RESUMEN
Exposure to stress plays a detrimental role in the pathogenesis of hypertension via neuroinflammation pathways. Microglial neuroinflammation in the rostral ventrolateral medulla (RVLM) exacerbates stress-induced hypertension (SIH) by increasing sympathetic hyperactivity. Mitochondria of microglia are the regulators of innate immune response. Sigma-1R (σ-1R) localizes to the mitochondria-associated membranes (MAMs) and regulates endoplasmic reticulum (ER) and mitochondria communication, in part through its chaperone activity. The present study aims to investigate the protective role of σ-1R on microglial-mediated neuroinflammation. Stress-induced hypertension (SIH) was induced in rats using electric foot shocks and intermittent noise. Arterial blood pressure (ABP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were measured to evaluate the sympathetic nervous system (SNS) activities. SKF10047 (100 µM), an agonist of σ-1R, was administrated to rats, then σ-1R localization and MAM alterations were detected by immuno-electron microscopy. Mitochondrial calcium homeostasis was examined in primary microglia and/or BV-2 microglia cells. The effect of SKF10047 treatment on the mitochondrial respiratory function of cultured microglia was measured using a Seahorse Extracellular Flux Analyzer. Confocal microscopic images were performed to indicate mitochondrial dynamics. Stress reduces σ-1R's localization at the MAMs, leading to decreased ER-mitochondria contact and IP3R-GRP75-VDAC calcium transport complexes expression in the RVLM of rats. SKF10047 promotes the length and coverage of MAMs in the prorenin-treated microglia. Prorenin treatment increases mitoROS levels, and inhibits Ca2+ signalling between the two organelles, therefore negatively affects ATP production in BV2 cells, and these effects are reversed by SKF10047 treatment. We found mitochondrial hyperfusion and microglial M1 polarization in prorenin-treated microglia. SKF10047 suppresses microglial M1 polarization and RVLM neuroinflammation, subsequently ameliorates sympathetic hyperactivity in stress-induced hypertensive rats. Sigma-1 receptor activation suppresses microglia M1 polarization and neuroinflammation via regulating endoplasmic reticulum-mitochondria contact and mitochondrial functions in stress-induced hypertension rats.
Asunto(s)
Retículo Endoplásmico/metabolismo , Hipertensión/metabolismo , Microglía/metabolismo , Mitocondrias/metabolismo , Receptores sigma/agonistas , Animales , Presión Sanguínea/fisiología , Calcio/metabolismo , Polaridad Celular/efectos de los fármacos , Electrochoque/efectos adversos , Retículo Endoplásmico/efectos de los fármacos , Frecuencia Cardíaca/fisiología , Hipertensión/etiología , Hipertensión/fisiopatología , Mitocondrias/efectos de los fármacos , Fenazocina/análogos & derivados , Fenazocina/farmacología , Ratas , Sistema Nervioso Simpático/metabolismo , Sistema Nervioso Simpático/fisiopatología , Receptor Sigma-1RESUMEN
Mitochondria are essential for neuronal survival and function, and mitochondrial dysfunction plays a critical role in the pathological development of Parkinson's disease (PD). Mitochondrial quality control is known to contribute to the survival of dopaminergic (DA) neurons, with mitophagy being a key regulator of the quality control system. In this study, we show that mitophagy is impaired in the substantia nigra pars compacta (SNc) of the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. Treatment with the sigma-1 receptor (Sig 1R) agonist 2-morpholin-4-ylethyl 1-phenylcyclohexane-1-carboxylate (PRE-084) reduced loss of DA neurons, restored motor ability and MPTP-induced damage to mitophagy activity in the SNc of PD-like mice. Additionally, knockdown of Sig 1R in SH-SY5Y DA cells inhibited mitophagy and enhanced 1-methyl-4-phenylpyridinium ion (MPP+) neurotoxicity, whereas application of the Sig 1R selective agonist SKF10047 promoted clearance of damaged mitochondria. Moreover, knockdown of Sig 1R in SH-SY5Y cells resulted in decreased levels of p-ULK1 (Unc-51 Like Autophagy Activating Kinase 1) (Ser555), p-TBK1 (TANK Binding Kinase 1) (Ser172), p-ubiquitin (Ub) (Ser65), Parkin recruitment, and stabilization of PTEN-induced putative kinase 1 (PINK1) in mitochondria. The present data provide the first evidence for potential roles of PINK1/Parkin in Sig 1R-modulated mitophagy in DA neurons.
Asunto(s)
Neuronas Dopaminérgicas/metabolismo , Mitocondrias/metabolismo , Mitofagia/genética , Trastornos Parkinsonianos/metabolismo , Proteínas Quinasas/metabolismo , Receptores sigma/genética , Ubiquitina-Proteína Ligasas/metabolismo , 1-Metil-4-fenilpiridinio/toxicidad , Animales , Homólogo de la Proteína 1 Relacionada con la Autofagia/efectos de los fármacos , Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Línea Celular , Neuronas Dopaminérgicas/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Ratones , Mitocondrias/efectos de los fármacos , Mitofagia/efectos de los fármacos , Morfolinas/farmacología , Trastornos Parkinsonianos/genética , Trastornos Parkinsonianos/patología , Porción Compacta de la Sustancia Negra/efectos de los fármacos , Porción Compacta de la Sustancia Negra/metabolismo , Porción Compacta de la Sustancia Negra/patología , Fenazocina/análogos & derivados , Fenazocina/farmacología , Fosforilación , Proteínas Quinasas/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/metabolismo , Estabilidad Proteica/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos , Receptores sigma/agonistas , Receptores sigma/metabolismo , Transducción de Señal , Sustancia Negra/efectos de los fármacos , Sustancia Negra/metabolismo , Sustancia Negra/patología , Ubiquitina/efectos de los fármacos , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligasas/efectos de los fármacos , Receptor Sigma-1RESUMEN
Expression of Kv1.2 within Kv1.x potassium channel complexes is critical in maintaining appropriate neuronal excitability and determining the threshold for action potential firing. This is attributed to the interaction of Kv1.2 with a hitherto unidentified protein that confers bimodal channel activation gating, allowing neurons to adapt to repetitive trains of stimulation and protecting against hyperexcitability. One potential protein candidate is the sigma-1 receptor (Sig-1R), which regulates other members of the Kv1.x channel family; however, the biophysical nature of the interaction between Sig-1R and Kv1.2 has not been elucidated. We hypothesized that Sig-1R may regulate Kv1.2 and may further act as the unidentified modulator of Kv1.2 activation. In transiently transfected HEK293 cells, we found that ligand activation of the Sig-1R modulates Kv1.2 current amplitude. More importantly, Sig-1R interacts with Kv1.2 in baseline conditions to influence bimodal activation gating. These effects are abolished in the presence of the auxiliary subunit Kvß2 and when the Sig-1R mutation underlying ALS16 (Sig-1R-E102Q), is expressed. These data suggest that Kvß2 occludes the interaction of Sig-1R with Kv1.2, and that E102 may be a residue critical for Sig-1R modulation of Kv1.2. The results of this investigation describe an important new role for Sig-1R in the regulation of neuronal excitability and introduce a novel mechanism of pathophysiology in Sig-1R dysfunction.
