Effects of post-ovariectomy time frame and age on the antidepressant-like actions of estradiol and prolame in female rats.

Estrogen replacement therapy (ERT) is an effective treatment for symptoms associated with climacteric and depression some women experience during perimenopause and menopause. The antidepressant-like effects of ERT may depend on the type of estrogen, age, and time when restitution is initiated after hormonal decline. Prolame is a synthetic steroid with estrogenic and antidepressant-like effects that may produce fewer adverse effects. We hypothesize that such actions of prolame on females depend on age and the duration of hormone deprivation period. We assessed the antidepressant-like effects of 17ß-estradiol (E2) and prolame in young and middle-aged rats across different post-ovariectomy (Ovx) time frames. Independent groups of young adults and middle-aged female rats were tested in the forced swimming test (FST) at 3, 8, 16, and 24 weeks post-Ovx. Prolame and E2 were administered in a sub-chronic schedule consisting of three injections before the FST. Likewise, the utero-trophic effects of these hormones were analyzed. We found that E2 and prolame reduced immobility in young rats 3 and 8 weeks after Ovx; in contrast, only prolame produced this effect in middle-aged rats three weeks post-Ovx. E2 and prolame increased the animals' utero-somatic index at all post-Ovx times, but the action of E2 and prolame produced a greater response in young adult rats. Our findings showed that the antidepressant-like effects of E2 and prolame depend on the post-Ovx time frame, age, and estrogen type. Interestingly, our results indicate that, in contrast to E2, prolame maintained its antidepressant effect in middle-aged rats.

Age-dependent effects of testosterone on spatial memory in male rats.

Decreased spatial memory is common in aging populations and reduces their quality of life. Although its role is still controversial, low testosterone (T) may contribute to impaired cognition in aged men. This study aimed to identify the role of T in age-related deficiencies in spatial memory among male rats. Young adult (3 months old) and aged (21 months old) Wistar rats were assigned to independent groups: intact, orchidectomized, or orchidectomized + subcutaneous pellets of T propionate. The phases of spatial memory acquisition (4 daily trials/4 days) and spatial memory retention (1 trial/day, 3 and 12 days after acquisition) were evaluated using the Barnes maze. Compared with young adults, aged intact rats took longer to find the goal, made more mistakes, and showed only slight improvements in goal sector exploration across the acquisition period. The young orchidectomized rats showed no improvement in performance over the days during the acquisition phase. T treatment in hormonally deprived old rats produced a small improvement in goal sector exploration and number of errors during the acquisition phase. Meanwhile, in young adults, this treatment improved the goal sector searching in the retention phase (12 days after acquisition training). Our results suggested that age-related spatial memory deficits cannot be entirely explained by the decline in T levels; however, this androgen produced subtle and mild beneficial effects on spatial memory in young and old males. Taken together, our findings suggest age differences in the role of T on spatial memory in males.

Serum testosterone levels in bipolar and unipolar depressed female patients and the role of medication status.

Objective: to compare testosterone levels between female depressed patients and female bipolar patients.Methods: Sixty-one female patients with major depressive disorder (MDD) (n = 23) or bipolar disorder (BD) (n = 38) between 18 and 45 years old were included in the study. Participants were evaluated during a depressive or manic episode with the Hamilton depression rating scale (HDRS) or Young mania rating scale (YMRS), respectively. No patients in the MDD group were taken valproate while in the BD group 14 (36.84%) were taken valproate. Total testosterone (TT) and free testosterone (FT) levels were quantified during the early follicular phase of the cycle, with radioimmunoassay or solid phase enzyme-linked immunoassay. Data were collected from May 2016 to February 2017.Results: Mean TT serum levels were significantly higher in BD patients in comparison to MDD patients. Although age and diagnosis were related to TT levels, however when we added valproate use in the analysis, only the relation between TT and valproate use remained significant.Conclusions: In this sample, TT levels were related to valproate use in patients with BD. More studies regarding the role of testosterone in affective symptoms should be conducted to clarify the relation between testosterone, affective disorders, and medication.KeypointsWe observed that testosterone levels were significant higher in bipolar women compared to women with MDD.The use of valproate could be associated with the testosterone levels in female patients with BD.Evaluation of women suffering BD should include a testosterone levels determination, particularly when they are taking valproate.

