RESUMO
OBJECTIVE: The aim of this study was to examine the effectiveness of ramelteon and suvorexant for delirium prevention in real-world practice. It explored whether ramelteon and/or suvorexant would affect delirium prevention among both patients at risk for but without delirium (patients at risk) and those with delirium the night before a consultation. METHODS: This multicenter, prospective, observational study was conducted by trained psychiatrists at consultation-liaison psychiatric services from October 1, 2017, to October 7, 2018. Patients who were aged 65 years or older and hospitalized because of acute diseases or elective surgery, had risk factors for delirium, and had insomnia or delirium on the night before the consultation were prescribed ramelteon and/or suvorexant. The decision to take medication was left to the discretion of each patient. The primary outcome was incidence of delirium based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, during the first 7 days. RESULTS: Among 526 patients at risk, those taking ramelteon and/or suvorexant developed delirium significantly less frequently than those who did not, after control for the effects of risk factors on the estimate of an independent association between the effects of ramelteon and/or suvorexant and the outcome of developing delirium (15.7% vs 24.0%; odds ratio [OR] = 0.48;, 95% CI, 0.29-0.80; P = .005). Similar results were found among 422 patients with delirium (39.9% vs 66.3%; OR = 0.36; 95% CI, 0.22-0.59; P < .0001). CONCLUSIONS: Ramelteon and suvorexant appear to be effective for delirium prevention in real-world practice.
Assuntos
Azepinas/uso terapêutico , Delírio/prevenção & controle , Indenos/uso terapêutico , Medicamentos Indutores do Sono/uso terapêutico , Triazóis/uso terapêutico , Idoso , Delírio/etiologia , Feminino , Hospitalização , Humanos , Estimativa de Kaplan-Meier , Masculino , Estudos Prospectivos , Fatores de Risco , Resultado do TratamentoRESUMO
Equipment for the non-destructive evaluations of a tomato has been developed based on the scattering spectra, the angular distributions of the scattering intensities, and the scattering images from the specimens. The sugar concentrations of tomato can be estimated optically based on the scattering intensities using a halogen lamp, a white light-emitting diode (white LED), a yellow LED, a red LED, and near infrared LEDs (λ = 850 nm and 940 nm) as the incident lights. The scattering intensity is found to vary linearly with sugar concentrations of tomato with any wavelengths at which the scattering light can be observed. The gradient of calibration lines of the sugar concentrations against the scattering intensities varies with scattering angles, θ. Evaluations at around θ = 160° are found to be suitable because of the large gradient and good linearity with the correlation coefficient, R, close to 1.
Assuntos
Açúcares da Dieta/análise , Análise de Alimentos/métodos , Imagem Óptica/métodos , Solanum lycopersicum/química , Calibragem , Análise de Alimentos/instrumentação , Luz , Modelos Lineares , Imagem Óptica/instrumentação , Espalhamento de Radiação , Análise EspectralRESUMO
H2S has excitatory and inhibitory effects on Ca2+ signals via transient receptor potential ankyrin 1 (TRPA1) and ATP-sensitive K+ channels, respectively. H2S converts intracellularly to polysulfides, which are more potent agonists for TRPA1 than H2S. Under inflammatory conditions, changes in the expression and activity of these H2S target channels and/or the conversion of H2S to polysulfides may modulate H2S effects. Effects of proinflammatory cytokines on H2S-induced Ca2+ signals and polysulfide production in RIN14B cells were examined using fluorescence imaging with fura-2 and SSP4, respectively. Na2S, a H2S donor, induced 1) the inhibition of spontaneous Ca2+ signals, 2) inhibition followed by [Ca2+]i increase, and 3) rapid [Ca2+]i increase without inhibition in 50% (23/46), 22% (10/46), and 17% (8/46) of cells tested, respectively. IL-1ß augmented H2S-induced [Ca2+]i increases, which were inhibited by TRPA1 and voltage-dependent L-type Ca2+ channel blockers. However, IL-1ß treatment did not affect [Ca2+]i increases evoked by a TRPA1 agonist or high concentration of KCl. Na2S increased intracellular polysulfide levels, which were enhanced by IL-1ß treatment. A NOS inhibitor suppressed the increased polysulfide production and [Ca2+]i increase in IL-1ß-treated cells. These results suggest that IL-1ß augments H2S-induced [Ca2+]i increases via the conversion of H2S to polysulfides through NO synthesis, but not via changes in the activity and expression of target channels. Polysulfides may play an important role in the effects of H2S during inflammation.
Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Cálcio/metabolismo , Sulfeto de Hidrogênio/farmacologia , Interleucina-1beta/farmacologia , Óxido Nítrico/metabolismo , Sulfetos/metabolismo , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Células Cultivadas , Citocinas/farmacologia , Interações Medicamentosas , Óxido Nítrico Sintase/antagonistas & inibidores , Cloreto de Potássio/farmacologia , Ratos , Sulfetos/farmacologia , Canal de Cátion TRPA1/agonistas , Canal de Cátion TRPA1/antagonistas & inibidoresRESUMO
OBJECTIVE: No highly effective pharmacologic interventions to prevent delirium have been identified. We examined whether suvorexant, a potent and selective orexin receptor antagonist, is effective for the prevention of delirium. METHODS: We conducted a multicenter, rater-blinded, randomized, placebo-controlled clinical trial in intensive care units and regular acute wards between April 2015 and March 2016. Eligible patients were 65 to 89 years old, newly admitted due to emergency, and able to take medicine orally and had an expected stay or life expectancy of 48 hours or more. Seventy-two patients were randomly assigned using the sealed envelope method to receive suvorexant (15 mg/d; 36 patients) or placebo (36 patients) every night for 3 days. The primary outcome measure was incidence of delirium as determined by the DSM-5. Trained psychiatrists assessed for delirium. RESULTS: We found that delirium developed significantly less often among patients taking suvorexant than among those taking placebo (0% [n/N = 0/36] vs 17% [6/36], respectively, P = .025). Comparison by log-rank test also showed that delirium developed significantly less often among patients taking suvorexant than among those taking placebo (χ² = 6.46, P = .011). Analysis of variance revealed a tendency for main effect of treatment (F = 3.79, P = .053) on the sleep-wake cycle disturbance score (item 1) of the Japanese version of the Delirium Rating Scale-Revised-98 (DRS-R-98-J). There were no significant differences in adverse events. CONCLUSIONS: Suvorexant administered nightly to elderly patients admitted for acute care may provide protection against delirium. Larger studies are needed to show the potential of suvorexant to improve the circadian core domain of delirium. TRIAL REGISTRATION: UMIN Clinical Trials Registry identifier: UMIN000015681â.
Assuntos
Azepinas , Delírio , Triazóis , Idoso , Idoso de 80 Anos ou mais , Azepinas/administração & dosagem , Azepinas/efeitos adversos , Delírio/diagnóstico , Delírio/tratamento farmacológico , Delírio/prevenção & controle , Manual Diagnóstico e Estatístico de Transtornos Mentais , Método Duplo-Cego , Monitoramento de Medicamentos/métodos , Feminino , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Antagonistas dos Receptores de Orexina/administração & dosagem , Antagonistas dos Receptores de Orexina/efeitos adversos , Escalas de Graduação Psiquiátrica , Resultado do Tratamento , Triazóis/administração & dosagem , Triazóis/efeitos adversosRESUMO
Epithelioid cells in the chicken thoracic aorta are chemoreceptor cells that release 5-HT in response to hypoxia. It is likely that these cells play a role in chemoreception similar to that of glomus cells in the carotid bodies of mammals. Recently, H2S was reported to be a key mediator of carotid glomus cell responses to hypoxia. The aim of the present study was to reveal the mechanism of action of H2S on 5-HT outflow from chemoreceptor cells in the chicken thoracic aorta. The 5-HT outflow induced by NaHS, an H2S donor, and Na2S3, a polysulfide, was measured by using a HPLC equipped with an electrochemical detector. NaHS (0.3-3mM) caused a concentration-dependent increase in 5-HT outflow, which was significantly inhibited by the removal of extracellular Ca(2+). 5-HT outflow induced by NaHS (0.3mM) was also significantly inhibited by voltage-dependent L- and N-type Ca(2+) channel blockers and a selective TRPA1 channel blocker. Cinnamaldehyde, a TRPA1 agonist, mimicked the secretory response to H2S. 5-HT outflow induced by Na2S3 (10µM) was also inhibited by the TRPA1 channel blocker. Furthermore, the expression of TRPA1 was localized to 5-HT-containing chemoreceptor cells in the aortic wall. These findings suggest that the activation of TRPA1 and voltage-dependent Ca(2+) channels is involved in H2S-evoked 5-HT release from chemoreceptor cells in the chicken aorta.