Asunto(s)
Canal de Potasio Kv.1.2/fisiología , Receptores sigma/fisiología , Células Cultivadas , Fenómenos Electrofisiológicos/efectos de los fármacos , Fenómenos Electrofisiológicos/fisiología , Células HEK293 , Humanos , Activación del Canal Iónico/fisiología , Canal de Potasio Kv.1.2/efectos de los fármacos , Canal de Potasio Kv.1.2/metabolismo , Técnicas de Placa-Clamp/métodos , Fenazocina/análogos & derivados , Fenazocina/antagonistas & inhibidores , Fenazocina/farmacología , Receptores sigma/agonistas , Receptores sigma/metabolismo , Canales de Potasio de la Superfamilia Shaker/fisiología , Receptor Sigma-1RESUMEN
Astrocyte is considered to be a type of passive supportive cells that preserves neuronal activity and survival. The dysfunction of astrocytes is involved in the pathological processes of major depression. Recent studies implicate sigma-1 receptors as putative therapeutic targets for current available antidepressant drugs. However, it is absent of direct evidences whether sigma-1 receptor could promote activation of astrocyte. In the present study, we took advantage of primary astrocyte culture and a highly selective agonist of sigma-1 receptor, (+)SKF-10047 to determine the effect of sigma-1 receptor on Brdu (bromodeoxyuridine) labeling positive cells, migration as well as GFAP (glial fibrillary acidic protein) expression of astrocyte. The results showed that (+)SKF-10047 notably increased the number of Brdu labeling positive cells, migration, and the expression of GFAP in primary astrocytes, which were blocked by antagonist of sigma-1 receptor. Moreover, we also found that (+)SKF-10047 increased the phosphorylation of ERK1/2 (extracellular signal-regulated kinases 1/2) and GSK3ß (glycogen synthase kinase 3ß) (ser 9) in the primary astrocytes. In addition, pharmacological inhibition of ERK1/2 and GSK3ß (ser 9) abolished sigma-1 receptor-promoted activation of astrocyte. Therefore, sigma-1 receptor could be considerate as a new pattern for modulating astrocytic function might emerge as therapeutic strategies.
Asunto(s)
Astrocitos/efectos de los fármacos , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Fenazocina/análogos & derivados , Receptores sigma/agonistas , Animales , Astrocitos/metabolismo , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Técnicas de Silenciamiento del Gen , Proteína Ácida Fibrilar de la Glía/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Ratones Endogámicos C57BL , Fenazocina/farmacología , Fosforilación , Cultivo Primario de Células , Receptores sigma/genética , Transducción de Señal , Receptor Sigma-1RESUMEN
The serotonin transporter (SERT) is functionally regulated via membrane trafficking. Our previous studies have demonstrated that the SERT C-terminal deletion mutant (SERTΔCT) showed a robust decrease in its membrane trafficking and was retained in the endoplasmic reticulum (ER), suggesting that SERTΔCT is an unfolded protein that may cause ER stress. The Sigma-1 receptor (SigR1) has been reported to attenuate ER stress via its chaperone activity. In this study, we investigated the effects of SKF-10047, a prototype SigR1 agonist, on the membrane trafficking and uptake activity of SERT and SERTΔCT expressed in COS-7 cells. Twenty-four hours of SKF-10047 treatment (>200 µM) accelerated SERT membrane trafficking and robustly upregulated SERTΔCT activity. Interestingly, these effects of SKF-10047 on SERT functions were also found in cells in which SigR1 expression was knocked down by shRNA, suggesting that SKF-10047 exerted these effects on SERT via a mechanism independent of SigR1. A cDNA array study identified several candidate genes involved in the mechanism of action of SKF-10047. Among them, Syntaxin3, a member of the SNARE complex, was significantly upregulated by 48 h of SKF-10047 treatment. These results suggest that SKF-10047 is a candidate for ER stress relief.