Influence of the type of childhood violence on cannabis abuse and dependence among adolescents: a systematic review and meta-analysis. / Tipos de violencia en la infancia que inciden en el abuso y dependencia de cannabis entre adolescentes: una revisión sistemática y metaanálisis.

The use of cannabis for recreational purposes has increased worldwide, and the proportion of cannabis users in the adolescent population is high. Susceptibility to cannabis use involves various factors, including childhood adversity; however, the effects of different types of violence on cannabis use have not been evaluated. The aim of this review was to analyze the effects of different types of violence on cannabis use in adolescence. We searched electronic databases (PubMed, Science Direct, Web of Science, Ovid and CONRICyT) using the following algorithm: (("Cannabis" OR "Marijuana Smoking" OR "Marijuana Abuse") AND ("Child Abuse" OR "Domestic Violence" AND "Adolescent")), considering all articles published up to November 3th, 2017. Odds ratios (ORs) were calculated for the effects of experiencing different types of violence during childhood on cannabis use. Six studies, which represented 10 843 adolescents of both sexes, were ultimately included in the systematic review and meta-analysis. Three types of early-life adversity were associated with cannabis abuse/dependence: physical abuse (OR: 1.58, 95% CI [1.01-2.46]), sexual abuse (OR: 2.35, 95% CI [1.64-3.35]), and witnessing violence (OR: 3.22, 95% CI [0.63-16.54]). The results indicated that two specific types of child maltreatment, sexual and physical abuse, were critical factors affecting vulnerability to cannabis use in adolescence. The number of studies examining other types of violence was limited. The results highlighted the importance of enhancing efforts to prevent violence, particularly sexual abuse, as part of integral programs designed to prevent cannabis abuse and dependence.

El uso recreativo de cannabis ha incrementado en todo el mundo, principalmente en la población adolescente. Se ha propuesto que la adversidad en la infancia contribuye al consumo de esta droga. El objetivo de esta revisión sistemática y metaanálisis fue analizar el efecto de diferentes tipos de violencia en la infancia sobre el consumo de cannabis en la adolescencia. Se realizó una búsqueda en diferentes bases de datos (PubMed, Science Direct, Web of Science, Ovid y CONRICyT) usando los términos de búsqueda: (("Cannabis" OR "Marijuana Smoking" OR "Marijuana Abuse") AND ("Child Abuse" OR "Domestic Violence" AND "Adolescent")), considerando todos los artículos publicados hasta el 3 de noviembre de 2017. Se calcularon los Odds Ratio (OR) del consumo de cannabis en adolescentes, para los diferentes tipos de abuso infantil, así como sus intervalos de confianza del 95% (IC 95%). Se identificaron seis estudios, que incluyeron 10 843 adolescentes de uno u otro sexo. La asociación entre la violencia y el abuso/dependencia de cannabis en la adolescencia mostró los siguientes valores: abuso físico (OR: 1,58, IC 95% [1,01­2,46]), abuso sexual (OR: 2,35, IC 95% [1,64­3,35]), y ser testigo de violencia (OR: 3,22, IC 95% [0,63­16,54]). Los resultados muestran que el abuso sexual o físico durante etapas tempranas de la vida aumenta el riesgo de consumo de cannabis en la adolescencia. Los estudios que evaluaron otras formas de violencia fueron escasos. Los resultados destacan la importancia de diseñar programas integrales para reducir el uso y dependencia de cannabis mediante estrategias enfocadas a la prevención de la violencia en la infancia.

Relationship between androgen deficiency and memory impairment in aging and Alzheimer’s disease.

Aging and Alzheimer’s disease (AD) are associated with a declination of cognition and memory, whose severity increases in AD. Recent investigations point to a greater participation of neurofibrillary tangles (NFTs) than that of senile plaques, as responsible for cognitive impairment in AD and normal aging. On the other hand, aging is related with reduced levels of dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) as well as testosterone (T). Basic and clinical studies give evidence that hypoandrogenism is associated with memory impairment. Accordingly, some animal studies show that the administration of these hormones improves the performance of cognitive tasks. However, effects of DHEA, DHEA-S, and T in the clinical setting, are not clear in part because of the balance between the benefits and risks of hormone therapy in aging subjects and because the cellular mechanism underlying its effects on memory in old age and related pathologies are unknown. The objective of this review is to analyze the role of DHEA, DHEA-S, and T, on memory in normal aging and in AD, and to determine whether these hormones modulate the hyperphosphorylation of tau protein, a molecular marker in AD pathology. The method used in the review included articles from the PubMed database, using the following search terms: DHEA, DHEA-S, T, memory, androgen deprivation therapy, tau protein, aging, and AD. Finally, we analyze the use of these steroids as an adjunct in the treatment of memory deficits in aging subjects and AD patients.

