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1.
Pediatr Cardiol ; 45(5): 1048-1054, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38509207

RESUMEN

The purpose of this paper was to unravel the clinical effect analysis of different doses of creatine phosphate sodium (CPS) combined with immunoglobulin in the treatment of pediatric viral myocarditis (VMC). One hundred and twenty children with VMC were recruited and randomized into three groups (40 patients each). Group I received 1.0 g of CPS dissolved in 100 mL of 5% glucose injection intravenously 1 time/day; group II received 1.25 g of CPS dissolved in 125 mL of 5% glucose injection intravenously 1 time/day; group III received 1.5 g of CPS dissolved in 150 mL of 5% glucose injection intravenously 1 time/day; then all three groups were treated with combined use of immunoglobulin (300-400 mg/day) intravenously once a day; and all three groups were treated for 14 days. The clinical efficacy, cardiac function, serum inflammatory factor levels, immune function, and the occurrence of drug toxicity and adverse effects of the children in the three groups were compared after 14 days of treatment. All three groups achieved better therapeutic effects after treatment, in which the effective rate of the Group II and Group III was notably higher versus the Group I. Lower levels of cTnI, CK-MB, LDH, AST, IL-18, IL-6, IFN-γ, and LVEDD and higher CD3+, CD4+, and CD4+/CD8+, FS, and LVEF values were noted in the Group II and Group III versus the Group I, and the results were more pronounced in the high-dose group. The liver and kidney functions of the children in the three groups before and after treatment did not show any significant changes and the incidence of adverse reactions during the treatment period was low in all three groups. Children with VMC can be treated with high-dose CPS in combination with immunoglobulin, which can improve their cardiac function and immune function and reduce the inflammatory response with good overall therapeutic efficacy and fewer adverse effects.


Asunto(s)
Miocarditis , Fosfocreatina , Humanos , Miocarditis/tratamiento farmacológico , Masculino , Femenino , Niño , Preescolar , Resultado del Tratamiento , Quimioterapia Combinada , Relación Dosis-Respuesta a Droga , Virosis/tratamiento farmacológico , Inmunoglobulinas/administración & dosificación , Inmunoglobulinas/uso terapéutico
2.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 37(9): 1009-1013, 2020 Sep 10.
Artículo en Zh | MEDLINE | ID: mdl-32820518

RESUMEN

OBJECTIVE: To analyze the clinical and molecular characteristics of a child with very long chain acyl-CoA dehydrogenase deficiency (VLCADD). METHODS: Peripheral blood sample of the patient was collected for the extraction of genomic DNA. Next generation sequencing (NGS) was carried out for the proband. Suspected mutations were validated by Sanger sequencing. RESULTS: The patient, a 12-month-old girl, was admitted for diarrhea, vomiting, fever, poor spirit and decreased blood pressure. During the course of the disease, she also manifested hypertrophic cardiomyopathy, cardiogenic shock, elevated myocardial enzyme kinase, fever and metabolic acidosis, and had died after three days due to ventricular tachycardia and respiratory failure. Genetic testing showed that she has carried heterozygous mutations of of the ACADVL gene, namely c.664G>A (exon 8) and c.1056_1057del (exon 10). Blood screening for metabolic genetic diseases showed increased C12, C14, C16, C18, C14:1, C14:2, C16:1, C4/C3 and C8/C3, accompanied with decreased C0, C0/C16 and C8/C10. VLCADD and secondary carnitine deficiency could not be excluded, which was in keeping with the result of genetic testing. CONCLUSION: The child was diagnosed with VLCADD, which may be attributed to the compound heterozygous c.664G>A and c.1056_1057del variants of the ACADVL gene.


