RESUMEN
Neuroprotective effects of Sigma-1 receptor (S1R) ligands have been observed in multiple animal models of neurodegenerative diseases. Traumatic brain injury (TBI)-related neurodegeneration can induce long-lasting physical, cognitive, and behavioral disabilities. The aim of our study was to evaluate the role of S1R in the development of neurological deficits after TBI. Adult male wild-type CD-1 (WT) and S1R knockout (S1R-/-) mice were subjected to lateral fluid percussion injury, and behavioral and histological outcomes were assessed for up to 12 months postinjury. Neurological deficits and motor coordination impairment were less pronounced in S1R-/- mice with TBI than in WT mice with TBI 24 h after injury. TBI-induced short-term memory impairments were present in WT but not S1R-/- mice 7 months after injury. Compared to WT animals, S1R-/- mice exhibited better motor coordination and less pronounced despair behavior for up to 12 months postinjury. TBI induced astrocyte activation in the cortex of WT but not S1R-/- mice. S1R-/- mice presented a significantly reduced GFAP expression in Bergmann glial cells in the molecular layer of the cerebellum compared to WT mice. Our findings suggest that S1R deficiency reduces TBI-induced motor coordination impairments by reducing GFAP expression in Bergmann glial cells in the cerebellum.
Asunto(s)
Lesiones Traumáticas del Encéfalo/metabolismo , Cerebelo/metabolismo , Proteína Ácida Fibrilar de la Glía/metabolismo , Neuroglía/metabolismo , Receptores sigma/metabolismo , Animales , Astrocitos , Modelos Animales de Enfermedad , Hipocampo/metabolismo , Masculino , Ratones , Ratones Noqueados , Enfermedades Neurodegenerativas/metabolismo , Fármacos Neuroprotectores/metabolismo , Receptor Sigma-1RESUMEN
There is a growing body of evidence demonstrating the significant involvement of the sigma-1 chaperone protein in the modulation of seizures. Several sigma-1 receptor (Sig1R) ligands have been demonstrated to regulate the seizure threshold in acute and chronic seizure models. However, the mechanism by which Sig1R modulates the excitatory and inhibitory pathways in the brain has not been elucidated. The aim of this study was to compare the susceptibility to seizures of wild type (WT) and Sig1R knockout (Sig1R-/-) mice in intravenous pentylenetetrazol (PTZ) and (+)-bicuculline (BIC) infusion-induced acute seizure and Sig1R antagonist NE-100-induced seizure models. To determine possible molecular mechanisms, we used quantitative PCR, Western blotting and immunohistochemistry to assess the possible involvement of several seizure-related genes and proteins. Peripheral tissue contractile response of WT and Sig1R-/- mice was studied in an isolated vasa deferentia model. The most important finding was the significantly decreased expression of the R2 subunit of the GABA-B receptor in the hippocampus and habenula of Sig1R-/- mice. Our results demonstrated that Sig1R-/- mice have decreased thresholds for PTZ- and BIC-induced tonic seizures. In the NE-100-induced seizure model, Sig1R-/- animals demonstrated lower seizure scores, shorter durations and increased latency times of seizures compared to WT mice. Sig1R-independent activities of NE-100 included downregulation of the gene expression of iNOS and GABA-A γ2 and inhibition of KCl-induced depolarization in both WT and Sig1R-/- animals. In conclusion, the results of this study indicate that the lack of Sig1R resulted in decreased expression of the R2 subunit of the GABA-B receptor and increased susceptibility to seizures. Our results confirm that Sig1R is a significant molecular target for seizure modulation and warrants further investigation for the development of novel anti-seizure drugs.