Age-related changes in the antidepressant-like effect of desipramine and fluoxetine in the rat forced-swim test.

Some reports suggest that older patients are less responsive to antidepressants than young adults, but this idea has not been fully supported. Here, we investigated the role of aging in the behavioral effects of the antidepressants, desipramine (DMI) (5, 10, and 20 mg/kg) and fluoxetine (FLX) (5, 10, and 20 mg/kg) in young adults (3-5 months), middle-aged (MA, 12-15 months), and senescent (SE, 23-25 months) male rats in the forced-swim test. In addition, locomotor activity and motor coordination were assessed as side-effects. DMI and fluoxetine produced an antidepressant-like effect in YA and MA animals, although in the latter group, a shift to the right in the dose-response curve was found for DMI. Importantly, neither drug was effective in SE animals. Motor side-effects were produced mainly by DMI in MA and SE rats. Therefore, a decrease in the antidepressant-like effect is associated strongly with senescence as well as an increased vulnerability to motor side-effects, particularly of tricyclics. This study is significant because SE animals are scarcely studied in pharmacological screening tests, and our findings might be useful for improving antidepressant treatments for the increasing aged population.

Age differences in the impact of forced swimming test on serotonin transporter levels in lateral septum and dorsal raphe.

BACKGROUND: Forced swimming test (FST) is an animal model which evaluates behavioral despair and the effect of antidepressants such as the selective serotonin reuptake inhibitors; the FST modifies the expression of some receptors related to antidepressant response, but it is not known whether serotonin transporter (SERT), their main target, is affected by this test in animals of different ages. Antidepressant response has shown age-dependent variations which could be associated with SERT expression. The aim of the present study was to analyze changes in the SERT immunoreactivity (SERT-IR) in dorsal raphe and lateral septum of male rats from different age groups with or without behavioral despair induced by their exposure to the FST, since these two structures are related to the expression of this behavior. METHODS: Prepubertal (24 PN), pubertal (40 PN), young adult (3-5 months) and middle-aged (12 months) male rats were assigned to a control group (non-FST) or depressed group (FST, two sessions separated by 24 h). Changes in SERT-IR in dorsal raphe and lateral septum were determined with immunofluorescence. RESULTS: Pubertal and middle-aged rats showed higher levels of immobility behavior compared to prepubertal rats on the FST. SERT-IR showed an age-dependent increase followed by a moderate decrease in middle-aged rats in both structures; a decreased in SERT-IR in lateral septum and dorsal raphe of pubertal rats was observed after the FST. CONCLUSIONS: Age differences were observed in the SERT-IR of structures related to behavioral despair; SERT expression was modified by the FST in lateral septum and dorsal raphe of pubertal rats.

Effects of housing condition on the development and persistence of addictive-like behavior induced by toluene.

Environmental factors can modify addictive responses induced by drugs of abuse; however, little is known about the impact of environmental conditions on behavioral responses induced by inhalants. In this study, we analyzed the effects of housing conditions, considering environmental enrichment (EE; n = 10), social isolation (SI; n = 10), and standard housing (STD; n = 10), as positive, negative, and control environments, respectively, on the development and persistence of behavioral sensitization induced by toluene. Mice exposed to air were used as a comparative control groups for each housing condition (EE: n = 11, SI: n = 10 and STD: n = 11). Results showed that a history of toluene exposure induced the development of locomotor sensitization in mice, independent of their housing conditions. However, SI increased the expression of behavioral sensitization to toluene after a drug-free period.

Developmental programming-ageing effects in muscle strength of obese rat offspring in a sex-dependent manner.