Asunto(s)
Acil-CoA Deshidrogenasa de Cadena Larga/deficiencia , Síndromes Congénitos de Insuficiencia de la Médula Ósea/genética , Errores Innatos del Metabolismo Lipídico/genética , Enfermedades Mitocondriales/genética , Enfermedades Musculares/genética , Acil-CoA Deshidrogenasa de Cadena Larga/genética , Femenino , Pruebas Genéticas , Humanos , Lactante
3.
Yi Chuan ; 35(7): 830-8, 2013 Jul.
Artículo en Zh | MEDLINE | ID: mdl-23853353

RESUMEN

Lipoprotein lipase (LPL) is an essential enzyme in the lipid metabolism, and proper regulation of LPL is important for controlling the delivery of lipid nutrients to tissues. Recent studies have identified glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1(GPIHBP1) as the important regulation factor of LPL that serves as a binding platform for lipolysis on the vascular lumen and an endothelial cell transporter transporting LPL from the interstitial spaces to the capillary lumen. In addition, several other regulation factors of LPL have also been identified including microRNAs, SorLA (Sortilin-related receptor with A-type repeats), and apolipoproteins that are potentially important for regulating LPL activity. These discoveries provide new directions for understanding basic mechanisms of lipolysis and hyperlipidemia. In this update, we focused on summarizing recent progresses on GPIHBP1, the endothelial cell LPL transporter. We also highlighted the recent progresses on several other regulation factors of LPL that are relevant to the regulation of LPLactivity.


Asunto(s)
Regulación de la Expresión Génica , Lipoproteína Lipasa/genética , Lipoproteína Lipasa/metabolismo , Animales , Humanos , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Receptores de Lipoproteína/genética , Receptores de Lipoproteína/metabolismo
4.
Can J Physiol Pharmacol ; 90(4): 463-71, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22462492

RESUMEN

Atherosclerosis is an important underlying pathology of cardiovascular diseases. The aim of this study was to observe the expression of salusin-ß, a new vasoactive peptide, in vascular tissues of low-density lipoprotein receptor deficient (LDLR(-/-)) mice, and to evaluate the effect of salusin-ß on the development of atherosclerosis in LDLR(-/-) mice. Six-week-old, male LDLR(-/-) mice were subcutaneously injected with salusin-ß or the vehicle, once a day for 12 weeks. The expressions of salusin-ß in both mRNA and peptide levels were determined by reverse transcription - polymerase chain reaction, Western blot, and immunohistochemistry. Atherosclerotic lesions were analyzed by staining with hematoxylin and eosin or oil red O. Our results showed that expression of salusin-ß in mRNA and salusin-ß peptide levels were enhanced in LDLR(-/-) mice. Subcutaneous injection of salusin-ß significantly aggravated the atherosclerotic lesions, and increased lipid deposits in the arteries of LDLR(-/-) mice. Moreover, salusin-ß significantly increased the serum level of low-density lipoprotein cholesterol, but not total cholesterol, triglycerides, or high-density lipoprotein cholesterol. These results suggest that the enhanced expression of salusin-ß contributes to progression of atherosclerosis in LDLR(-/-) mice by up-regulating the serum low-density lipoprotein cholesterol level. This study provides a potential therapeutic target for the prevention and treatment of atherosclerosis.


Asunto(s)
Aterosclerosis/metabolismo , Aterosclerosis/patología , Regulación de la Expresión Génica/genética , Péptidos y Proteínas de Señalización Intercelular/biosíntesis , Precursores de Proteínas/biosíntesis , Receptores de LDL/genética , Animales , Arterias/efectos de los fármacos , Arterias/metabolismo , Arterias/patología , Aterosclerosis/sangre , Aterosclerosis/genética , Colesterol/sangre , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Péptidos y Proteínas de Señalización Intercelular/farmacología , Metabolismo de los Lípidos/efectos de los fármacos , Metabolismo de los Lípidos/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Placa Aterosclerótica/inducido químicamente , Placa Aterosclerótica/patología , Precursores de Proteínas/farmacología
5.
Yao Xue Xue Bao ; 45(7): 840-8, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20931780

