximately 20 years of age. The values presented here, as well as the method to obtain them from CT scans, can be used as a baseline in a primate model for long-term research in bone pathology diagnosis and treatment.

Prenatal stress suppresses the prefrontal and amygdaline EEG changes associated with a sexually-motivated state in male rats.

The medial prefrontal cortex (mPFC) and basolateral amygdala (BLA) participate in the modulation of several motivated behaviors, such as the sexual behavior. Both structures are sensitive to stress when it is experienced mainly in critical periods of the life-cycle, such as the prenatal period. This study evaluated the effects of prenatal stress on electroencephalographic activity (EEG) of the mPFC and BLA during sexual motivation. EEG was recorded in the mPFC and BLA of male rats assigned to either a prenatally-stressed group (SG, dam immobilized from days 14 to 21of pregnancy), or a control group (CG), during the following conditions: awake-quiet state without sexual motivation, and awake-quiet state with sexual motivation. Compared to CG, fewer SG subjects presented copulatory responses and their levels of sexual motivation were lower. The CG subjects with sexual motivation showed a higher absolute power (AP) of the 14-30Hz band in the left mPFC and BLA than those without sexual motivation. The SG showed a lower AP of the 4-7 and 8-13Hz bands in the left BLA. Thus, prenatal stress suppressed the prefrontal and amygdaline EEG changes associated with a sexually-motivated state. EEG data show that stress affects the functioning of these two brain structures and so could interfere with the adequate processing of sexual stimuli. These findings contribute to understanding the brain mechanisms that underlie the effect of prenatal stress on the processing of sexual stimuli in male rats.

ß-Estradiol-3-benzoate confers neuroprotection in Parkinson MPP+ rat model through inhibition of lipid peroxidation.

Estradiol (E2), in addition to its known hormone function, is a neuroactive steroid that has shown neuroprotective profile in several models of neurological diseases. The present study explores the antioxidant effect of ß-estradiol-3-benzoate (EB) on the neurotoxicity elicited by MPP+ in rat striatum. Male Wistar rats, that were gonadectomized 30days prior to EB, were given 100µgEB per rat every 48h for 11days and animals were infused with MPP+ via intrastriatal at day six after beginning EB treatment. EB treatment completely prevented the fall in dopamine caused by MPP+, such result was related with decreased lipid peroxidation, a marker of oxidative stress; diminished number of ipsilateral-to-lesion turns and increased signal of the dopamine-synthesizing enzyme Tyrosin Hydroxylase in substantia nigra. The protection elicited by EB was not related to Mn or Cu-Zn superoxide dismutase enzymatic activities or glutathione modulation since none of these parameters were influenced by EB at the times assayed. Whereas, increased expression of PON2 as a result of EB treatment was observed, this phenomenon could be one of the mechanism by which the steroid conferred protection to dopaminergic cells against MPP+ injury.

Changes in hormonal levels associated with enforced interval copulation and anxiety in sexually inexperienced and experienced male rats.

This study evaluated the effect of sexual experience on anxiety and hormonal levels associated with the performance of sexual behavior. Two groups of male rats, one with, the second without, sexual experience, were exposed to four different copulatory conditions: ad libitum copulation until ejaculation (ADC-E); enforced interval copulation until ejaculation (EIC-E); ad libitum copulation up to 3 intromissions (ADC-3I); and enforced interval copulation up to 3 intromissions (EIC-E3I). At the end of each condition the animals were subjected to an open-field test to measure anxiety, before being sacrificed to measure corticosterone (CORT) and testosterone (T) levels. The sexually-inexperienced males showed less hyperactivity, lower sexual motivation, and higher anxiety levels. Only in the ADC-E and EIC-E conditions did both the inexperienced and experienced rats have a higher number of entries to the central squares of the open-field test. Both the sexually-inexperienced and experienced male rats showed an increase in CORT levels, but only the latter had increased T levels under all copulatory conditions. These findings reveal that the anxiolytic effect of mating is dependent on previous sexual experience and the degree of control that the male rats had during sexual interaction. The changes in the levels of both hormones could be part of the physiological process necessary to satisfy the demands involved in sexual performance and open filed. These data provide further insight into the role of sexual experience in mediating the release of CORT and T, as well as the anxiolytic effects of ejaculation.