Asunto(s)
Membrana Celular/efectos de los fármacos , Fenazocina/análogos & derivados , Receptores sigma/agonistas , Proteínas de Transporte de Serotonina en la Membrana Plasmática/fisiología , Animales , Células COS , Membrana Celular/metabolismo , Chlorocebus aethiops , Estrés del Retículo Endoplásmico , Técnicas de Silenciamiento del Gen , Mutación , Fenazocina/farmacología , Transporte de Proteínas , Receptores sigma/genética , Receptor Sigma-1RESUMEN
cis-N-Substituted N-normetazocine enantiomers possess peculiar pharmacological profiles. Indeed, dextro enantiomers bind with high affinity σ1 receptor while opposite enantiomers bind opioid receptors. In spite of their stereochemistry, cis-N-2-phenylethyl N-normetazocine (phenazocine) enantiomers showed mixed opioid/σ1 receptor profiles and a significant in vivo analgesia. To the best of our knowledge, there is no information available regarding the evaluation of σ1 pharmacological profile in the antinociceptive effects of (+)- and (-)-phenazocine. Therefore, the present study was designed to ascertain this component by in vitro and in vivo studies. In particular, we tested the σ1 affinity of both enantiomers by a predictive binding assay in absence or presence of phenytoin (DPH). Our results showed that DPH (1 mM) did not increase the σ1 receptor affinity of (+)-and (-)-phenazocine (Ki = 3.8 ± 0.4 nM, Ki = 85 ± 2.0 nM, respectively) suggesting a σ1 antagonist profile of both enantiomers. This σ1 antagonistic component of two phenazocine enantiomers was corroborated by in vivo studies in which the selective σ1 receptor agonist PRE-084, was able to unmask their σ1 antagonistic component associated with the opioid activity. The σ1 antagonistic component of (+)- and (-)-phenazocine may justify their analgesic activity and it suggests that they may constitute useful lead compounds to develop new ligands with this dual activity.
Asunto(s)
Antagonistas de Narcóticos/síntesis química , Antagonistas de Narcóticos/farmacología , Fenazocina/síntesis química , Fenazocina/farmacología , Receptores Opioides/agonistas , Analgésicos/síntesis química , Analgésicos/química , Analgésicos/farmacología , Animales , Sitios de Unión , Ratones , Estructura Molecular , Morfolinas/química , Morfolinas/farmacología , Antagonistas de Narcóticos/química , Dolor/tratamiento farmacológico , Dimensión del Dolor , Fenazocina/química , Unión Proteica/efectos de los fármacos , EstereoisomerismoRESUMEN
Sigma receptor (σR), a unique receptor family, is classified into three subtypes: σR1, σR2 and σR3. It was previously shown that σR1 activation induced by 1µM SKF10047 (SKF) suppressed N-methyl-d-aspartate (NMDA) receptor-mediated responses of rat retinal ganglion cells (GCs) and the suppression was mediated by a distinct Ca(2+)-dependent phospholipase C (PLC)-protein kinase C (PKC) pathway. In the present work, using whole-cell patch-clamp techniques in rat retinal slice preparations, we further demonstrate that SKF of higher dosage (50µM) significantly suppressed AMPA receptor (AMPAR)-mediated light-evoked excitatory postsynaptic currents (L-EPSCs) of retinal ON-type GCs (ON GCs), and the effect was reversed by the σR1 antagonist BD1047, suggesting the involvement of σR1. The SKF (50µM) effect was unlikely due to a change in glutamate release from bipolar cells, as suggested by the unaltered paired-pulse ratio (PPR) of AMPAR-mediated EPSCs of ON GCs. SKF (50µM) did not change L-EPSCs of ON GCs when the G protein inhibitor GDP-ß-S or the protein kinase G (PKG) inhibitor KT5823 was intracellularly infused. Calcium imaging further revealed that SKF (50µM) did not change intracellular calcium concentration in GCs and persisted to suppress L-EPSCs when intracellular calcium was chelated by BAPTA. The SKF (50µM) effect was intact when protein kinase A (PKA) and phosphatidylinostiol (PI)-PLC signaling pathways were both blocked. We conclude that the SKF (50µM) effect is Ca(2+)-independent, PKG-dependent, but not involving PKA, PI-PLC pathways.
Asunto(s)
Potenciales Postsinápticos Excitadores/fisiología , Receptores AMPA/metabolismo , Receptores sigma/metabolismo , Células Ganglionares de la Retina/metabolismo , Visión Ocular/fisiología , Animales , Calcio/metabolismo , Carbazoles/farmacología , Células Cultivadas , Fármacos del Sistema Nervioso Central/farmacología , Proteínas Quinasas Dependientes de GMP Cíclico/antagonistas & inhibidores , Proteínas Quinasas Dependientes de GMP Cíclico/metabolismo , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Etilenodiaminas/farmacología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Ácido Glutámico/metabolismo , Luz , Masculino , Técnicas de Placa-Clamp , Fenazocina/análogos & derivados , Fenazocina/farmacología , Ratas Sprague-Dawley , Receptores sigma/antagonistas & inhibidores , Células Ganglionares de la Retina/efectos de los fármacos , Técnicas de Cultivo de Tejidos , Visión Ocular/efectos de los fármacos , Imagen de Colorante Sensible al VoltajeRESUMEN
RATIONALE: We previously reported that the fluvoxamine-induced increase in prefrontal dopamine levels is enhanced by adrenalectomy/castration (which results in circulating neurosteroid deficiency), via combined activation of serotonin1A (5-HT1A) and σ1 receptors. However, the mechanistic details of the interaction between 5-HT1A and σ1 receptors are unknown. OBJECTIVES: Because most neurosteroids have affinity for γ-aminobutyric acid (GABA)A receptors, in the present study, we examined the involvement of GABAA receptors in this process. RESULTS: Adrenalectomy/castration decreased pentobarbital-induced sleeping time in mice, suggesting that it reduced GABAA receptor function. The GABAA receptor antagonist picrotoxin (1 mg/kg) enhanced the fluvoxamine-induced increase in prefrontal dopamine, but not noradrenaline or serotonin, levels in mice, suggesting that picrotoxin mimicked the effect of adrenalectomy/castration. Picrotoxin also potentiated the increase in prefrontal dopamine levels mediated by co-administration of the 5-HT1A receptor agonist osemozotan and the σ1 receptor agonist (+)-SKF-10,047, while it did not affect the co-administration-induced changes in noradrenaline and serotonin levels. Conversely, the GABAA receptor agonist diazepam (1 mg/kg) blocked the effect of adrenalectomy/castration on the fluvoxamine-induced increase in prefrontal dopamine levels. Co-administration of osemozotan and (+)-SKF-10,047 did not affect the expression of the neuronal activity marker c-Fos in the prefrontal cortex, ventral tegmental area, and nucleus accumbens in control mice, while it increased the c-Fos expression only in the prefrontal cortex and ventral tegmental area in picrotoxin-treated mice. CONCLUSIONS: These results suggest that the GABAA receptor plays a key role in mediating the synergistic effects of 5-HT1A and σ1 receptor activation on prefrontal dopamine neurotransmission.