Assuntos
Aorta Torácica/efeitos dos fármacos , Células Quimiorreceptoras/efeitos dos fármacos , Células Epitelioides/efeitos dos fármacos , Sulfeto de Hidrogênio/metabolismo , Serotonina/metabolismo , Sulfetos/farmacologia , Canais de Potencial de Receptor Transitório/efeitos dos fármacos , Animais , Aorta Torácica/metabolismo , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/efeitos dos fármacos , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo N/efeitos dos fármacos , Canais de Cálcio Tipo N/metabolismo , Células Quimiorreceptoras/metabolismo , Galinhas , Relação Dose-Resposta a Droga , Células Epitelioides/metabolismo , Técnicas In Vitro , Masculino , Transdução de Sinais/efeitos dos fármacos , Sulfetos/metabolismo , Canais de Potencial de Receptor Transitório/metabolismoRESUMO
Chemoreceptor cells aggregating in clusters in the chicken thoracic aorta contain 5-hydroxytryptamine (5-HT) and have voltage-dependent ion channels and nicotinic acetylcholine receptors, which are characteristics typically associated with neurons. The aim of the present study was to investigate the effects of 5-HT uptake inhibitors, fluvoxamine, fluoxetine and clomipramine (CLM), and amphetamine derivatives, p-chloroamphetamine (PCA) and methamphetamine (MET), on endogenous 5-HT outflow from the isolated chick thoracic aorta in vitro. 5-HT was measured by using a HPLC system with electrochemical detection. The amphetamine derivatives and 5-HT uptake inhibitors caused concentration-dependent increases in endogenous 5-HT outflow. PCA was about ten times more effective in eliciting 5-HT outflow than MET. The 5-HT uptake inhibitors examined had similar potency for 5-HT outflow. PCA and CLM increased 5-HT outflow in a temperature-dependent manner. The outflow of 5-HT induced by PCA or 5-HT uptake inhibitors was independent of extracellular Ca(2+) concentration. The 5-HT outflow induced by CLM, but not that by PCA, was dependent on the extracellular NaCl concentration. These results suggest that the 5-HT uptake system of 5-HT-containing chemoreceptor cells in the chicken thoracic aorta has characteristics similar to those of 5-HT-containing neurons in the mammalian central nervous system (CNS).
Assuntos
Aorta Torácica/efeitos dos fármacos , Metanfetamina/farmacologia , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Serotonina/metabolismo , p-Cloroanfetamina/farmacologia , Animais , Aorta Torácica/metabolismo , Galinhas , Clomipramina/farmacologia , Fluoxetina/farmacologia , Fluvoxamina/farmacologia , Técnicas In Vitro , MasculinoRESUMO
Hydrogen sulfide (H2S) reportedly acts as a gasotransmitter because it mediates various cellular responses through several ion channels including ATP-sensitive K(+) (KATP) channels and transient receptor potential (TRP) A1 channels. H2S can activate both KATP and TRPA1 channels at a similar concentration range. In a single cell expressing both channels, however, it remains unknown what happens when both channels are simultaneously activated by H2S. In this study, we examined the effects of H2S on RIN14B cells that express both KATP and TRPA1 channels. RIN14B cells showed several intracellular Ca(2+) concentration ([Ca(2+)]i) responses to NaHS (300 µM), an H2S donor, i.e., inhibition of spontaneous Ca(2+) oscillations (37%), inhibition followed by [Ca(2+)]i increase (24%), and a rapid increase in [Ca(2+)]i (25%). KATP channel blockers, glibenclamide or tolbutamide, abolished any inhibitory effects of NaHS and enhanced NaHS-mediated [Ca(2+)]i increases, which were inhibited by extracellular Ca(2+) removal, HC030031 (a TRPA1 antagonist), and disulfide bond-reducing agents. NaHS induced 5-hydroxytryptamine (5-HT) release from RIN14B cells, which was also inhibited by TRPA1 antagonists. These results indicate that H2S has both inhibitory and excitatory effects by opening KATP and TRPA1 channels, respectively, in RIN14B cells, suggesting potential bidirectional modulation of secretory functions.
Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Sulfeto de Hidrogênio/farmacologia , Canais KATP/efeitos dos fármacos , Células Secretoras de Somatostatina/efeitos dos fármacos , Sulfetos/farmacologia , Canais de Cátion TRPC/efeitos dos fármacos , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Sulfeto de Hidrogênio/metabolismo , Ativação do Canal Iônico/efeitos dos fármacos , Canais KATP/genética , Canais KATP/metabolismo , Cinética , Potenciais da Membrana , Ratos , Serotonina/metabolismo , Células Secretoras de Somatostatina/metabolismo , Sulfetos/metabolismo , Canal de Cátion TRPA1 , Canais de Cátion TRPC/genética , Canais de Cátion TRPC/metabolismoRESUMO
Adenosine kinase (AK) inhibitor is a potential candidate for controlling pain, but some AK inhibitors have problems of adverse effects such as motor impairment. ABT-702, a non-nucleoside AK inhibitor, shows analgesic effect in animal models of pain. Here, we investigated the effects of ABT-702 on synaptic transmission via nociceptive and motor reflex pathways in the isolated spinal cord of neonatal rats. The release of adenosine from the spinal cord was measured by HPLC. ABT-702 inhibited slow ventral root potentials (sVRPs) in the nociceptive pathway more potently than monosynaptic reflex potentials (MSRs) in the motor reflex pathway. The inhibitory effects of ABT-702 were mimicked by exogenously applied adenosine, blocked by 8CPT (8-cyclopentyl-1,3-dipropylxanthine), an adenosine A1 receptor antagonist, and augmented by EHNA (erythro-9-(2-hydroxy-3-nonyl) adenine), an adenosine deaminase (ADA) inhibitor. Equilibrative nucleoside transporter (ENT) inhibitors reversed the effects of ABT-702, but not those of adenosine. ABT-702 released adenosine from the spinal cord, an effect that was also reversed by ENT inhibitors. The ABT-702-facilitated release of adenosine by way of ENTs inhibits nociceptive pathways more potently than motor reflex pathways in the spinal cord via activation of A1 receptors. This feature is expected to lead to good analgesic effects, but, caution may be required for the use of AK inhibitors in the case of ADA dysfunction or a combination with ENT inhibitors.
Assuntos
Adenosina Quinase/antagonistas & inibidores , Analgésicos/farmacologia , Morfolinas/farmacologia , Neurônios Motores/efeitos dos fármacos , Dor Nociceptiva/tratamento farmacológico , Pirimidinas/farmacologia , Medula Espinal/efeitos dos fármacos , Adenina/análogos & derivados , Adenina/farmacologia , Adenosina/metabolismo , Antagonistas do Receptor A1 de Adenosina/farmacologia , Adenosina Desaminase/metabolismo , Adenosina Quinase/metabolismo , Animais , Animais Recém-Nascidos , Inibidores Enzimáticos/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Neurônios Motores/fisiologia , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiopatologia , Dor Nociceptiva/fisiopatologia , Reflexo/efeitos dos fármacos , Reflexo/fisiologia , Medula Espinal/fisiopatologia , Técnicas de Cultura de Tecidos , Xantinas/farmacologiaRESUMO
Alpha-2A adrenergic receptor (AR) subtype plays an important role in the analgesic effect of α2-AR agonists. Here, we examined the effects of α2-AR agonists, dexmedetomidine and xylazine, on spinal synaptic transmission in newborn C57BL/6J and α2A-AR mutant mice. Spinal reflex potentials, the monosynaptic reflex potential (MSR) and the slow ventral root potential (sVRP), were measured in isolated spinal cords. The compound action potential was measured in isolated lumbar nerve. Dexmedetomidine and xylazine suppressed both the MSR and sVRP in a concentration-dependent manner. In α2A-AR mutant mice, sVRP suppression by dexmedetomidine was greatly weakened, while that by xylazine (30-100µM) showed only slight attenuation. A high concentration (300µM) of xylazine completely suppressed the sVRP, even in α2A-AR mutant mice spinal cords, and also suppressed the compound action potential. MSR suppression by these α2-AR agonists had no difference between wild-type and α2A-AR mutant mice. These results suggest that sVRP suppression by dexmedetomidine and xylazine is mainly mediated by α2A-AR. In addition, a high concentration of xylazine inhibits conduction of the action potential, which is not mediated by α2A-AR. α2-AR is not responsible for the dexmedetomidine- and xylazine-mediated inhibition of the MSR.