Asunto(s)
Convulsivantes/toxicidad , Habénula/metabolismo , Hipocampo/metabolismo , Receptores de GABA-B/genética , Receptores sigma/genética , Convulsiones/genética , Animales , Anisoles/toxicidad , Bicuculina/toxicidad , Expresión Génica/efectos de los fármacos , Expresión Génica/genética , Predisposición Genética a la Enfermedad , Habénula/efectos de los fármacos , Hipocampo/efectos de los fármacos , Ratones , Ratones Noqueados , Óxido Nítrico Sintasa de Tipo II/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo II/genética , Pentilenotetrazol/toxicidad , Propilaminas/toxicidad , Receptores de GABA-A/efectos de los fármacos , Receptores de GABA-A/genética , Receptores de GABA-B/metabolismo , Convulsiones/inducido químicamente , Receptor Sigma-1RESUMEN
Sigma-1 receptor (Sig1R) is a ligand-regulated protein which, since its discovery, has been widely studied as a novel target to treat neurological disorders, including seizures. However, the roles and mechanisms of Sig1R in the regulation of seizures are not fully understood. The aim of the present study was to test and compare effects of often used selective Sig1R ligands in models of experimentally induced seizures. The anti-seizure activities and interactions of selective Sig1R agonist PRE-084, selective Sig1R antagonist NE-100 and novel positive allosteric Sig1R modulator E1R were evaluated in pentylenetetrazol (PTZ) and (+)-bicuculline (BIC)-induced seizure models in mice. Sig1R antagonist NE-100 at a dose of 25mg/kg demonstrated pro-convulsive activity on PTZ-induced seizures. Agonist PRE-084 did not change the thresholds of chemoconvulsant-induced seizures. Positive allosteric modulator E1R at a dose of 50mg/kg showed anti-convulsive effects on PTZ- and BIC-induced clonic and tonic seizures. The anti-seizure activity of E1R was blocked by NE-100. Surprisingly, NE-100 at a dose of 50mg/kg induced convulsions, but E1R significantly alleviated the convulsive behaviour induced by NE-100. In conclusion, the selective Sig1R antagonist NE-100 induced seizures that could be partially attenuated by positive allosteric Sig1R modulator. Our results confirm that Sig1R could be a novel molecular target for new anti-convulsive drugs.
Asunto(s)
Anticonvulsivantes/farmacología , Convulsivantes/farmacología , Receptores sigma/agonistas , Receptores sigma/antagonistas & inhibidores , Convulsiones/inducido químicamente , Convulsiones/tratamiento farmacológico , Acetamidas/farmacología , Análisis de Varianza , Animales , Anisoles/farmacología , Bicuculina , Masculino , Ratones , Morfolinas/farmacología , Pentilenotetrazol , Propilaminas/farmacología , Pirrolidinonas/farmacología , Receptores sigma/metabolismo , Convulsiones/metabolismo , Análisis de Supervivencia , Receptor Sigma-1RESUMEN
Anti-ischaemic drug mildronate suppresses fatty acid metabolism and increases glucose utilization in myocardium. It was proposed that it could produce a favourable effect on metabolic parameters and glucose transport in diabetic animals. Rats with streptozotocin diabetes mellitus were treated with mildronate (100 mg/kg daily, per os, 6 weeks). Therapeutic effect of mildronate was monitored by measuring animal weight, concentrations of blood glucose, insulin, blood triglycerides, free fatty acids, blood ketone bodies and cholesterol, glycated haemoglobin per cent (HbA1c%) and glucose tolerance. GLUT1 mRNA and protein expression in kidneys, heart, liver and muscles were studied by means of real time RT-PCR and immunohistochemistry correspondingly. In the streptozotocin + mildronate group, mildronate treatment caused a significant decrease in mean blood glucose, cholesterol, free fatty acid and HbA1c concentrations and improved glucose tolerance. Induction of streptozotocin diabetes mellitus provoked increase of both GLUT1 gene and protein expression in kidneys, heart and muscle, mildronate treatment produced normalization of the GLUT1 expression levels. In the liver a similar effect was observed for GLUT1 protein expression, while GLUT1 gene expression was increased by mildronate. Mildronate produces therapeutic effect in streptozotocin diabetes model. Mildronate normalizes the GLUT1 expression up-regulated by streptozotocin diabetes mellitus in kidneys, heart, muscle and liver. Copyright © 2011 John Wiley & Sons, Ltd.