Maternal obesity programs the offspring to metabolic dysfunction. However, the effects of maternal obesity on skeletal muscle programming and ageing have been little explored. To determine if maternal obesity is a detriment to the progress of age-related muscle strength loss in the offspring (F1), we evaluated the indicators of muscle strength, adiposity, and metabolism at young adult and senior adult ages of maternal obesity F1 (MOF1) males and females from a high-fat diet-induced maternal obesity model in rat. Controls were agematched siblings whose mothers were fed a standard maternal diet (CF1). Combinatorial data analysis was performed with body weight (BW), forelimb grip strength (FGS), FGS adjusted with BW, body fat, adiposity index, and serum triacylglycerols, cholesterol, glucose, insulin, and homeostatic model assessment for insulin resistance variables, to identify discriminant traits of variation among F1 groups. During ageing, maternal obesity caused glucose and cholesterol metabolic dysfunctions in male F1, whereas adiposity-associated skeletal strength loss and fatty acid alterations were present in female offspring. In conclusion, offspring programming-ageing effects due to maternal obesity impact metabolism and skeletal muscle strength loss at later ages in a sex-dependent manner.

Testosterone prevents but not reverses anhedonia in middle-aged males and lacks an effect on stress vulnerability in young adults.

Middle-aged male rats are more vulnerable than young adult ones to develop anhedonia when exposed to chronic mild stress (CMS). Clinical studies support the idea that in aged subjects the low testosterone (T) levels are related with their higher stress vulnerability and that this hormone possesses antidepressant-like actions. In this study we evaluated the role of gonadal hormones--mainly T--on the depressive-like behavior of middle-aged and young adult male rats submitted to CMS. In middle-aged rats we analyzed the effect of T restitution (at the levels of young adult animals) given 3 weeks before (experiment 1) or 3 weeks after (experiment 2) anhedonia development (indicated by a reduction in sucrose solution intake). T restitution before CMS effectively prevented anhedonia but failed to reverse it once installed. In young adult rats we studied if orchidectomy increased stress vulnerability and found that it failed to modify sucrose intake. These results indicate a stress-dependent differential effect of T in middle-aged rats an age differential role of gonadal hormones on the vulnerability to develop anhedonia. The results suggest that T is a resilience factor in middle-aged but not in young adult males.

Effects of Palmitoylethanolamide (PEA) on Nociceptive, Musculoskeletal and Neuropathic Pain: Systematic Review and Meta-Analysis of Clinical Evidence.

Some 30−50% of the global population and almost 20% of the European population actually suffer from chronic pain, which presents a tremendous burden to society when this pain turns into a disability and hospitalization. Palmitoylethanolamide (PEA) has been demonstrated to improve pain in preclinical contexts, but an appraisal of clinical evidence is still lacking. The present study aimed at addressing the working hypothesis for the efficacy of PEA for nociceptive musculoskeletal and neuropathic pain in the clinical setting. The systematic search, selection and analysis were performed in agreement with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 recommendations. The primary outcome was pain reduction, as measured by a pain assessment scale. The secondary outcome was improvement in quality of life and/or of parameters of function. The results obtained for a total of 933 patients demonstrate the efficacy of PEA over the control (p < 0.00001), in particular in six studies apart from the two randomized, double-blind clinical trials included. However, the results are downgraded due to the high heterogeneity of the studies (I2 = 99%), and the funnel plot suggests publication bias. Efficacy in achieving a reduction in the need for rescue medications and improvement in functioning, neuropathic symptoms and quality of life are reported. Therefore, adequately powered randomized, double-blind clinical trials are needed to deepen the domains of efficacy of add-on therapy with PEA for chronic pain. PROSPERO registration: CRD42022314395.

GABA A /Benzodiazepine Receptor Complex in the Dorsal Hippocampus Mediates the Effects of Chrysin on Anxiety-Like Behaviour in Female Rats.

