Tamoxifen antagonizes the effects of ovarian hormones to induce anxiety and depression-like behavior in rats / Tamoxifeno antagoniza os efeitos dos hormônios ovarianos que induzem comportamento similar a ansiedade e depressão em ratos

The effects of tamoxifen (TAM) on anxiety and depression-like behavior in ovariectomized (OVX) and naïve female rats were investigated. The animals were divided into Sham-TAM, OVX-TAM, Sham and OVX groups. Tamoxifen (1 mg/kg) was administered for 4 weeks. In the forced swimming test, the immobility times in the OVX and Sham-TAM groups were higher than in the Sham group. In the open field, the numbers of central crossings in the OVX and Sham-TAM groups were lower than the number in the Sham group, and the number of peripheral crossings in the OVX group was lower than the number in the Sham group. In the elevated plus maze, the numbers of entries to the open arm among the animals in the Sham-TAM and OVX groups were lower than the number in the Sham group, while the number of entries to the open arm in the OVX-TAM group was higher than the number in the OVX group. It was shown that deletion of ovarian hormones induced anxiety and depression-like behavior. Administration of tamoxifen in naïve rats led to anxiety and depression-like behavior that was comparable with the effects of ovarian hormone deletion. It can be suggested that tamoxifen antagonizes the effects of ovarian hormones. It also seems that tamoxifen has anxiolytic effects on ovariectomized rats.

Foram investigados os efeitos do tamoxifeno (TAM) no comportamento semelhante a ansiedade de depressão de ratas ooforectomizadas (OVX) e controles. Os animais foram divididos em Sham-TAM, OVX-TAM, Sham e OVX groups. Tamoxifeno (1 mg/kg) foi administrado por quatro semanas. No teste de natação forçada, os tempos de imobilidade nos grupos OVX e Sham-TAM foram maiores que aqueles do grupo Sham. No campo aberto, os números de cruzamento no centro nos grupos OVX e Sham-TAM foram menores que aquele do grupo Sham, e o número dos cruzamentos na periferia no grupo OVX foi menor que o número no grupo Sham. No labirinto elevado, os números de entradas com braços abertos entre os animais nos grupos Sham-TAM e OVX foram menores do que aqueles do grupo Sham, enquanto o número de entradas com os braços abertos no grupo OVX-TAM foi maior que aquele no grupo OVX. Foi observado que a deleção dos hormônios ovarianos induziu comportamento similar a ansiedade e depressão. A administração de tamoxifeno em ratos controle induziu a um comportamento que era comparável aos efeitos da deleção do hormônio ovariano. Pode ser sugerido que o tamoxifeno antagoniza os efeitos dos hormônios ovarianos. Parece também que o tamoxifeno tem efeito ansiolítico nas ratas ooforectomizadas.

Histone deacetylase activity and brain-derived neurotrophic factor (BDNF) levels in a pharmacological model of mania

Objective: In the present study, we aimed to examine the effects of repeated D-amphetamine (AMPH) exposure, a well-accepted animal model of acute mania in bipolar disorder (BD), and histone deacetylase (HDAC) inhibitors on locomotor behavior and HDAC activity in the prefrontal cortex (PFC) and peripheral blood mononuclear cells (PBMCs) of rats. Moreover, we aimed to assess brain-derived neurotrophic factor (BDNF) protein and mRNA levels in these samples. Methods: We treated adult male Wistar rats with 2 mg/kg AMPH or saline intraperitoneally for 14 days. Between the 8th and 14th days, rats also received 47.5 mg/kg lithium (Li), 200 mg/kg sodium valproate (VPT), 2 mg/kg sodium butyrate (SB), or saline. We evaluated locomotor activity in the open-field task and assessed HDAC activity in the PFC and PBMCs, and BDNF levels in the PFC and plasma. Results: AMPH significantly increased locomotor activity, which was reversed by all drugs. This hyperactivity was associated with increased HDAC activity in the PFC, which was partially reversed by Li, VPT, and SB. No differences were found in BDNF levels. Conclusion: Repeated AMPH administration increases HDAC activity in the PFC without altering BDNF levels. The partial reversal of HDAC increase by Li, VPT, and SB may account for their ability to reverse AMPH-induced hyperactivity. .

Cambios en la hemodinamia cerebral en consumidores crónicos de paco y cocaína: estudio de casos y controles / [Changes in cerebral hemodynamics in chronic users of \"PACO\" and cocaine: case-control study].

OBJECTIVE: To assess if there are changes in brain hemodynamics evaluated by means of transcranial doppler’s flow velocity, pulsatile index and cerebral perfusion pressure, between cocaine chronic abusers and healthy volunteers. METHOD: Prospective, case and control, observational study. Sex, age, user history, vital signs and transcranial doppler findings.Statistical analysis was performed by means of normality test, Wilcoxon’s test for non parametric samples and T Student test. RESULTS: Fifty-three abusers and 35 healthy volunteers were studied. Statistical differences were found for a diminish in age(p=0.008) and cerebral perfusion pressure in all cerebral arteries (p

Effects of fluoxetine and imipramine in rat fetuses treated during a critical gestational period: a macro and microscopic study / Efeitos da fluoxetina e imipramina em fetos de ratas tratadas durante o período crítico da gestação: estudo macro e microscópico