Asunto(s)
Corteza Prefrontal/efectos de los fármacos , Receptor de Serotonina 5-HT1A/metabolismo , Receptores de GABA-A/metabolismo , Receptores sigma/metabolismo , Adrenalectomía , Animales , Antipsicóticos/farmacología , Castración , Diazepam/farmacología , Dioxanos/farmacología , Dioxoles/farmacología , Dopamina/metabolismo , Fluvoxamina/farmacología , Antagonistas del GABA/farmacología , Moduladores del GABA/farmacología , Antagonistas de Receptores de GABA-A/farmacología , Masculino , Ratones , Norepinefrina/metabolismo , Núcleo Accumbens/efectos de los fármacos , Núcleo Accumbens/metabolismo , Orquiectomía , Fenazocina/análogos & derivados , Fenazocina/farmacología , Picrotoxina/farmacología , Corteza Prefrontal/metabolismo , Proteínas Proto-Oncogénicas c-fos/efectos de los fármacos , Proteínas Proto-Oncogénicas c-fos/metabolismo , Receptores de GABA/metabolismo , Serotonina/metabolismo , Agonistas del Receptor de Serotonina 5-HT1/farmacología , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Transmisión Sináptica/efectos de los fármacos , Área Tegmental Ventral/efectos de los fármacos , Área Tegmental Ventral/metabolismo , Ácido gamma-Aminobutírico/metabolismo , Receptor Sigma-1RESUMEN
N-allylnormetazocine (NANM; SKF 10,047) is a benzomorphan opioid that produces psychotomimetic effects. (+)-NANM is the prototypical agonist for the sigma-1 (σ1) receptor, and there is a widespread belief that the hallucinogenic effects of NANM and other benzomorphan derivatives are mediated by interactions with σ1 sites. However, NANM is also an agonist at the κ opioid receptor (KOR) and binds to the PCP site located within the channel pore of the NMDA receptor, interactions that could potentially contribute to the effects of NANM. NMDA receptor antagonists such as phencyclidine (PCP) and ketamine are known to disrupt prepulse inhibition (PPI) of acoustic startle, a measure of sensorimotor gating, in rodents. We recently found that racemic NANM disrupts PPI in rats, but it is not clear whether the effect is mediated by blockade of the NMDA receptor, or alternatively whether interactions with KOR and σ1 receptors are involved. The present studies examined whether NANM and its stereoisomers alter PPI in C57BL/6J mice, and tested whether the effects on PPI are mediated by KOR or σ1 receptors. Racemic NANM produced a dose-dependent disruption of PPI (3-30mg/kg SC). (+)-NANM also disrupted PPI, whereas (-)-NANM was ineffective. Pretreatment with the selective KOR antagonist nor-binaltorphimine (10mg/kg SC) or the selective σ1 antagonist NE-100 (1mg/kg IP) failed to attenuate the reduction in PPI produced by racemic NANM. We also found that the selective KOR agonist (-)-U-50,488H (10-40mg/kg SC) had no effect on PPI. These findings confirm that NANM reduces sensorimotor gating in rodents, and indicate that the effect is mediated by interactions with the PCP receptor and not by activation of KOR or σ1 receptors. This observation is consistent with evidence indicating that the σ1 receptor is not linked to hallucinogenic or psychotomimetic effects.
Asunto(s)
Alucinógenos/farmacología , Fenazocina/análogos & derivados , Inhibición Prepulso/efectos de los fármacos , 3,4-Dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclohexil)-bencenacetamida, (trans)-Isómero/farmacología , Animales , Anisoles/farmacología , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Ratones Endogámicos C57BL , Naltrexona/análogos & derivados , Naltrexona/farmacología , Fenazocina/farmacología , Inhibición Prepulso/fisiología , Propilaminas/farmacología , Receptores Opioides kappa/agonistas , Receptores de Fenciclidina/fisiología , Receptores sigma/agonistas , Reflejo de Sobresalto/efectos de los fármacos , Estereoisomerismo , Receptor Sigma-1RESUMEN
AIMS: Sigma-1 receptors are involved in the pathophysiological process of several neuropsychiatric diseases such as epilepsy, depression. Allosteric modulation represents an important mechanism for receptor functional regulation. In this study, we examined antidepressant activity of the latest identified novel and selective allosteric modulator of sigma-1 receptor 3-methyl-phenyl-2, 3, 4, 5-tetrahydro-1H-benzo[d]azepin-7-ol (SOMCL-668). METHODS AND RESULTS: A single administration of SOMCL-668 decreased the immobility time in the forced swimming test (FST) and tailing suspended test in mice, which were abolished by pretreatment of sigma-1 receptor antagonist BD1047. In the chronic unpredicted mild stress (CUMS) model, chronic application of SOMCL-668 rapidly ameliorated anhedonia-like behavior (within a week), accompanying with the enhanced expression of brain-derived neurotrophic factor (BDNF) and phosphorylation of glycogen synthase kinase 3ß (GSK3ß) (Ser-9) in the hippocampus. SOMCL-668 also rapidly promoted the phosphorylation of GSK3ß (Ser-9) in an allosteric manner in vitro. In the cultured primary neurons, SOMCL-668 enhanced the sigma-1 receptor agonist-induced neurite outgrowth and the secretion of BDNF. CONCLUSION: SOMCL-668, a novel allosteric modulator of sigma-1 receptors, elicits a potent and rapid acting antidepressant effect. The present data provide the first evidence that allosteric modulation of sigma-1 receptors may represent a new approach for antidepressant drug discovery.