Systemic injections of the flavonoid chrysin (5,7-dihydroxyflavone) exert anxiolytic-like effects in ovariectomised and cycling female rats through actions on gamma-aminobutyric acid-A (GABA A ) receptors; however, it is unknown if chrysin directly acts on brain structures that are involved in regulating emotional processes, such as the hippocampus. The present study evaluated the effects of intrahippocampal microinjections of 0.25, 0.5, and 1 µg of chrysin on anxiety-like behaviour in the elevated plus maze (EPM) and locomotor activity test (LAT) in female rats in proestrus and dioestrus. Similar doses of the neurosteroid allopregnanolone were used as a reference GABAergic anxiolytic drug. The participation of the GABA A /benzodiazepine receptor complex was evaluated by administering the antagonists picrotoxin, bicuculline and flumazenil. In proestrus, 0.5 and 1 µg of chrysin and allopregnanolone induced anxiogenic-like behaviour. In dioestrus, chrysin, and allopregnanolone (0.5 µg) induced anxiolytic-like effects. Picrotoxin, bicuculline and flumazenil prevented the effects of chrysin and allopregnanolone in both proestrus and dioestrus. None of the treatments significantly affected locomotor activity. These results indicate that the GABA A /benzodiazepine receptor complex in the dorsal hippocampus regulates the effects of chrysin on anxiety-like behaviour, similar to the actions of allopregnanolone. The divergent effects of treatments across the oestrous cycle phases suggest complex interactions between GABA A receptors and compounds with an anxiolytic potential.

Antidepressant-like effects of acupuncture via modulation of corticosterone, sex hormones, and hippocampal BDNF expression in male rats.

BACKGROUND: Post-weaning social isolated rodents exhibit pathophysiological changes associated with depression including adrenal axis hyperactivity, gonadal hormone level disturbances, molecular alterations in hippocampus, and immobility behavior in the forced swimming test (FST). Although acupuncture by absorbable thread implantation (acu-catgut, AC) elicits antidepressant-like effects in social isolated rats, AC effects on neuroendocrine and hippocampal molecular alterations have been less characterized. OBJECTIVE: To investigate the participation of gonadal hormones, corticosterone, and brain-derived neurotrophic factor (BDNF) hippocampal expression, on the AC antidepressant-like effects in social isolated male rats. METHODS: Sprague-Dawley male rats were raised in social isolation (SI) or standard conditions, for 11 weeks. AC (on Baihui (Du20), Yintang (E X-HN3), Shenshu (BL 23), Pishu (BL 20), Ganshu (BL 18), Xinshu (BL 15) and Guanyuan (Ren 4)), or Sham-AC (puncturing of acupoints without embedding the thread), was applied during the last three weeks of isolation period. Rats were evaluated in the FST; hormones plasmatic levels and hippocampal BDNF content were quantified by ELISA and Western blotting, respectively. RESULTS: Social isolated rats showed more immobility in the FST and had lower testosterone and estradiol levels, higher corticosterone levels, and reduced hippocampal BDNF content than controls. BDNF level in hippocampus inversely correlated to depression-like behavior. AC but not sham-AC normalized immobility behavior, steroid hormone levels, and BDNF content, as in rats raised in a social environment. CONCLUSIONS: AC antidepressant effect could be related to an improvement of hippocampal BDNF protein expression, as well as corticosterone and sex hormones disturbances associated with prolonged exposure to stress caused by social isolation. Present findings have implications for depression treatment in individuals early exposed to stress.

Calea zacatechichi Schltdl. (Compositae) produces anxiolytic- and antidepressant-like effects, and increases the hippocampal activity during REM sleep in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Calea zacatechichi is a plant with an extensive popular and ritual use in Mexico. In healthy volunteers, it induces well-being and tranquility senses, and facilitates superficial stages of sleep. However, anxiolytic, and antidepressant-like effects and changes on the sleep-waking stages have not been explored. AIM: To determine anxiolytic and antidepressant-like effects of an aqueous extract of C. zacatechichi (CZ) in rodents and to analyze their effects on hippocampal activity in the rat sleep-waking cycle. MATERIAL AND METHODS: CZ anxiolytic- and antidepressant-like effects were evaluated in several mice and rat behavioral paradigms. CZ effects on temporal distribution of sleep were described, and hippocampus EEG frequency patterns were analyzed during the sleep-waking cycle; absolute and relative powers were analyzed during Rapid Eye Movements (REM) and non-REM sleep stages. CZ chemical analysis was performed by UPLC-ESI-MS. RESULTS: CZ produced specific and robust anxiolytic- and antidepressant-like effects in mice and rats, similar to those of prototypical drugs, at doses ranging from 0.5 to 50 mg/kg. CZ at 100 mg/kg produced visible mild sedative effects in rats, associated with a significant increase in Slow Wave Sleep episodes during a 6 h recording, and enhanced fast frequencies of hippocampus (gamma-band:31-50 Hz) during REM sleep. CONCLUSION: Results could support the well-being and tranquility senses reported by healthy consumers, and to explain the oneiric content during dreams and some improvements in cognitive processes described by consumers. Anxiolytic- and antidepressant-like effects of this species, reported for first time in this study could improve some aspects of mental health.