Assuntos
Neurônios Adrenérgicos/efeitos dos fármacos , Agonistas de Receptores Adrenérgicos alfa 2/farmacologia , Dexmedetomidina/farmacologia , Receptores Adrenérgicos alfa 2/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , Xilazina/farmacologia , Potenciais de Ação , Neurônios Adrenérgicos/metabolismo , Animais , Animais Recém-Nascidos , Relação Dose-Resposta a Droga , Feminino , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Inibição Neural/efeitos dos fármacos , Ratos Wistar , Receptores Adrenérgicos alfa 2/deficiência , Receptores Adrenérgicos alfa 2/genética , Receptores Adrenérgicos alfa 2/metabolismo , Reflexo/efeitos dos fármacos , Medula Espinal/citologia , Medula Espinal/metabolismo , Fatores de TempoRESUMO
Extracellular adenosine is a neuromodulator in the central nervous system. Astrocytes mainly participate in adenosine production, and extracellular adenosine accumulates under physiological and pathophysiological conditions. Inhibition of intracellular adenosine metabolism and reduction of the external Ca(2+) concentration ([Ca(2+)]e) participate in adenosine accumulation, but the precise mechanisms remain unclear. This study investigated the mechanisms underlying extracellular adenosine accumulation in cultured rat spinal astrocytes. The combination of adenosine kinase and deaminase (ADK/ADA) inhibition and a reduced [Ca(2+)]e increased the extracellular adenosine level. ADK/ADA inhibitors increased the level of extracellular adenosine but not of adenine nucleotides, which was suppressed by inhibition of equilibrative nucleoside transporter (ENT) 2. Unlike ADK/ADA inhibition, a reduced [Ca(2+)]e increased the extracellular level not only of adenosine but also of ATP. This adenosine increase was enhanced by ENT2 inhibition, and suppressed by sodium polyoxotungstate (ecto-nucleoside triphosphate diphosphohydrolase inhibitor). Gap junction inhibitors suppressed the increases in adenosine and adenine nucleotide levels by reduction of [Ca(2+)]e. These results indicate that extracellular adenosine accumulation by ADK/ADA inhibition is due to the adenosine release via ENT2, while that by reduction of [Ca(2+)]e is due to breakdown of ATP released via gap junction hemichannels, after which ENT2 incorporates adenosine into the cells.
Assuntos
Adenosina/metabolismo , Adenosina/fisiologia , Astrócitos/metabolismo , Cálcio/metabolismo , Medula Espinal/citologia , Adenosina Desaminase , Inibidores de Adenosina Desaminase/farmacologia , Adenosina Quinase/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Animais , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Transportador Equilibrativo 2 de Nucleosídeo/antagonistas & inibidores , Transportador Equilibrativo 2 de Nucleosídeo/fisiologia , Junções Comunicantes/efeitos dos fármacos , Neurotransmissores , Ratos WistarRESUMO
Cystathionine ß-synthase (CBS), expressed in astrocytes, generates a gaseous neuromodulator, hydrogen sulfide (H2S) in the central nervous system (CNS). However, little is known about the regulatory mechanisms of astrocytic CBS expression and activity. This study evaluated the influence of neurons on astrocytic CBS expression by employing multiple culture systems. Substantial CBS expression was observed in the intact neonatal rat spinal cord, while CBS content was markedly reduced in an astrocyte-enriched culture prepared from the neonatal spinal cord. Immunofluorescence analysis confirmed the localization of spinal cord CBS in astrocytes, but not in neurons. Although CBS expression was weak in the embryonic rat spinal cord, enzyme levels were time-dependently increased in a neuron/astrocyte mixed culture originating from embryonic spinal cord. The reduced CBS expression in isolated neonatal astrocytes was restored by co-culture with embryonic neurons. Together with the observed CBS expression levels, H2S production was relatively low in astrocytes cultured alone, but was considerably higher in astrocytes cultured with neurons. These results indicate that neurons are essential for maintaining the expression and H2S-producing activity of astrocytic CBS in the rat spinal cord.
Assuntos
Astrócitos/enzimologia , Cistationina beta-Sintase/metabolismo , Neurônios/enzimologia , Medula Espinal/enzimologia , Animais , Animais Recém-Nascidos , Astrócitos/metabolismo , Células Cultivadas , Técnicas de Cocultura , Sulfeto de Hidrogênio/metabolismo , Neurônios/metabolismo , Ratos , Ratos Wistar , Medula Espinal/metabolismoRESUMO
Transient receptor potential (TRP) channel melastatin subfamily member 4 (TRPM4) is a broadly expressed nonselective monovalent cation channel. TRPM4 is activated by membrane depolarization and intracellular Ca(2+), which is essential for the activation. The Ca(2+) sensitivity is known to be regulated by calmodulin and membrane phosphoinositides, such as phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). Although these regulators must play important roles in controlling TRPM4 activity, mutation analyses of the calmodulin-binding sites have suggested that Ca(2+) binds to TRPM4 directly. However, the intrinsic binding sites in TRPM4 remain to be elucidated. Here, by using patch clamp and molecular biological techniques, we show that there are at least two functionally different divalent cation-binding sites, and the negatively charged amino acids near and in the TRP domain in the C-terminal tail of TRPM4 (Asp-1049 and Glu-1062 of rat TRPM4) are required for maintaining the normal Ca(2+) sensitivity of one of the binding sites. Applications of Co(2+), Mn(2+), or Ni(2+) to the cytosolic side potentiated TRPM4 currents, increased the Ca(2+) sensitivity, but were unable to evoke TRPM4 currents without Ca(2+). Mutations of the acidic amino acids near and in the TRP domain, which are conserved in TRPM2, TRPM5, and TRPM8, deteriorated the Ca(2+) sensitivity in the presence of Co(2+) or PI(4,5)P2 but hardly affected the sensitivity to Co(2+) and PI(4,5)P2. These results suggest a novel role of the TRP domain in TRPM4 as a site responsible for maintaining the normal Ca(2+) sensitivity. These findings provide more insights into the molecular mechanisms of the regulation of TRPM4 by Ca(2+).