RESUMEN

The aim of this study is to clarify whether edaravone postconditioning had protective effect against renal ischemia/reperfusion injury and to compare the protective effect between ischemic postconditioning and edaravone postconditioning. Rats were subjected to 45 min ischemia followed by 24 h reperfusion. The rats were randomly assigned to seven groups: a sham-operated control group, an ischemia/reperfusion group, an ischemic postconditioning group, a normal saline vehicle postconditioning group and an edaravone postconditioning (1, 3, and 6 mg x kg(-1)) group. Renal function was assessed by serum creatinine and BUN concentration, while histological damage of renal tissue was assessed with HE staining. MDA content and SOD activity of renal tissue were determined. TUNEL staining was performed to analyze the apoptosis of the tubular epithelial cells, the protein level of Bcl-2 and Bax in renal tissue was examined by Western blotting. Compared to the ischemia/reperfusion group, edaravone postconditioning significantly decreased serum creatinine and BUN concentration, and ameliorated histological damage of renal tissue. MDA was less after 24 h reperfusion in the edaravone postconditioning group than that in the ischemia/reperfusion group, consistent with an increase in SOD activity. In addition, edaravone postconditioning decreased TUNEL-positive cells and Bax expression, and increased Bcl-2 expression. Results detected in the edaravone postconditioning group showed no significant difference from the ischemic postconditioning group. Edaravone administered during the last 3 min of ischemia, prior to reperfusion induces a pharmacological postconditioning in vivo against renal ischemia/reperfusion injury in rats. This protection is similar to that observed with ischemic postconditioning.


Asunto(s)
Antipirina/análogos & derivados , Depuradores de Radicales Libres/uso terapéutico , Poscondicionamiento Isquémico , Riñón/irrigación sanguínea , Daño por Reperfusión/prevención & control , Animales , Antipirina/uso terapéutico , Apoptosis/efectos de los fármacos , Nitrógeno de la Urea Sanguínea , Creatinina/sangre , Edaravona , Riñón/patología , Masculino , Malondialdehído/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Superóxido Dismutasa/metabolismo , Proteína X Asociada a bcl-2/metabolismo
6.
Life Sci ; 80(22): 2067-75, 2007 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-17459422

RESUMEN

Accumulating evidence suggests that c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in renal ischemia/reperfusion injury. However, the downstream mechanism that accounts for the proapoptotic actions of JNK during renal ischemia/reperfusion has not been elucidated. We report that SP600125, a potent, cell-permeable, selective, and reversible inhibitor of c-Jun N-terminal kinase (JNK), potently decreased renal epithelial tubular cell apoptosis induced by renal ischemia/reperfusion via suppression of the extrinsic pathway. This corresponds to the decrease in JNK phosphorylation at 20 min and c-Jun phosphorylation (Ser63/73) at 3 h after renal ischemia. Additionally, SP600125 attenuated the increased expression of FasL induced by ischemia/reperfusion at 3 h. The administration of SP600125 prior to ischemia was also protective. Thus, our findings imply that SP600125 can inhibit the activation of the JNK-c-Jun-FasL pathway and protect renal tubular epithelial cells against ischemia/reperfusion-induced apoptosis. Taken together, these results indicate that targeting the JNK pathway provides a promising therapeutic approach for renal ischemia/reperfusion injury.


Asunto(s)
Antracenos/farmacología , Apoptosis/efectos de los fármacos , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Enfermedades Renales/tratamiento farmacológico , Daño por Reperfusión/tratamiento farmacológico , Animales , Modelos Animales de Enfermedad , Riñón/enzimología , Riñón/patología , Enfermedades Renales/enzimología , Enfermedades Renales/patología , Necrosis/metabolismo , Sustancias Protectoras/farmacología , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/enzimología , Daño por Reperfusión/patología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología
7.
Gene ; 557(2): 146-53, 2015 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-25498336

RESUMEN

Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism and is transported by glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) from the interstitial spaces to the capillary lumen. Here, we cloned a cDNA and the genomic locus of the porcine GPIHBP1 gene, and investigated its tissue expression pattern and its genetic effects on adipose traits. Porcine GPIHBP1 exhibits a four-exon/three-intron structure, including a 543bp open reading frame that encodes 180 amino acids. The porcine GPIHBP1 protein shows 49%-65% homology and shares the major conserved structural domains of GPIHBP1 proteins in other mammals. Porcine GPIHBP1 mRNA levels were high in the adipose tissue, muscle and lung, and higher mRNA levels were observed in sows compared to boars in adipose tissues of the inner and outer layers of subcutaneous fat, abdominal fat, and suet fat. The mRNA expression pattern of porcine GPIHBP1 and LPL genes was similar in most tissues except for the lung. Thirty six single nucleotide polymorphisms (SNPs) were found in the porcine GPIHBP1 gene. Association analyses showed that the g.-255G>C and g.-626T>G SNPs are associated with intramuscular fat content, and that the g.-1557T>C and g.-1948G>A SNPs are associated with back fat thickness. In conclusion, porcine GPIHBP1 mRNA is abundantly expressed in the adipose tissue, muscle and lung, and gender affects GPIHBP1 mRNA expression levels; furthermore, four GPIHBP1 SNPs are genetic factors affecting adipose traits.