Role of Estradiol in the Expression of Genes Involved in Serotonin Neurotransmission: Implications for Female Depression.

BACKGROUND: In women, changes in estrogen levels may increase the incidence and/or symptomatology of depression and affect the response to antidepressant treatments. Estrogen therapy in females may provide some mood benefits as a single treatment or might augment clinical response to antidepressants that inhibit serotonin reuptake. OBJECTIVE: We analyzed the mechanisms of estradiol action involved in the regulation of gene expression that modulates serotonin neurotransmission implicated in depression. METHOD: Publications were identified by a literature search on PubMed. RESULTS: The participation of estradiol in depression may include regulation of the expression of tryptophan hydroxylase-2, monoamine oxidase A and B, serotonin transporter and serotonin-1A receptor. This effect is mediated by estradiol binding to intracellular estrogen receptor that interacts with estrogen response elements in the promoter sequences of tryptophan hydroxylase-2, serotonin transporter and monoamine oxidase-B. In addition to directly binding deoxyribonucleic acid, estrogen receptor can tether to other transcription factors, including activator protein 1, specificity protein 1, CCAAT/enhancer binding protein ß and nuclear factor kappa B to regulate gene promoters that lack estrogen response elements, such as monoamine oxidase-A and serotonin 1A receptor. CONCLUSION: Estradiol increases tryptophan hydroxylase-2 and serotonin transporter expression and decreases the expression of serotonin 1A receptor and monoamine oxidase A and B through the interaction with its intracellular receptors. The understanding of molecular mechanisms of estradiol regulation on the protein expression that modulates serotonin neurotransmission will be helpful for the development of new and more effective treatment for women with depression.

Piper auritum Kunth (Piperaceae) improves the sexual performance of sluggish male rats through enhancing ejaculation.

ETHNOPHARMACOLOGICAL RELEVANCE: Piper auritum Kunth is employed as an aphrodisiac in the traditional medicine, but corroborative evidence for such effect is scarce. AIM OF THE STUDY: The pro-sexual effect of an aqueous extract of P. auritum and its possible mechanisms were analyzed in two paradigms of male sexual function. MATERIAL AND METHODS: Effects of an aqueous extract of P. auritum (PA, single administration) were investigated in the fictive ejaculation, and copulatory behavior paradigms in sexually sluggish male rats. WAY 100635 (antagonist of 5-HT1A receptors), atosiban (antagonist of oxytocinergic receptors), L-NAME (inhibitor of the nitric oxide synthase) and baclofen (antagonist of GABAB receptors) were used as pre-treatments in order to investigate the role of different neurotransmitter systems in PA actions. Chemical profile of PA was determined by Gases Chromatography and Ultra Performance Chromatography-Electrospray Ionization-Masses Spectrometry (UPLC-ESI-MS). RESULTS: In males with retarded ejaculation, PA stimulated ejaculatory behavior and recovered electromyographic activity of pelvic musculature participating in seminal emission and ejaculation. All pre-treatments blocked stimulating effects of PA on the fictive ejaculation; additionally WAY 100635 interfered with PA actions on ejaculatory behavior. Safrol, apigenin dimethylether, myristicin, vaccihein A, sakuranin and sakuranetin flavonoids, were main constituents of PA, with possible participation in its pro-sexual effects. CONCLUSIONS: Pro-sexual effects of P. auritum elicited at level of ejaculation were mediated by several neurotransmitter systems, among which serotonin and its 5-HT1A receptors play an important role. Present findings support P. auritum reputation as an aphrodisiac, with potential use in delayed ejaculation disorder.

Estrogens participate in the antidepressant-like effect of desipramine and fluoxetine in male rats.