Assuntos
Ácido Aspártico/metabolismo , Cálcio/metabolismo , Ácido Glutâmico/metabolismo , Canais de Cátion TRPM/metabolismo , Animais , Ácido Aspártico/genética , Sítios de Ligação/genética , Cálcio/farmacologia , Cátions Bivalentes/metabolismo , Cátions Bivalentes/farmacologia , Cobalto/metabolismo , Cobalto/farmacologia , Ácido Glutâmico/genética , Células HEK293 , Humanos , Masculino , Potenciais da Membrana/efeitos dos fármacos , Mutação , Técnicas de Patch-Clamp , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositol 4,5-Difosfato/farmacologia , Ratos Endogâmicos BN , Canais de Cátion TRPM/genética , Canais de Cátion TRPM/fisiologia , TransfecçãoRESUMO
Hydrogen sulfide (H2 S) is a gaseous neuromodulator produced from L-cysteine. H2 S is generated by three distinct enzymatic pathways mediated by cystathionine γ-lyase (CSE), cystathionine ß-synthase (CBS), and mercaptopyruvate sulfurtransferase (MPST) coupled with cysteine aminotransferase (CAT). This study investigated the relative contributions of these three pathways to H2 S production in PC12 cells (rat pheochromocytoma-derived cells) and the rat dorsal root ganglion. CBS, CAT, and MPST, but not CSE, were expressed in the cells and tissues, and appreciable amounts of H2 S were produced from L-cysteine in the presence of α-ketoglutarate, together with dithiothreitol. The production of H2 S was inhibited by a CAT inhibitor (aminooxyacetic acid), competitive CAT substrates (L-aspartate and oxaloacetate), and RNA interference (RNAi) against MPST. Immunocytochemistry revealed a mitochondrial localization of MPST in PC12 cells and dorsal root ganglion neurons, and the amount of H2 S produced by CAT/MPST at pH 8.0, a physiological mitochondrial matrix pH, was comparable to that produced by CSE and CBS in the liver and the brain, respectively. Furthermore, H2 S production was markedly increased by alkalization. These results indicate that CAT and MPST are primarily responsible for H2 S production in peripheral neurons, and that the regulation of mitochondrial metabolism may influence neuronal H2 S generation. In the peripheral nervous system, hydrogen sulfide (H2 S) has been implicated in neurogenic pain or hyperalgesia. This study provides evidence that H2 S is synthesized in peripheral neurons through two mitochondrial enzymes, cysteine aminotransferase (CAT) and mercaptopyruvate sulfurtransferase (MPST). We propose that mitochondrial metabolism plays key roles in the physiology and pathophysiology of the peripheral nervous system via regulation of neuronal H2 S production.
Assuntos
Gânglios Espinais/metabolismo , Sulfeto de Hidrogênio/metabolismo , Neurônios/metabolismo , Sulfurtransferases/fisiologia , Transaminases/fisiologia , Animais , Gânglios Espinais/enzimologia , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/fisiologia , Neurônios/enzimologia , Células PC12 , Ratos , Ratos WistarRESUMO
The mechanism of reaction between peroxodisulfate ion (S2O8(2-)), selenite (Se(IV)O3(2-)) and Mn(2+) as an inhibitor of selenite oxidation was studied using aqueous solutions composed of commercial reagents, as well as limestone-gypsum flue gas desulfurization (FGD) liquors sampled from coal fired power plants. The oxidation of selenite to selenate (Se(VI)O4(2-)) is promoted by the sulfate ion radical (SO4(-)) which results from decomposition of S2O8(2-). In the presence of Mn(2+), selenite oxidation was prevented due to the difference in rates of reaction with SO4(-). The ratio of the oxidation rate constants of selenite and Mn(2+) with SO4(-) was determined over a temperature range of 40-60 °C, and was found to be little influenced by the various coexisting components in FGD liquors.