Asunto(s)
Glucemia/metabolismo , Diabetes Mellitus Experimental/tratamiento farmacológico , Transportador de Glucosa de Tipo 1/metabolismo , Hipoglucemiantes/farmacología , Metilhidrazinas/farmacología , ARN Mensajero/metabolismo , Estreptozocina/farmacología , Animales , Glucemia/efectos de los fármacos , Tamaño Corporal/efectos de los fármacos , Diabetes Mellitus/tratamiento farmacológico , Ácidos Grasos/sangre , Ácidos Grasos/metabolismo , Prueba de Tolerancia a la Glucosa , Transportador de Glucosa de Tipo 1/sangre , Transportador de Glucosa de Tipo 1/efectos de los fármacos , Hemoglobina Glucada/efectos de los fármacos , Hemoglobina Glucada/metabolismo , Insulina/sangre , Insulina/metabolismo , Metilhidrazinas/uso terapéutico , ARN Mensajero/efectos de los fármacos , Ratas , Ratas Wistar , Estreptozocina/efectos adversos , Triglicéridos/sangre , Triglicéridos/metabolismoRESUMEN
CONTEXT: Metformin improves hyperglycaemia via mechanisms which include activation of AMP-activated protein kinase (AMPK). Recent findings indicate that some metabolic actions of metformin occur also by AMPK-independent mechanisms. OBJECTIVE: To study the action of metformin on expression of GLUT1 glucose transporter in rat streptozotocin model of diabetes mellitus. MATERIALS AND METHODS: Streptozotocin-induced rats were treated with metformin while monitoring parameters of carbohydrate and lipid metabolism. GLUT1 mRNA and protein expression in kidneys, heart, liver and muscles were studied by means of real time quantitative RT-PCR and immunohistochemistry correspondingly. RESULTS: Metformin treatment decreased glucose concentration, glycated haemoglobin % and improved glucose tolerance. Streptozotocin diabetes provoked increase of both GLUT1 gene and protein expression in kidneys, metformin treatment produced normalization of the GLUT1 expression levels. In the liver, diabetes triggered an increase in GLUT1 protein expression, which was normalized by metformin. CONCLUSION: Metformin is prospective for treatment of diabetic nephropathy.
Asunto(s)
Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Transportador de Glucosa de Tipo 1/biosíntesis , Transportador de Glucosa de Tipo 1/genética , Hipoglucemiantes/farmacología , Metformina/farmacología , Animales , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/patología , Modelos Animales de Enfermedad , Glucosa/metabolismo , Prueba de Tolerancia a la Glucosa , Hemoglobina Glucada/metabolismo , Hipoglucemiantes/uso terapéutico , Masculino , Metformina/uso terapéutico , Ratas , Ratas WistarRESUMEN
Production of nitric oxide was measured in lipopolysaccharide-treated rats (10 mg/kg, 4 hr) using the electron paramagnetic resonance method. As compared to the control animals, the nitric oxide level in liver of lipopolysaccharide-treated rats increased from 27.6+/-4.7 to 1485+/-129 ng/g tissue, in heart from 4.8+/-0.7 to 271+/-26 ng/g tissue, in blood from 33.6+/-12.4 to 638+/-136 ng/g tissue, in kidney from 3.3+/-0.5 to 356+/-31 ng/g tissue, in brain cortex from 46.0+/-3.4 to 227+/-27 ng/g tissue, in cerebellum from 27.7+/-2.6 to 218+/-30 ng/g tissue, and in testes from 13.8+/-1.1 to 86+/-8 ng/g tissue. Administration of the antiischaemic drug, mildronate (120 mg/kg) caused a significant twofold decrease of the nitric oxide level in brain cortex and cerebellum 1 hr after drug administration. Its natural analogue gamma-butyrobetaine (30 mg/kg) triggered a twofold decrease of the nitric oxide concentration in all studied tissues 30 min. after the administration. Nitric oxide reached the initial level 2 hr later. Neither mildronate nor gamma-butyrobetaine could inhibit the inducible nitric oxide synthase in vitro. Analogues of gamma-butyrobetaine appear to be prospective drugs for the treatment of circulatory complications of sepsis.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Betaína/análogos & derivados , Betaína/farmacología , Carnitina , Lipopolisacáridos , Metilhidrazinas/farmacología , Óxido Nítrico/biosíntesis , Sepsis/metabolismo , Animales , Masculino , Ratas , Ratas WistarRESUMEN
A TG dinucleotide repeat was identified in intron 6 of the human proteasome core particle PROS-27K (IOTA, PSMA6) gene. We present data on the length polymorphism of this repeat in 120 individuals from Latvia and 197 individuals from Finland. A combination of PCR and fluorescent gel electrophoresis was utilized to type the polymorphism. Twelve alleles were observed, varying in length from 10 to 23 TG repeats. Similar allele frequencies were observed in Latvian and Finnish subjects, with 17 and 20 repeats being the most frequent in both populations. We suggest that this TG dinucleotide repeat could be utilized as a prospective marker for genetic linkage and association studies of common diseases.