Asunto(s)
Receptores de Lipoproteína/genética , Grasa Subcutánea/fisiología , Adiposidad , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Cruzamiento , Clonación Molecular , Femenino , Expresión Génica , Frecuencia de los Genes , Estudios de Asociación Genética , Masculino , Datos de Secuencia Molecular , Especificidad de Órganos , Polimorfismo de Nucleótido Simple , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Lipoproteína/metabolismo , Homología de Secuencia de Ácido Nucleico , Sus scrofa
8.
Yao Xue Xue Bao ; 37(5): 329-33, 2002 May.
Artículo en Zh | MEDLINE | ID: mdl-12579834

RESUMEN

AIM: To investigate the effects of melatonin (MT) on histology and behavioral tests during global cerebral ischemia-reperfusion in gerbils. METHODS: Global cerebral ischemia was induced by occluding the bilateral common carotid arteries for 10 min in gerbils. Three doses of MT were administrated intraperitoneally 30 min prior to the onset of ischemia. Locomotor activity was measured by using the open field method 3 and 7 days after the ischemic episode. T maze test was carried out 4, 5 and 6 days after ischemia to assess the working memory of gerbils. Neuronal damage was assessed in CA1 pyramidal layer of gerbil hippocampus and evaluated 7 days after ischemia. RESULTS: MT significantly reversed the locomotor activity increases, ameliorated learning and working memory deficit, and reduced the extent of CA1 hippocampal pyramidal cells injury after transient global cerebral ischemia in the Mongolian gerbil. CONCLUSION: MT provides significantly protective effect against both histological and behavioral consequences of global cerebral ischemia-reperfusion injury in gerbils.


Asunto(s)
Hipocampo/efectos de los fármacos , Melatonina/uso terapéutico , Fármacos Neuroprotectores/uso terapéutico , Daño por Reperfusión/prevención & control , Animales , Isquemia Encefálica/complicaciones , Femenino , Gerbillinae , Hipocampo/patología , Aprendizaje/efectos de los fármacos , Masculino , Melatonina/farmacología , Memoria/efectos de los fármacos , Actividad Motora/efectos de los fármacos , Neuronas/patología , Fármacos Neuroprotectores/farmacología , Distribución Aleatoria , Daño por Reperfusión/etiología , Daño por Reperfusión/fisiopatología
9.
Gene ; 539(1): 173-9, 2014 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-24487091

RESUMEN

Adipose triglyceride lipase (ATGL), catalyzing the initial step of hydrolysis of triacylglycerol (TAG) in adipocytes, has been known to be inhibited by G0/G1 switch protein 2 (G0S2). In this study, we determined tissue expression pattern and polymorphism of G0S2 gene in porcine. The results showed that the G0S2 transcript levels were very high in the liver and, to a lesser degree, in adipose tissues of greater omentum and suet fat; and low G0S2 transcript levels were observed in other tissues. A comparative study on the transcript levels between ATGL and G0S2 genes showed that ATGL transcript levels were high in all six adipose tissues, but negligible in the liver. Higher transcript levels were obtained for sows in adipose tissues of the inner layer of subcutaneous fat and suet fat, but higher expression values were found for boars in the liver, spleen, and stomach. 19 single nucleotide polymorphisms (SNPs), including 4 nonsynonymous SNPs (g.-307A>T, g.-394C>G, g.-565G>A, and g.-566T>C), were found in porcine G0S2 genomic DNA. Association analyses showed that the g.-565G>A and g.-742T>A SNPs were associated with back fat thickness (BFT). In conclusion, G0S2 mRNAs are abundantly expressed in porcine liver and adipose tissues of greater omentum and suet fat, and sex affects porcine G0S2 tissue transcript levels; meanwhile, the genetic diversity of porcine G0S2 gene is abundant and 2 SNPs are a genetic factor affecting BFT.