Assuntos
Carbonato de Cálcio/química , Sulfato de Cálcio/química , Manganês/química , Compostos de Potássio/química , Ácido Selenioso/química , Sulfatos/química , Resíduos Industriais , Oxirredução , Centrais Elétricas , SoluçõesRESUMO
Serotonin (5-HT) released from descending fibers plays important roles in spinal functions such as locomotion and nociception. 5-HT2A and 5-HT3 receptors are suggested to contribute to spinal antinociception, although their activation also contributes to neuronal excitation. In the neonatal spinal cord, DL-p-chloroamphetamine (pCA), a 5-HT releaser, inhibited both A fiber-evoked monosynaptic reflex potential (MSR) and C fiber-evoked slow ventral root potential (sVRP). The pCA-mediated inhibition was reversed by ketanserin (a 5-HT2A receptor antagonist) and tropisetron (a 5-HT3 receptor antagonist). Bath-applied 5-HT also inhibited MSR and sVRP; in this case, the actions of 5-HT were antagonized by ketanserin, but not by tropisetron. The pCA-evoked inhibition of sVRP was reduced by bicuculline (a GABAA receptor antagonist) and strychnine (a glycine receptor antagonist). Furthermore, ketanserin inhibited the pCA-evoked release of gamma-aminobutyric acid (GABA) and glycine, while tropisetron inhibited the pCA-evoked release of 5-HT. These results suggest that 5-HT released by pCA activates 5-HT2A receptors, which in turn stimulates the release of GABA/glycine and thereby blocks the spinal nociceptive pathway. 5-HT3 receptors may be involved in the facilitation of 5-HT release via a positive feedback process.
Assuntos
Fibras Nervosas Mielinizadas/fisiologia , Fibras Nervosas Amielínicas/fisiologia , Receptor 5-HT2A de Serotonina/fisiologia , Receptores 5-HT3 de Serotonina/fisiologia , Serotonina/fisiologia , Medula Espinal/fisiologia , Animais , Animais Recém-Nascidos , Feminino , Glicina/metabolismo , Técnicas In Vitro , Masculino , Ratos , Ratos Wistar , Transmissão Sináptica/fisiologia , Ácido gama-Aminobutírico/metabolismoRESUMO
Hydrogen sulfide (H(2)S) is considered as a gasotransmitter. Although several reports have shown that H(2)S stimulates sensory neurons, the primary targets of H(2)S remain controversial. We investigated the effects of H(2)S on cultured sensory neurons isolated from rat dorsal root ganglion (DRG) using Ca(2+) imaging and whole-cell voltage-clamp techniques. Brief (2 min) application of NaHS (1mM), a donor of H(2)S, evoked marked increases in intracellular Ca(2+) concentration ([Ca(2+)](i)) in a subset of DRG neurons. These neurons also responded to both capsaicin and mustard oil (MO), transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) agonists, respectively. The NaHS-evoked [Ca(2+)](i) increases were inhibited by a removal of external Ca(2+) and antagonists for TRPA1, but not for TRPV1 or voltage-dependent Ca(2+) channels. At -80 mV, NaHS evoked inward currents in MO-sensitive neurons, which were also inhibited by a TRPA1 antagonist. Even at lower concentration (≤1 µM), the 10-min application of NaHS increased [Ca(2+)](i) in a time- and concentration-dependent manner. These results suggest that H(2)S stimulates sensory neurons via activation of TRPA1. Endogenous H(2)S may be involved in physiological processes through TRPA1.
Assuntos
Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Sulfeto de Hidrogênio/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Canais de Cátion TRPC/metabolismo , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Feminino , Gânglios Espinais/citologia , Masculino , Ratos , Ratos Wistar , Canal de Cátion TRPA1 , Canais de Cátion TRPC/agonistas , Fatores de TempoRESUMO
We have examined the effects of repetitive transcranial magnetic stimulation (rTMS) on central dopaminergic function in patients with depression using positron emission tomography with L-[ß-11C]DOPA, a ligand to assess the rate of endogenous dopamine synthesis. Eight patients were treated with 10-daily sessions of rTMS over the left dorsolateral prefrontal cortex. Positron emission tomography scanning was performed in each patient twice, before the first session and 1 day after the last session. Although four out of eight patients responded to rTMS, there were no changes in the striatal dopamine synthesis rate (k) following rTMS. These results suggest that chronic rTMS had a limited effect on the dopaminergic system.