In male rats, the antidepressant-like effect of fluoxetine (FLX) and desipramine (DMI) in the forced swimming test (FST) is reduced by orchidectomy and partially restored by testosterone (T). It is unknown if this modulation of T is produced by its estrogenic metabolites. The objectives of this study were to evaluate if the aromatase inhibitor, formestane, interferes with the antidepressant-like effect of DMI and FLX in intact male rats, and to analyze if 17beta-estradiol (E2) modifies the FST and interacts with the antidepressants in orchidectomized (Orx) males. Intact males received DMI (1.25-5.0 mg/kg) and FLX (2.5-10 mg/kg) alone or in combination with formestane (17.5 mg/kg). Orx rats received E2 (5, 10, 20 and 40 microg/rat) or the combination of E2 [at sub-threshold (5 microg/rat) and optimal (10 microg/rat) doses] plus sub-effective doses of DMI (2.5 mg/kg) or FLX (10 mg/kg). Serum testosterone and estradiol levels were measured in intact-control and -formestane treated animals as well as in castrated males replaced with various doses of E2. Formestane in intact males lacked of an action in the FST, but cancelled the antidepressant-like effect of DMI and FLX. E2 at the supra-physiological doses of 10 and 20 microg/rat produced antidepressant-like effects. E2 at 5 microg/rat (that re-established the levels of this hormone to physiological levels) and at 10 microg/rat restored the antidepressant-like action of DMI and FLX in Orx rats. It was concluded that estrogens participate in the antidepressant-like effect of DMI and FLX in the FST.

Forced ethanol ingestion by Wistar rats from a juvenile age increased voluntary alcohol consumption in adulthood, with the involvement of orexin-A.

Human adolescents who drink alcohol are more likely to become alcoholics in adulthood. Alcohol administration (intraperitoneally) or drinking (in a 2-bottle free choice paradigm) during the juvenile/adolescent age of rats promotes voluntary alcohol consumption in adulthood. On the other hand, there is growing evidence that the orexinergic system plays a role in several rewarded behaviors, including alcohol ingestion. Since it is unknown what effect is exerted in adulthood by forced oral ethanol intake and/or administration of orexin-A (OX-A) in juvenile rats, the present study aimed to evaluate this question. A group of male Wistar rats was forced to drink ethanol (10% v/v) as the only liquid in the diet from weaning (postnatal day 21) to postnatal day 67 (46 days), followed by a forced withdrawal period. An age-matched group was raised drinking tap water (control). OX-A or its vehicle was microinjected intracerebroventricularly (i.c.v.) (1 nmol/0.6 µL) to explore its effect as well. Locomotor activity and voluntary ethanol consumption were later assessed in all groups. The rats forced to consume ethanol early in life showed an elevated level of ambulation and alcohol ingestion in adulthood. A single injection of OX-A increased locomotor activity and acute ethanol intake in rats with or without prior exposure to alcohol at the juvenile stage. In conclusion, forced ethanol consumption in juvenile rats led to increased voluntary alcohol drinking behavior during adulthood, an effect likely facilitated by OX-A.

Antidepressant effects of acupoint stimulation and fluoxetine by increasing dendritic arborization and spine density in CA1 hippocampal neurons of socially isolated rats.

Given the importance of depression and the adverse effects of conventional treatment, it is necessary to seek complementary therapies. In a rat model of depression, this study aimed to assess the behavioral and morphological effects of embedding absorbable thread in acupoints (acu-catgut), and compare the results to those of fluoxetine treatment and the corresponding control groups. Therefore, depressive-like behavior was evaluated with the forced swimming test, and dendritic morphology (in the CA1 hippocampal region) with the Golgi-Cox technique and Sholl analysis. After weaning, male Sprague-Dawley rats were housed in social isolation for 8 weeks to induce depressive-like behavior. They were then given a 21-day treatment by stimulating acupoints with acu-catgut (AC) or fluoxetine (FX) (2 mg/kg). Rats were divided into six groups: Control (socially housed), social isolation (SI), SI + AC, SI + Sham (sham embedding of thread), SI + FX and SI + VH (vehicle). Compared to fluoxetine, acu-catgut treatment was more effective in reversing depressive-like behavior elicited by SI. The SI-induced reduction in dendritic length and spine density in hippocampal CA1 pyramidal neurons was attenuated after prolonged treatment with acu-catgut or fluoxetine. Hence, both treatments proved capable of reversing depressive-like alterations caused by SI, likely due to dendritic remodeling in the hippocampus.