Asunto(s)
Antidepresivos/uso terapéutico , Benzazepinas/uso terapéutico , Receptores sigma/metabolismo , Estrés Psicológico/tratamiento farmacológico , Animales , Antidepresivos/farmacología , Antipsicóticos/farmacología , Ansiedad/tratamiento farmacológico , Ansiedad/etiología , Benzazepinas/farmacología , Factor Neurotrófico Derivado del Encéfalo/farmacología , Células Cultivadas , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Embrión de Mamíferos , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Hipocampo/citología , Pérdida de Tono Postural/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/citología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Fenazocina/análogos & derivados , Fenazocina/farmacología , Transducción de Señal/efectos de los fármacos , Estrés Psicológico/complicaciones , Natación/psicología , Factores de Tiempo , Clorhidrato de Venlafaxina/farmacología , Clorhidrato de Venlafaxina/uso terapéutico , Receptor Sigma-1RESUMEN
Sigma-1 receptors (σ-1Rs) are endoplasmic reticulum resident chaperone proteins implicated in many physiological and pathological processes in the CNS. A striking feature of σ-1Rs is their ability to interact and modulate a large number of voltage- and ligand-gated ion channels at the plasma membrane. We have reported previously that agonists for σ-1Rs potentiate NMDA receptor (NMDAR) currents, although the mechanism by which this occurs is still unclear. In this study, we show that in vivo administration of the selective σ-1R agonists (+)-SKF 10,047 [2S-(2α,6α,11R*]-1,2,3,4,5,6-hexahydro-6,11-dimethyl-3-(2-propenyl)-2,6-methano-3-benzazocin-8-ol hydrochloride (N-allylnormetazocine) hydrochloride], PRE-084 (2-morpholin-4-ylethyl 1-phenylcyclohexane-1-carboxylate hydrochloride), and (+)-pentazocine increases the expression of GluN2A and GluN2B subunits, as well as postsynaptic density protein 95 in the rat hippocampus. We also demonstrate that σ-1R activation leads to an increased interaction between GluN2 subunits and σ-1Rs and mediates trafficking of NMDARs to the cell surface. These results suggest that σ-1R may play an important role in NMDAR-mediated functions, such as learning and memory. It also opens new avenues for additional studies into a multitude of pathological conditions in which NMDARs are involved, including schizophrenia, dementia, and stroke.
Asunto(s)
Membrana Celular/metabolismo , Hipocampo/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Receptores sigma/metabolismo , Regulación hacia Arriba/fisiología , Animales , Membrana Celular/efectos de los fármacos , Homólogo 4 de la Proteína Discs Large , Etilenodiaminas/farmacología , Hipocampo/efectos de los fármacos , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Ratones Noqueados , Morfolinas/farmacología , Pentazocina/farmacología , Fenazocina/análogos & derivados , Fenazocina/farmacología , Piperazinas/farmacología , Transporte de Proteínas/efectos de los fármacos , Transporte de Proteínas/genética , Ratas , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/genética , Receptores sigma/agonistas , Receptores sigma/antagonistas & inhibidores , Receptores sigma/genética , Fracciones Subcelulares/efectos de los fármacos , Fracciones Subcelulares/metabolismo , Factores de Tiempo , Regulación hacia Arriba/efectos de los fármacos , Receptor Sigma-1RESUMEN
Serotonin (5-HT)1A and σ1 receptors have been implicated in psychiatric disorders. We previously found that combined 5-HT reuptake inhibition and σ1 receptor activation has a synergistic effect on prefrontal dopaminergic transmission in adrenalectomized/castrated mice lacking circulating steroid hormones. In the present study, we examined the mechanisms underlying this neurochemical synergism. Systemic administration of fluvoxamine, a selective 5-HT reuptake inhibitor with agonistic activity towards the σ1 receptor, increased prefrontal dopamine (DA) levels, and adrenalectomy/castration potentiated this fluvoxamine-induced increase in DA. This enhancement of DA release was blocked by WAY100635 (a 5-HT1A receptor antagonist), but not by ritanserin (a 5-HT2 receptor antagonist), azasetron (a 5-HT3 receptor antagonist) or SB269970 (a 5-HT7 receptor antagonist). Individually, osemozotan (a 5-HT1A receptor agonist) and (+)-SKF-10,047 (a σ1 receptor agonist) did not alter prefrontal monoamine levels in adrenalectomized/castrated and sham-operated mice differentially. In contrast, co-administration of these drugs increased prefrontal DA levels to a greater extent in adrenalectomized/castrated mice than in sham-operated animals. Furthermore, co-administration of osemozotan and (+)-SKF-10,047 increased expression of the neuronal activity marker c-Fos in the ventral tegmental area of adrenalectomized/castrated mice, but not in sham-operated animals. These findings suggest that combined activation of 5-HT1A and σ1 receptors has a synergistic effect on prefrontal dopaminergic transmission under circulating steroid deficiency, and that this interaction may play an important role in the regulation of the prefrontal DA system.