Asunto(s)
Adipocitos/enzimología , Tejido Adiposo/enzimología , Proteínas de Ciclo Celular/genética , Lipasa/genética , Hígado/enzimología , Porcinos/genética , Adipocitos/metabolismo , Animales , Secuencia de Bases , Composición Corporal/genética , Femenino , Variación Genética , Masculino , Polimorfismo de Nucleótido Simple , ARN Mensajero/metabolismo , Análisis de Secuencia de ADN , Grasa Subcutánea/metabolismo , Distribución Tisular , Transcripción Genética
10.
Oncol Lett ; 4(6): 1259-1263, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23226801

RESUMEN

Urotensin II (UII), a somatostatin-like cyclic peptide, was originally isolated from the fish urophysis. Our previous study showed that UII stimulates the proliferation of A549 lung adenocarcinoma cells and promotes tumor growth in a nude mouse xenograft model, suggesting that UII may contribute to the pathogenesis of lung adenocarcinoma. In this study, the underlying mechanism for UII to promote lung adenocarcinoma growth was explored by observing the effect of UII on the tumor inflammatory microenvironment in tumor-bearing nude mice. Immunohistochemical analysis showed that UII promoted the infiltration of CD68(+) tumor-associated macrophages (TAMs) in the tumor micro-environment. Enzyme-linked immunosorbent assay (ELISA) demonstrated that UII promoted the release of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-9 (MMP-9). Western blot analysis showed that UII promoted the activation of nuclear factor-κB (NF-κB). These findings suggest that the enhanced levels of IL-6, TNF-α and MMP-9 in the tumor microenvironment, which likely resulted from increased activation of NF-κB induced by UII, may be one of the important mechanisms by which UII promotes lung adenocarcinoma growth. These findings imply that antagonists of UII or urotensin II-receptor (UT-R) have potential for the prevention and treatment of lung adenocarcinoma.

11.
Oncol Rep ; 24(5): 1179-84, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20878108

RESUMEN

Urotensin II (UII), originally identified from fish urophysis, is a potent vasoactive peptide and an endogenous ligand for an orphan G protein-coupled receptor GPR14, now named as urotensin II receptor (UT-R). In this study, we investigated the mRNA and protein expressions of UII and its receptor (UT-R) in human lung adenocarcinoma A549 cells, and the effect of exogenous UII on the proliferation of A549 cells in vitro and in vivo. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis showed that both mRNAs and proteins of UII and UT-R were obviously expressed in human lung adenocarcinoma A549 cells. Immunohistochemical analysis showed that UII peptide was mainly expressed in the cyto-plasm, and UT-R protein was expressed on the cytomembrane and also in the cytoplasm. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) analysis demonstrated that treatment with different concentrations of human UII (10(-9), 10(-8), 10(-7) and 10(-6) M) for 48 h significantly increased the number of A549 cells. The effect of UII at the concentration of 10(-7) M on the proliferation of A549 cells is most pronounced. Nude mice bearing human lung adenocarcinoma A549 cells treated with UII showed a significant increase in tumor volume and tumor weight compared with control group. These findings suggest that UII may contribute to the pathogenesis of human lung adenocarcinoma as an autocrine/paracrine growth stimulating factor.


Asunto(s)
Adenocarcinoma/metabolismo , Neoplasias Pulmonares/metabolismo , Receptores Acoplados a Proteínas G/biosíntesis , Urotensinas/biosíntesis , Urotensinas/farmacología , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/genética , Adenocarcinoma/patología , Animales , Procesos de Crecimiento Celular/efectos de los fármacos , Línea Celular Tumoral , Humanos , Inmunohistoquímica , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores Acoplados a Proteínas G/genética , Urotensinas/genética , Ensayos Antitumor por Modelo de Xenoinjerto
12.
Phytomedicine ; 15(11): 923-31, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18929474