OBJECTIVE: To evaluate morphological alterations in rat fetuses treated with fluoxetine and imipramine during the "critical" period of gestation. METHOD: Fifteen female rats were separated into three groups (n = 5) and treated with 10 mg/kg/day of test substances on the ninth, tenth and eleventh day of pregnancy: G1, fluoxetine; G2, imipramine hydrochloride; G3 (control), saline. On day 21, cesarean sections were performed to release the fetuses, whose bodies were weighed and macroscopically analyzed. The placenta was also weighed. The fetuses were then fixed and their encephala removed and weighed. Sections of the frontal lobe were taken for histological neuron counting. RESULTS: G1 and G2 showed the highest fetal body weight. Placental weight showed statistical differences (p < 0.01): G1 weighed more than G2 and G3. Otherwise, G2 exhibited the highest encephalon weight, statistically differing from G3 (control) and fluoxetine-treated G1 (p < 0.01). However, G1 did not statistically (p > 0.01) differ from the control group. G3 showed the highest number of neurons per area when compared to G1 and G2 (p < 0.01). CONCLUSION: The use of antidepressants in rats caused an increase in fetal weight and a decrease in the number of fetal frontal lobe neurons, thus suggesting that the use of antidepressants by pregnant women can induce depression in fetuses due to alterations in their neural development.

OBJETIVO: Avaliar as possíveis alterações ocorridas em nível macroscópico e microscópico de fetos de ratas submetidas ao tratamento com fluoxetina e imipramina durante o período "crítico" da gestação. MÉTODO: Quinze ratas, posteriormente ao acasalamento, foram divididas em três grupos experimentais (n = 5): G1, tratadas com 10mg/kg/dia de fluoxetina; G2, tratadas com 10mg/kg/dia de cloridrato de imipramina, e G3 (controle), tratadas com 10mg/kg/dia de solução fisiológica a 0,9 por cento, no 9º, 10º e 11º dias de prenhez das ratas. Posteriormente à cesária, no 21º dia de prenhez, analisou-se macroscopicamente o peso fetal e placentário. Os fetos foram fixados e houve a remoção do encéfalo para pesagem e preparação das lâminas do tecido neuronal para contagem de neurônios do lobo frontal. RESULTADOS: O G1 e G2 apresentaram maior peso fetal. O G1 apresentou maior peso placentário, diferindo do G2 e G3 (p < 0,01). De forma diferente, o G2 possuiu maior peso encefálico, diferindo do G3 e G1 (p < 0,01). G1 não diferiu estatisticamente do grupo controle (p > 0,01). O G3 exibiu maior número de neurônios, por área, do lobo frontal em relação a G1 e G2 (p < 0,01). CONCLUSÃO: A adoção dos antidepressivos causou, nos fetos, aumento de peso e redução da contagem de neurônios do lobo frontal, sugerindo que a indicação de antidepressivos às gestantes pode induzir a depressão nos fetos por alterações em seu neurodesenvolvimento.

Effects of dextromethorphan on dopamine dependent behaviours in rats.

Dextromethorphan, a noncompetitive blocker of N-methyl-D- aspartate (NMDA) type of glutamate receptor, at 7.5-75 mg/kg, ip did not induce oral stereotypies or catalepsy and did not antagonize apomorphine stereotypy in rats. These results indicate that dextromethorphan at 7.5-75 mg/kg does not stimulate or block postsynaptic striatal D2 and D1 dopamine (DA) receptors. Pretreatment with 15 and 30 mg/kg dextromethorphan potentiated dexamphetamine stereotypy and antagonised haloperidol catalepsy. Pretreatment with 45, 60 and 75 mg/kg dextromethorphan, which release 5-hydroxytryptamine (5-HT), however, antagonised dexamphetamine stereotypy and potentiated haloperidol catalepsy. Apomorphine stereotypy was not potentiated or antagonised by pretreatment with 7.5-75 mg/kg dextromethorphan. This respectively indicates that at 7.5-75 mg/kg dextromethorphan does not exert facilitatory or inhibitory effect at or beyond the postsynaptic striatal D2 and D1 DA receptors. The results are explained on the basis of dextromethorphan (15-75 mg/kg)-induced blockade of NMDA receptors in striatum and substantia nigra pars compacta. Dextromethorphan at 15 and 30 mg/kg, by blocking NMDA receptors, activates nigrostriatal dopaminergic neurons and thereby potentiates dexampetamine stereotypy and antagonizes haloperidol catalepsy. Dextromethorphan at 45, 60 and 75 mg/kg, by blocking NMDA receptors, releases 5-HT and through the released 5-HT exerts an inhibitory influence on the nigrostriatal dopaminergic neurons with resultant antagonism of dexampetamine stereotypy and potentiation of haloperidol catalepsy.

Psicofarmacoterapia antidepresiva / Antidepressant pharmacotherapy

Considering the prevalence of major unipolar depression, the economical costs of its management and the different medications available for its treatment, it is imperative to have a good knowledge of the basic principles used to classify anti depressive medications. A good acquaintance on their mechanisms of action on neurotransmission and receptors, wil allow a better understanding of their therapeutic action and secondary effects. Tricyclics, non selective MAO inhibitors, reversible MAO inhibitors, selective serotonin reuptake inhibitors, dopamine and noradrenalin reuptake inhibitors, 5-HT2 blockers with serotonin reuptake blocking effect, serotonin, noradrenalin and dopamine reuptake inhibitors, alfa 2 receptor blockers and 5-HT/2-3 inhibitors are the eight available types of antidepressants