Asunto(s)
Dopamina/metabolismo , Corteza Prefrontal/metabolismo , Receptor de Serotonina 5-HT1A/metabolismo , Receptores sigma/metabolismo , Esteroides/sangre , Adrenalectomía , Animales , Castración , Sinergismo Farmacológico , Masculino , Ratones , Ratones Endogámicos , Fenazocina/análogos & derivados , Fenazocina/farmacología , Corteza Prefrontal/efectos de los fármacos , Proteínas Proto-Oncogénicas c-fos/metabolismo , Receptores sigma/agonistas , Serotoninérgicos/farmacología , Área Tegmental Ventral/efectos de los fármacos , Área Tegmental Ventral/metabolismo , Receptor Sigma-1RESUMEN
We used conscious tethered Sprague-Dawley rats to evaluate the cardiovascular effects of four sigma-1 (σ1 ) agonists and five antagonists, given alone or in combination. All drugs were administered as a single intraperitoneal dose. The agonists were given at doses reported as efficacious in rodent cognition models, while the antagonists were administered at doses neutralizing agonist effects in vivo. Systolic blood pressure (SBP) and heart rate (HR) were continuously recorded for 20 min before and 60 min postadministration. Immediately after injection, a sudden, transitory increase in HR and SBP was noted in all animals, because of the stress induced by handling. For both parameters, a peak value (ΔHRmax and ΔSBPmax ) and an area under the curve of changes from baseline over the period 5-20 min postinjection (ΔHR_AUC5-20 min and ΔSBP_AUC5-20 min ) were calculated. Three of the four σ1 agonists (SKF-10,047, dehydroepiandrosterone (DHEAS), Compound 14) significantly reduced ΔHR_AUC5-20 min value without changing ΔHRmax , while the fourth one, SA-4503, had no significant effect. None of the antagonists (haloperidol, rimcazole, NE-100, and BD1047) reduced, and even one (progesterone) enhanced the stress-induced effects on HR. No changes in SBP were noted with any compound. When the antagonist NE-100 was administered just before SKF-10,047, it completely reversed the inhibitory effects of the σ1 agonist on HR increase. In conclusion, we demonstrated for the first time the involvement of σ1 receptors in the regulation of handling-induced tachycardia in the conscious rat. Although additional investigations are needed to fully understand this role, it might offer new therapeutic perspectives to σ1 ligands in the cardiovascular sphere.
Asunto(s)
Receptores sigma/antagonistas & inhibidores , Taquicardia/tratamiento farmacológico , Animales , Anisoles/farmacología , Presión Sanguínea/efectos de los fármacos , Estado de Conciencia/efectos de los fármacos , Diazepam/farmacología , Frecuencia Cardíaca/efectos de los fármacos , Ligandos , Masculino , Fenazocina/análogos & derivados , Fenazocina/farmacología , Propilaminas/farmacología , Ratas , Ratas Sprague-Dawley , Receptores sigma/agonistas , Taquicardia/metabolismo , Receptor Sigma-1RESUMEN
Sigma-1 receptors (σ-1rs) exert neuroprotective effects on retinal ganglion cells (RGCs) both in vivo and in vitro. This receptor has unique properties through its actions on several voltage-gated and ligand-gated channels. The purpose of this study was to investigate the role that σ-1rs play in regulating cell calcium dynamics through activated L-type Voltage Gated Calcium Channels (L-type VGCCs) in purified RGCs. RGCs were isolated from P3-P7 Sprague-Dawley rats and purified by sequential immunopanning using a Thy1.1 antibody. Calcium imaging was used to measure changes in intracellular calcium after depolarizing the cells with potassium chloride (KCl) in the presence or absence of two σ-1r agonists [(+)-SKF10047 and (+)-Pentazocine], one σ-1r antagonist (BD1047), and one L-type VGCC antagonist (Verapamil). Finally, co-localization studies were completed to assess the proximity of σ-1r with L-type VGCCs in purified RGCs. VGCCs were activated using KCl (20 mM). Pre-treatment with a known L-type VGCC blocker demonstrated a 57% decrease of calcium ion influx through activated VGCCs. Calcium imaging results also demonstrated that σ-1r agonists, (+)-N-allylnormetazocine hydrochloride [(+)-SKF10047] and (+)-Pentazocine, inhibited calcium ion influx through activated VGCCs. Antagonist treatment using BD1047 demonstrated a potentiation of calcium ion influx through activated VGCCs and abolished all inhibitory effects of the σ-1r agonists on VGCCs, implying that these ligands were acting through the σ-1r. An L-type VGCC blocker (Verapamil) also inhibited KCl activated VGCCs and when combined with the σ-1r agonists there was not a further decline in calcium entry suggesting similar mechanisms. Lastly, co-localization studies demonstrated that σ-1rs and L-type VGCCs are co-localized in purified RGCs. Taken together, these results indicated that σ-1r agonists can inhibit KCl induced calcium ion influx through activated L-type VGCCs in purified RGCs. This is the first report of attenuation of L-type VGCC signaling through the activation of σ-1rs in purified RGCs. The ability of σ-1rs to co-localize with L-type VGCCs in purified RGCs implied that these two proteins are in close proximity to each other and that such interactions regulate L-type VGCCs.
Asunto(s)
Canales de Calcio Tipo L/metabolismo , Calcio/metabolismo , Receptores sigma/metabolismo , Células Ganglionares de la Retina/efectos de los fármacos , Animales , Animales Recién Nacidos , Western Blotting , Bloqueadores de los Canales de Calcio/farmacología , Señalización del Calcio/fisiología , Células Cultivadas , Etilenodiaminas/farmacología , Técnica del Anticuerpo Fluorescente Indirecta , Fura-2/análogos & derivados , Fura-2/metabolismo , Microscopía Fluorescente , Pentazocina/farmacología , Fenazocina/análogos & derivados , Fenazocina/farmacología , Ratas , Ratas Sprague-Dawley , Receptores sigma/agonistas , Receptores sigma/antagonistas & inhibidores , Células Ganglionares de la Retina/metabolismo , Verapamilo/farmacología , Receptor Sigma-1RESUMEN
(+)-SKF 10047 (N-allyl-normetazocine) is a prototypic and specific sigma-1 receptor agonist that has been used extensively to study the function of sigma-1 receptors. (+)-SKF 10047 inhibits K(+), Na(+) and Ca2+ channels via sigma-1 receptor activation. We found that (+)-SKF 10047 inhibited Na(V)1.2 and Na(V)1.4 channels independently of sigma-1 receptor activation. (+)-SKF 10047 equally inhibited Na(V)1.2/1.4 channel currents in HEK293T cells with abundant sigma-1 receptor expression and in COS-7 cells, which barely express sigma-1 receptors. The sigma-1 receptor antagonists BD 1063,BD 1047 and NE-100 did not block the inhibitory effects of (+)-SKF-10047. Blocking of the PKA, PKC and G-protein pathways did not affect (+)-SKF 10047 inhibition of Na(V)1.2 channel currents. The sigma-1 receptor agonists Dextromethorphan (DM) and 1,3-di-o-tolyl-guanidine (DTG) also inhibited Na(V)1.2 currents through a sigma-1 receptor-independent pathway. The (+)-SKF 10047 inhibition of Na(V)1.2 currents was use- and frequency-dependent. Point mutations demonstrated the importance of Phe(1764) and Tyr(1771) in the IV-segment 6 domain of the Na(V)1.2 channel and Phe(1579) in the Na(V)1.4 channel for (+)-SKF 10047 inhibition. In conclusion, our results suggest that sigma-1 receptor agonists directly inhibit Na(V)1.2/1.4 channels and that these interactions should be given special attention for future sigma-1 receptor function studies.
