Effects of the designer drug 4-methylamphetamine on core temperature and serotonin levels in the striatum and hippocampus of rats.

New psychoactive substances (NPS) are typically synthesized in clandestine laboratories in an attempt to chemically modify already federally regulated drugs in an effort to circumvent the law. Drugs derived from a phenethylamine pharmacophore, such as 4-chloroamphetamine and 3,4-methylenedioxymethamphetamine (MDMA), reliably induce thermogenesis and serotonergic deficits in the striatum and hippocampus of rodents. 4-methylamphetamine (4-MA), a relative newcomer to the NPS scene, was originally investigated in the mid-1900 s as a potential anorexigenic agent. With its phenethylamine pharmacophore, 4-MA was hypothesized to produce similar toxicological alterations as its chemical analogs. In the present study, three doses (1.0, 2.5, and 5.0 mg/kg, ip.) of 4-MA were administered to rats twice daily for two days. Core temperature data were calculated and analyzed as temperature area under the curve (TAUC). On the second day of dosing, a hypothermic response to 4-MA (2.5 and 5.0 mg/kg) was noted between 0.5 and 2.0 h post-treatment. Only the highest dose of 4-MA decreased body weight on the second day of treatment and maintained this reduction in weight for seven days after treatment ceased. None of the doses of 4-MA evaluated significantly altered serotonin levels in the hippocampus or striatum seven days after final treatment. The present findings demonstrate that the 4-methyl substitution to amphetamine generates a pharmacological and toxicological profile that differs from other similar phenethylamine analogs.

Determination of flibanserin in the presence of confirmed degradation products by a third derivative emission spectrofluorometric method: Application to pharmaceutical formulation.

Flibanserin is a new drug used for the treatment of hypoactive sexual desire disorder. This work is considered the first study concerning the fluorimetric behaviour of flibanserin and its new florescent degradation products. A fast, cost-effective, stability-indicating spectrofluorometric method was developed and validated for the determination of flibanserin in the presence of oxidative degradation products. Stability studies are performed to predict the behaviour of substances under various harsh conditions. Thus, flibanserin was subjected to degradation using hydrogen peroxide. The stability-indicating method was developed and validated per ICH guidelines; it was linear in the range of 0.1-3 µg/mL. The method was accurate and precise as it showed good recoveries between 98.50 and 100.90% and relative standard deviation less than 2%, respectively, and no significant differences were found after statistical comparison with the in-house HPLC method. In addition, the structures of the oxidative degradation products were confirmed using infrared spectroscopy and mass spectrometry, and the proposed degradation pathway was predicted.

Receptores sigma1: um novo alvo para o tratamento farmacológico da depressão? / A new target for the pharmacologycal treatment of depression?

Apesar de décadas de estudos sobre os antidepressivos (ADs), seus mecanismos de ação permanecem obscuros. Muitos ADs interagem com receptores sigma e evidências crescentes sugerem que estas proteínas medeiam efeitos antidepressivos em animais e humanos. Os receptores sigma são subdivididos em dois subtipos, sigma-1 e sigma-2. Em particular, uma potencial atividade antidepressiva foi postulada para agonistas do receptor sigma-1, os quais se localizam predominantemente no reticulo- endoplasmático de neurônios e oligodendrócitos. Os receptores sigma estão localizados em regiões cerebrais que são afetadas na depressão e são capazes de modular a atividade dos sistemas centrais de neurotransmissores, incluindo os sistemas noradrenérgico, serotonérgico, dopaminérgico e glutamatérgico (NMDA), que são considerados importantes no mecanismo de ação dos ADs conhecidos. O foco desta revisão é discutir a literatura relacionada aos receptores sigma e aos seus ligantes em relação às suas propriedades antidepressivas.

Envolvimento da neurotransmissão serotoninérgica no efeito antiimobilidade da Kielmeyera coriacea-Clusiaceae-Martius em ratos / Envolvement of the serotoninergic neurotransmission in the effect antiimmobility of the Kielmeyera coriacea-Clusiaceae-Martius in rats