Assuntos
Encéfalo/metabolismo , Transtorno Depressivo Maior/metabolismo , Transtorno Depressivo Maior/terapia , Dopamina/biossíntese , Levodopa , Tomografia por Emissão de Pósitrons/métodos , Estimulação Magnética Transcraniana/métodos , Adulto , Encéfalo/diagnóstico por imagem , Radioisótopos de Carbono , Transtorno Depressivo Maior/diagnóstico por imagem , Feminino , Humanos , MasculinoRESUMO
The recombinant human erythropoietin (rhEPO) is used for the treatment of patients with renal anemia. However, rhEPO should be administered subcutaneously or intravenously three times a week. The repetitive injections of rhEPO result in burdens to patients. To resolve this problem, we investigated the sustaining release methods using an rhEPO-hydroxyapatite (HAp) made by spray-drying technique as the drug delivery system. Two types of rhEPO-HAp formulations were prepared; zinc (Zn) formulation and Zn and poly-L-lactic acid (PLA) formulation. These formulations were examined in genetically anemic model, ICGN (ICR-derived glomerulonephritis) mice. According to in vivo release test of rhEPO from HAp in ICGN mice, elevated plasma concentration of rhEPO could be maintained for more than 7 days. These mice showed the amelioration of anemia for more than 3 weeks post-administration without causing any side effect. In conclusion, Zn or Zn/PLA formulation of HAp was considered to be one of the useful carriers of rhEPO for long-term improvement of anemia.
Assuntos
Anemia/tratamento farmacológico , Durapatita/química , Eritropoetina/administração & dosagem , Eritropoetina/farmacologia , Animais , Preparações de Ação Retardada , Eritropoetina/química , Glomerulonefrite/complicações , Glomerulonefrite/tratamento farmacológico , Humanos , Camundongos , Camundongos Endogâmicos , Proteínas Recombinantes , Organismos Livres de Patógenos Específicos , Fatores de TempoRESUMO
For chronic kidney disease patients with renal anemia, recombinant human erythropoietin (rHuEPO) is a very effective drug; however, the treatment regime is troublesome, requiring multiple administrations each week. In the present study, we examined the efficiency of hydroxyapatite (HAp) as a drug delivery carrier for the sustained release of erythropoietin (EPO) to reduce the frequency of administration. Spray-dried HAp microparticles, formed from zinc-containing HAp (Zn-HAp) and Zn-HAp calcined at 400 degrees C, were used as carriers of EPO, and five Zn-HAp formulation samples incorporating EPO were prepared; no formulation, poly-L-lactic acid (PLA) formulation, zinc (Zn) formulation, Zn/PLA formulation, and calcined/Zn/PLA formulation. ICR mice were administered these samples or commercial rHuEPO (Epogin) as a control from dorsal neck subcutaneous, and hematological and histopathological analyses, including enzyme-linked immunosorbent assay for plasma EPO concentration, were performed. An increase in the blood EPO level was detected on days 3 and 8 post-administration. Peak hematopoiesis was delayed and higher hematological values were obtained on day 14 post-administration with no serious adverse reactions compared with the control. The Zn/PLA formulation sample was found to be most effective in reducing the initial peak while sustaining the delayed release of EPO. In conclusion, the Zn-HAp formulation samples were considered to be useful carriers for the sustained release of EPO, and the Zn/PLA formulation appears to be the most effective of five Zn-HAp formulation samples in sustaining EPO release.
Assuntos
Anemia/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Eritropoetina/administração & dosagem , Hidroxiapatitas/administração & dosagem , Anemia/sangue , Animais , Preparações de Ação Retardada , Contagem de Eritrócitos , Eritropoetina/sangue , Hematócrito , Hemoglobinas/metabolismo , Injeções Subcutâneas , Masculino , Camundongos , Camundongos Endogâmicos ICR , Microscopia Eletrônica de Varredura , Microesferas , Tamanho do Órgão/efeitos dos fármacos , Proteínas Recombinantes , Organismos Livres de Patógenos EspecíficosRESUMO
PURPOSE: To report a case of optic neuritis associated with cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). CASE: A 38-year-old woman presented with visual field defects, ocular pain and relative afferent papillary defect (RAPD). Fluorescein angiography demonstrated peripapillary hyperfluorescence of the optic nerve. Optic neuritis was diagnosed soon after. Routine laboratory data were unremarkable. Brain MRI showed a remarkable enhanced region of white matter and abnormal spots in the capsula externa. Multiple sclerosis was outruled by neurological findings and therefore CARASIL was diagnosed according to the criteria. The patient's vision and inflammation of the optic nerve head gradually improved with systemic steroid therapy, but arterial sheathing was observed during the follow-up period. CONCLUSIONS: Clinical manifestations such as optic neuritis and retinal vascular change might be caused by the pathological changes of CARASIL. This is the first report of ophthalmic findings of clinicopathological events of CARASIL.