Asunto(s)
Dextrometorfano/farmacología , Guanidinas/farmacología , Proteínas Musculares/antagonistas & inhibidores , Canal de Sodio Activado por Voltaje NAV1.2/metabolismo , Fenazocina/análogos & derivados , Receptores sigma/agonistas , Animales , Células COS , Chlorocebus aethiops , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Proteínas de Unión al GTP/metabolismo , Células HEK293 , Humanos , Activación del Canal Iónico/efectos de los fármacos , Lidocaína/farmacología , Proteínas Musculares/metabolismo , Mutagénesis Sitio-Dirigida , Proteínas Mutantes/metabolismo , Mutación/genética , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Fenazocina/farmacología , Proteína Quinasa C/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Ratas , Receptores sigma/metabolismo , Transducción de Señal/efectos de los fármacos , Canales de Sodio/metabolismo , Transfección , Receptor Sigma-1RESUMEN
Straub tail reaction (STR) was observed in male ddY mice after simultaneous administration with BMY 14802 (a non-specific σ receptor antagonist) and methamphetamine (METH). The intensity and duration of STR depended on the dose of BMY 14802. The tail reaction was inhibited completely by (+)-SKF 10,047 (a putative σ(1) receptor agonist) and partially by PB 28 (a putative σ(2) receptor agonist). The STR was mimicked in mice treated with BD 1047 (a putative σ(1) receptor antagonist), but not SM-21, a putative σ(2) receptor antagonist, in combination with METH. STR evoked with BD 1047 plus METH was inhibited by (+)-SKF 10,047. STR induced by BMY 14802 and METH was abolished by naloxone (a relatively non-selective opioid receptor antagonist) or U-50,488H (a selective κ-agonist), suggesting that the STR may be mediated by activation of opioid receptor system.
Asunto(s)
Estimulantes del Sistema Nervioso Central/farmacología , Metanfetamina/farmacología , Antagonistas de Narcóticos/farmacología , Pirimidinas/farmacología , Reflejo/efectos de los fármacos , 3,4-Dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclohexil)-bencenacetamida, (trans)-Isómero/farmacología , Analgésicos no Narcóticos/farmacología , Animales , Antipsicóticos , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Combinación de Medicamentos , Masculino , Ratones , Ratones Endogámicos , Morfina/farmacología , Naloxona/farmacología , Narcóticos/farmacología , Fenazocina/análogos & derivados , Fenazocina/farmacología , Receptores Opioides delta/agonistas , Receptores Opioides delta/antagonistas & inhibidores , Cola (estructura animal)/efectos de los fármacos , Factores de TiempoRESUMEN
Treatment with sigma1 receptor (Sigma1) ligands can inhibit cell proliferation in vitro and tumor growth in vivo. However, the cellular pathways engaged in response to Sigma1 ligand treatment that contribute to these outcomes remain largely undefined. Here, we show that treatment with putative antagonists of Sigma1 decreases cell mass. This effect corresponds with repressed cap-dependent translation initiation in multiple breast and prostate cancer cell lines. Sigma1 antagonist treatment suppresses phosphorylation of translational regulator proteins p70S6K, S6, and 4E-BP1. RNAi-mediated knockdown of Sigma1 also results in translational repression, consistent with the effects of antagonist treatment. Sigma1 antagonist mediated translational repression and decreased cell size are both reversible. Together, these data reveal a role for Sigma1 in tumor cell protein synthesis, and demonstrate that small molecule Sigma1 ligands can be used as modulators of protein translation.
Asunto(s)
Proliferación Celular/efectos de los fármacos , Neoplasias/metabolismo , Neoplasias/patología , Receptores sigma/antagonistas & inhibidores , Línea Celular Tumoral , Tamaño de la Célula/efectos de los fármacos , Haloperidol/farmacología , Humanos , Ligandos , Morfolinas/farmacología , Fenazocina/análogos & derivados , Fenazocina/farmacología , Biosíntesis de Proteínas/efectos de los fármacos , Proteínas de Unión a Caperuzas de ARN/metabolismo , Receptor Sigma-1RESUMEN
σ-1 Receptors are expressed in the brain, and their activation has been shown to prevent neuronal death associated with glutamate toxicity. This study investigates the possible mechanism and effect of [2S-(2α,6α,11R*]-1,2,3,4,5,6-hexahydro-6,11-dimethyl-3-(2-propenyl)-2,6-methano-3-benzazocin-8-ol (SKF10047), a σ-1 receptor agonist, on endogenous glutamate release in the nerve terminals of rat cerebral cortex. Results show that SKF10047 inhibited the release of glutamate evoked by the K⺠channel blocker 4-aminopyridine (4-AP), and the σ-1 receptor antagonist N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino)ethylamine (BD1047) blocked this phenomenon. The effects of SKF10047 on the evoked glutamate release were prevented by the chelating extracellular Ca²âºions and the vesicular transporter inhibitor bafilomycin A1. However, the glutamate transporter inhibitor DL-threo-ß-benzyl-oxyaspartate did not have any effect on the action of SKF10047. SKF10047 decreased the depolarization-induced increase in the cytosolic free Ca²âº concentration ([Ca²âº](C)), but did not alter 4-AP-mediated depolarization. Furthermore, the effects of SKF10047 on evoked glutamate release were prevented by blocking the Ca(v)2.2 (N-type) and Ca(v)2.1 (P/Q-type) channels, but not by blocking the ryanodine receptors or the mitochondrial Naâº/Ca²âº exchange. In addition, conventional protein kinase C (PKC) inhibitors abolished the SKF10047 effect on 4-AP-evoked glutamate release. Western blot analyses showed that SKF10047 decreased the 4-AP-induced phosphorylation of PKC and PKCα. These results show that σ-1 receptor activation inhibits glutamate release from rat cortical nerve terminals. This effect is linked to a decrease in [Ca²âº](C) caused by Ca²âº entry through presynaptic voltage-dependent Ca²âº channels and the suppression of the PKC signaling cascade.