Reactive oxygen species production and antioxidant enzyme activity during epididymal sperm maturation in Corynorhinus mexicanus bats.

Prolonged sperm storage in the epididymis of Corynorhinus mexicanus bats after testicular regression has been associated with epididymal sperm maturation in the caudal region, although the precise factors linked with this phenomenon are unknown. The aim of this work is to determine the role of reactive oxygen species (ROS) and changes in antioxidant enzymatic activity occurring in the spermatozoa and epididymal fluid over time, in sperm maturation and storage in the caput, corpus and cauda of the bat epididymis. Our data showed that an increment in ROS production coincided with an increase in superoxide dismutase (SOD) activity in epididymal fluid and with a decrease in glutathione peroxidase (GPX) activity in the spermatozoa in at different time points and epididymal regions. The increase in ROS production was not associated with oxidative damage measured by lipid peroxidation. The results of the current study suggest the existence of a shift in the redox balance, which might be associated with sperm maturation and storage.

Neonatal exposure to monosodium glutamate induces morphological alterations in suprachiasmatic nucleus of adult rat.

Neonatal exposure to monosodium glutamate (MSG) induces circadian disorders in several physiological and behavioural processes regulated by the suprachiasmatic nucleus (SCN). The objective of this study was to evaluate the effects of neonatal exposure to MSG on locomotor activity, and on morphology, cellular density and expression of proteins, as evaluated by optical density (OD), of vasopressin (VP)-, vasoactive intestinal polypeptide (VIP)- and glial fibrillary acidic protein (GFAP)-immunoreactive cells in the SCN. Male Wistar rats were used: the MSG group was subcutaneously treated from 3 to 10 days of age with 3.5 mg/g/day. Locomotor activity was evaluated at 90 days of age using 'open-field' test, and the brains were processed for immunohistochemical studies. MSG exposure induced a significant decrease in locomotor activity. VP- and VIP-immunoreactive neuronal densities showed a significant decrease, while the somatic OD showed an increase. Major axes and somatic area were significantly increased in VIP neurons. The cellular and optical densities of GFAP-immunoreactive sections of SCN were significantly increased. These results demonstrated that newborn exposure to MSG induced morphological alterations in SCN cells, an alteration that could be the basis for behavioural disorders observed in the animals.

Hormone replacement with 17ß-estradiol plus dihydrotestosterone restores male sexual behavior in rats treated neonatally with clomipramine.

Male sexual behavior (MSB) in rodents, in both its consummatory and motivational components, is regulated by hormones such as testosterone, 17ß-estradiol and 5-α-dihydrotestosterone. In experiments, neonatal treatment with clomipramine (CMI; a serotonin reuptake inhibitor) reproduces some of the signs of depression in adult age, including reduced sexual behavior manifested in a lower percentage of subjects that mount, intromit and ejaculate, although their testosterone levels were not altered. However, the effect of this treatment on estrogen levels and the consequences of hormone substitution using 17ß-estradiol and 5-α-dihydrotestosterone on the expression of male sexual behavior are still unknown. Therefore, the objective of the present study was to analyze the effect of neonatal treatment with CMI on plasma testosterone and 17ß-estradiol levels, and the role of testosterone, 17ß-estradiol and 5-α-dihydrotestosterone in altering the consummatory and motivational components of sexual behavior in male rats. To this end, it analyzed the copulatory parameters and sexual incentive motivation (SIM) of rats treated with CMI under two conditions: basal and post-hormone replacements. Neonatal treatment with CMI did not affect plasma testosterone or 17ß-estradiol concentrations, but did decrease both the consummatory component and sexual motivation according to the results of the SIM test. These aspects were recovered after administering 17ß-estradiol +5-α-dihydrotestosterone, but not testosterone.