Devido à similaridade botânica taxonômica e química entre Hypericum perforatum, que é efetivo no tratamento de depressão leve a moderada, e Kielmeyera coriacea, o perfil farmacológico do extrato hidroetanólico (EH) de caule de Kielmeyera coriacea foi investigado, utilizando-se o modelo animal do nado forçado (TNF), um teste indicativo de atividade antidepressiva. O tempo de imobilidade no TNF foi significativamente reduzido pela administração por gavage, em ratos, de 60 mg/Kg do extrato, sem aumentar a atividade locomotora no teste do campo aberto (TCA), sugerindo perfil de composto antidepressivo específico. A eficácia do HE de caule de Kielmeyera coriacea foi comparada aos antidepressivos, nortriptilina (15 mg/Kg) e fluoxetina (10 mg/Kg), também administrados por gavage. O efeito antiimobilidade do extrato analisado no TNF foi revertido pela administração direta, no núcleo dorsal da rafe (NDR) de ratos, de serotonina (5-HT), R(+)-8-hidroxi-2-(di-n-propilamino)tetralina (8-OHDPAT), um agonista de receptores 5-HT1A e metergolina, um antagonista não seletivo de receptores serotoninérgicos. Testes bioquímicos mostraram que o EH de Kielmeyera coriacea inibiu de maneira concentração dependente a captação sinaptossomal de 5-HT, noradrenalina (NA) e dopamina (DA). A concentração inibitória média mostrou que o extrato foi mais potente em inibir captação de 5-HT. Testes preliminares de toxicidade mostraram que durante o período de administração de 45 dias, o EH de Kielmeyera coriacea não produziu mortalidade nem alterações na evolução ponderal, no peso dos órgãos vitais dos animais testados, quando comparados ao controle. A dose letal média (DL50) não foi atingida em camundongos até a dose de 1200 mg/Kg do extrato vegetal. Estes resultados em conjunto mostram um perfil de composto antidepressivo para o EH de Kielmeyera coriacea e sugerem que a neurotransmissão serotoninérgica esteja envolvida em seu efeito antiimobilidade observado em ratos no TNF. A inibição de reca...

Multiple 5-HT receptors are involved in the effects of acute MDMA treatment: studies on locomotor activity and responding for conditioned reinforcement.

RATIONALE: Responding for conditioned reinforcement is increased by the dopamine releasing agent amphetamine, but reduced by drugs that enhance serotonin (5-HT) function. The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) releases both monoamines. OBJECTIVES: The primary purpose of this study was to examine the effects of MDMA on responding for conditioned reinforcement as well as on locomotor activity. The roles of several 5-HT receptor sub-types in mediating these behavioural effects of MDMA were also examined. METHODS: Locomotion was measured in photocell activity monitors. For conditioned reinforcement experiments thirsty rats learned to associate a conditioned stimulus (CS) with water in operant chambers. Subsequently, two response levers were available; responding on one lever delivered the CS, while responding on the second lever had no consequences. Drug effects on this operant response were measured. RESULTS: MDMA dose-dependently increased locomotion but reduced responding for conditioned reinforcement. This latter effect differs from that induced by amphetamine, which potentiates conditioned reinforcement responding. The stimulant effect of MDMA was attenuated by GR127935 and ketanserin, indicating facilitatory roles of 5-HT(1B) and 5-HT(2A) receptors in mediating this effect. The 5-HT(2C) antagonist SB242084 enhanced the stimulant effect of MDMA. Only SB242084 attenuated the suppressant effect of MDMA on responding for conditioned reinforcement. CONCLUSIONS: The results show that 5-HT(2A) and 5-HT(1B/1D) receptors play a facilitatory role in mediating the stimulant effect of MDMA, whereas 5-HT(2C) receptors are inhibitory. Activation of 5-HT(2C) receptors also contributes to the deficit in operant responding. Multiple 5-HT receptor sub-types appear to contribute to the behavioural effects of MDMA.

Serotonin-containing fibers in the suprachiasmatic hypothalamus attenuate light-induced phase delays in mice.

Photic and non-photic stimuli phase shift and entrain circadian rhythms through distinct but interacting mechanisms which impinge on the suprachiasmatic nucleus (SCN), the circadian pacemaker. Our understanding of this mechanism is incomplete. Serotonin (5-HT) injected locally at the SCN reduces light-induced glutamate release and decreases the expression of c-fos, a marker of photic transduction. Furthermore, in SCN slices, 5-HT application reduces field potentials after optic nerve stimulation. We therefore predicted that 5-HT-terminal destruction restricted to the SCN would augment phase shifts of circadian rhythms induced by light exposure. To investigate this possibility, we compared photic phase delays and Fos-like immunoreactivity in mice which had previously received bilateral infusions directed at the SCN containing either the selective 5-HT neurotoxin 5,7-dihydroxytryptamine (DHT, n = 16) or vehicle (VEH, n = 12). Phase delays after a light pulse given during the mid-subjective night (30 lux, 30 min starting at circadian time (CT) 12-20) in DHT-mice were 50% greater than in VEH-mice (P = 0.017). DHT mice (n = 5) had 76% larger Fos responses to a mid-subjective night light pulse than VEH-mice (n = 5) (P = 0.029). We conclude that 5-HT at or near the SCN in mice reduces photic phase shifts and modulates the magnitude of the photic phase response in the mouse.

Analysis of non-benzodiazepinic anxiolytic agents by capillary zone electrophoresis.

A simple capillary electrophoretic method was developed for the analysis of a new generation of serotonergic anxiolytics and their related substances: zalospirone, gepirone, ipsapirone and buspirone. All compounds run in a Tris/phosphate buffer at pH 3 as cations and the experimental conditions allowed good resolution of four drugs and their principal impurities. The analyses were made using two different kinds of capillary. The suitability of CZE and HPLC methods for the analysis of these non-benzodiazepinic anxiolytic agents and their impurities was compared.