Asunto(s)
Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/metabolismo , Ácido Glutámico/metabolismo , Terminaciones Nerviosas/efectos de los fármacos , Terminaciones Nerviosas/metabolismo , Fenazocina/análogos & derivados , Receptores sigma/agonistas , Receptores sigma/metabolismo , 4-Aminopiridina/farmacología , Sistema de Transporte de Aminoácidos X-AG/antagonistas & inhibidores , Animales , Ácido Aspártico/farmacología , Calcio/metabolismo , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio/metabolismo , Canales de Calcio Tipo N/metabolismo , Citosol/efectos de los fármacos , Citosol/metabolismo , Macrólidos/farmacología , Masculino , Potenciales de la Membrana/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Fenazocina/farmacología , Fosforilación/efectos de los fármacos , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio/metabolismo , Proteína Quinasa C/antagonistas & inhibidores , Ratas , Ratas Sprague-Dawley , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Intercambiador de Sodio-Calcio/metabolismo , Proteínas de Transporte Vesicular/antagonistas & inhibidores , Proteínas de Transporte Vesicular/metabolismo , Receptor Sigma-1RESUMEN
The present study was undertaken to identify possible similarities between the effects of kappa-opioid receptor agonist, N-methyl-D-aspartate-receptor antagonist, and sigma receptor agonist on the discriminative stimulus effects of U-50488H, and the possible involvement of sigma receptors in the discriminative stimulus and aversive effects of U-50488H. The kappa-opioid receptor agonist U-50488H produced significant place aversion as measured by the conditioned place preference procedure, and this effect was completely abolished by treatment with the putative sigma-1 receptor antagonist NE-100. In addition, phencyclidine (+)-SKF-10047 and (+)-pentazocine, which are sigma receptor agonists, generalized to the discriminative stimulus effects of U-50488H in rats that had been trained to discriminate between U-50488H (3.0 mg/kg) and saline. Furthermore, NE-100 significantly attenuated the discriminative stimulus effects of U-50488H and the U-50488H-like discriminative stimulus effects of phencyclidine. These results suggest that the sigma-1 receptor is responsible for both the discriminative stimulus effects and aversive effects of U-50488H.
Asunto(s)
3,4-Dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclohexil)-bencenacetamida, (trans)-Isómero/farmacología , Discriminación en Psicología/efectos de los fármacos , Receptores Opioides kappa/antagonistas & inhibidores , Receptores sigma/antagonistas & inhibidores , Animales , Anisoles/farmacología , Reacción de Prevención/efectos de los fármacos , Condicionamiento Psicológico/efectos de los fármacos , Aprendizaje Discriminativo/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Masculino , Antagonistas de Narcóticos/farmacología , Pentazocina/farmacología , Fenazocina/análogos & derivados , Fenazocina/farmacología , Fenciclidina/farmacología , Propilaminas/farmacología , Ratas , Ratas Endogámicas F344 , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Receptor Sigma-1RESUMEN
RATIONALE: Fluvoxamine, a selective serotonin (5-HT) reuptake inhibitor (SSRI) and an agonist for the σ(1) receptors, increases extracellular monoamines in the prefrontal cortex, but it is not known whether the σ(1) receptor is involved in the neurochemical effect of fluvoxamine. OBJECTIVES: In view of the fact that circulating steroids exert a tonic modulatory effect on σ(1) receptor-mediated effects, the present study examines the effects of fluvoxamine on prefrontal extracellular monoamine levels in adrenalectomized/castrated mice lacking the peripheral sources of steroids. RESULTS: Fluvoxamine-induced increases in the extracellular levels of dopamine (DA), but not of 5-HT and noradrenaline, were significantly higher in adrenalectomized/castrated than in sham-operated mice, and this effect was blocked by BD1047, a selective σ(1) receptor antagonist. In contrast, the effects of paroxetine, an SSRI without affinity for the σ(1) receptors, and (+)-SKF-10,047, a selective σ(1) receptor agonist, on the extracellular monoamine levels did not differ between adrenalectomized/castrated and sham-operated mice, while the increase in extracellular DA levels induced by co-administration of these drugs was higher in adrenalectomized/castrated than in the control mice. Moreover, fluvoxamine increased c-Fos expression, a marker of neuronal activity, in the prefrontal cortex of adrenalectomized/castrated mice, and this effect was blocked by BD1047. The similar increase in c-Fos expression was observed by co-administration of paroxetine and (+)-SKF-10,047. CONCLUSIONS: These findings suggest that fluvoxamine enhances prefrontal dopaminergic neurotransmission via both 5-HT reuptake inhibition and σ(1) receptor activation under the circulating neuroactive steroid-deficient conditions.