RESUMEN

A new standardized Ginkgo extract (ginaton) destined for i.v. injection was investigated in rats for its protective effect on renal ischemia/reperfusion injury. We report on the elucidation of the downstream mechanism of action of JNK on the renal ischemia/reperfusion injury, which can be explained as the decrease in JNK phosphorylation at 20 min and c-Jun phosphorylation (Ser63/73) at 3h after renal ischemia. At the same time, ginaton attenuated the increased expression of FasL at 3h and caspase3 immunoreactivity at 6h after renal ischemia. Furthermore, ginaton significantly decreased renal epithelial tubular cell apoptosis induced by renal ischemia/reperfusion, alleviating renal ischemia/reperfusion injury. These results cumulatively indicate that ginaton could suppress the JNK-c-Jun-FasL-caspase3 signaling cascade, protecting renal tubular epithelial cells against ischemia/reperfusion-induced apoptosis, which implies that antioxidants may be a potential and effective agent for prevention of the ischemic/reperfusion injury through the suppression extrinsic apoptotic signal pathway induced by JNK signal pathway.


Asunto(s)
Medicamentos Herbarios Chinos/farmacología , Riñón/irrigación sanguínea , Sustancias Protectoras/farmacología , Daño por Reperfusión/prevención & control , Animales , Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Relación Dosis-Respuesta a Droga , Proteína Ligando Fas/metabolismo , Ginkgo biloba , Isquemia/fisiopatología , Isquemia/terapia , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Riñón/patología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Fosforilación/efectos de los fármacos , Ratas , Ratas Sprague-Dawley
13.
Zhonghua Er Ke Za Zhi ; 46(6): 464-7, 2008 Jun.
Artículo en Zh | MEDLINE | ID: mdl-19099789

RESUMEN

OBJECTIVE: To investigate the mechanism of ATP-sensitive potassium channel (K(ATP)) activator cromakalim (CRK) on action potentials and transient inward current (I(ti)) in isolated guinea pig papillary and ventricular myocytes and to explore the mechanisms of effects of I(ti) and K(ATP) treatment in idiopathic ventricular tachycardia. METHODS: The whole-cell patch clamp recording technique was used to detect the action potentials and I(ti) and K(ATP) current alterations during the stimulated and triggered activity. Myocytes were isolated from guinea pig ventricle by enzyme digestion. The experiment was divided into four groups: (1) Control; (2) Control + Ouabain; (3) Control + CRK; (4) Control + Ouabain + CRK. (5) Control + Ouabain + CRK + glibenclamide (GLB). The action potential of guinea pig papillary muscles was measured by using standard microelectrode. The parameters in the experiment included the amplitude (APA), resting potentials (RP), action potentials duration (APD), as well as maximum rise of the action potential (Vmax). RESULTS: (1) When the guinea pig ventricular papillary myocytes were pretreated with Ouabain 0.5 micromol/L, APD prolonged significantly, especially APD(20), APD(50), APD(90). Delayed after depolorazion (DAD) and triggered activity were elicited. I(ti) currents and DAD as well as triggered activity increased. I(ti) current was (126.9 +/- 10.8) pA, lagT (1173.0 +/- 70.9) ms (n = 10, P < 0.01). (2) When guinea pig ventricular myocytes were pretreated with CRK (10 micromol/L), APD was shortened and the amplitude of DAD was lowered. The coupling time in CRK group was significantly prolonged compared with Ouabain group (n = 10, P < 0.01). (3) CRK 50 micromol/L pretreatment of the ventricular myocytes led to an increase of K(ATP) up to (342 +/- 89) pA, which was statistically significant as compared with the control group (P < 0.01). ATP-sensitive potassium channel blocker glibenclamide (10 micromol/L) could antagonize the effects of CRK on APD and I(ti) currents. CONCLUSION: CRK might reduce the toxic effect of Ouabain on cardiomyocytes, shorten APD, terminate DAD and trigger excitation, and have protective effect on cardiomyocytes. The effects of CRK, may be associated with the inhibiting I(ti) current and increasing K(ATP).


Asunto(s)
Cromakalim/farmacología , Miocitos Cardíacos/efectos de los fármacos , Canales de Potasio de Rectificación Interna/agonistas , Potenciales de Acción/efectos de los fármacos , Animales , Cobayas , Ventrículos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/fisiología , Técnicas de Placa-Clamp
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