Role of succinate dehydrogenase in hypoxic postconditioning-induced reduction of hypoxia-reoxygenation injury in myocardial cells of rats and the relationship with mito-K ATP / 中华麻醉学杂志

Objective:To evaluate the role of succinate dehydrogenase (SDH) in hypoxic postconditioning (HPC)-induced reduction of hypoxia-reoxygenation (H/R) injury in myocardial cells of rats and the relationship with mitochondrial ATP-sensitive potassium channels (mito-K ATP). Methods:Myocardial cells isolated from adult male Sprague-Dawley rats were cultured for 48 h and then divided into 7 groups ( n=24 each) using a random number table method: blank control group (Nor group), H/R group, SDHA-siRNA adenovirus+ H/R group (siRNA+ H/R group), HPC group, SDHA-siRNA adenovirus+ HPC group (siRNA+ HPC group), 5-HD+ HPC group, and SDHA-siRNA adenovirus+ 5-HD+ HPC group (siRNA+ 5-HD+ HPC group). Nor group was continuously cultured for 195 min under normoxic conditions. The H/R injury model was prepared by exposing the cells to hypoxia for 45 min in 5% CO 2 + 1% O 2 + 94% N 2, followed by reoxygenation for 150 min. The HPC method involved three cycles of 5 min reoxygenation/5 min hypoxia at the end of 45 min ischemia before 120 min reoxygenation. The mito-K ATP blocker 5-HD administration method involved adding 5-HD at a final concentration of 100 μmol/L at 30 min of hypoxia. The myocardial cells in each siRNA group were successfully transfected with SDHA-siRNA adenovirus to silence SDHA expression. The cell viability, calcium ion level, SDH activity, ATP content, degree of mitochondrial permeability transition pore (mPTP) opening, and mitochondrial membrane potential (MMP) were measured at the end of reoxygenation. Results:Compared with Nor group, the cell viability, ATP content and MMP were significantly decreased, and the degree of mPTP opening, level of calcium ion and activity of SDH were increased in H/R group ( P<0.05). Compared with H/R group, the cell viability, ATP content and MMP were significantly increased, and the degree of mPTP opening, calcium ion level and SDH activity were decreased in siRNA+ H/R group and HPC group ( P<0.05). Compared with HPC group, the cell viability, ATP content and MMP were significantly decreased, and the degree of mPTP opening, calcium ion level and SDH activity were increased in 5-HD+ HPC group ( P<0.05), and the cell viability, ATP content and MMP were significantly increased, and the degree of mPTP opening, calcium ion level and SDH activity were decreased in siRNA+ HPC group ( P<0.05). Compared with siRNA+ HPC group, the cell viability, ATP content and MMP were significantly decreased, the opening degree of mPTP and calcium ion level were increased ( P<0.05), and no significant change was found in the SDH activity in siRNA+ 5-HD+ HPC group ( P>0.05). Compared with 5-HD+ HPC group, the SDH activity was significantly decreased, and no significant change was found in the other parameters in siRNA+ 5-HD+ HPC group ( P>0.05). Conclusions:HPC alleviates H/R injury probably by reducing SDH activity and opening mito-K ATP in myocardial cells of rats.

Thoracic aortic reactivity in obese patients submitted to aerobic exercise / Reatividade da aorta torácica em pacientes obesos submetidos ao exercício aeróbico / Reactividad de la aorta torácica en pacientes obesos sometidos a ejercicio aeróbico

ABSTRACT Introduction: Aerobic exercise can improve the function of the cardiovascular circulatory system, reducing morbidity and mortality from cardiovascular disease by stimulating the production of endogenous self-protection. Activating potassium channels in vascular smooth muscle cells can cause vasodilation and increase blood flow, lowering blood pressure. There is a sensitivity to intracellular ATP and ADP concentration among the variety of potassium channels distributed in vascular smooth muscle cells, which vary mainly during aerobic physical activity. Objective: Explore the effect of aerobic exercise on the vascular reactivity of the thoracic aorta in patients with obesity and hyperlipidemia. Methods: Randomized controlled trial in twenty male Wistar rats weighing 250g and two months old. The control group remained at rest while the experimental group performed aerobic exercise on a treadmill at increasing speed for eight weeks. The rats were dissected, and dilatators and vasoconstrictors drugs stimulated their blood vessels in a tamponade solution. Observation of vascular changes was measured under controlled tensioning. Results: The blockade of KATP channels in vascular smooth muscle caused tonic contraction of vascular smooth muscle cells and increased blood pressure. Conclusion: Long-term regular aerobic exercise may induce changes in rats' thoracic aortic vascular function and vascular smooth muscle reactivity. Aerobic exercise can also significantly improve the activity of KATP channels. Evidence Level II; Therapeutic Studies - Investigating the results.

RESUMO Introdução: O exercício aeróbico pode melhorar a função do sistema circulatório cardiovascular, reduzindo a morbidade e mortalidade de doenças cardiovasculares estimulando a produção de autoproteções endógenas. A ativação de canais de potássio nas células musculares lisas vasculares pode causar vasodilatação e aumentar o fluxo sanguíneo, diminuindo a pressão sanguínea. Há uma sensível a concentração de ATP intracelular e ADP dentre a variedade de canais de potássio distribuídos em células musculares lisas vasculares, que variam principalmente durante a atividade física aeróbica. Objetivo: Explorar o efeito do exercício aeróbico na reatividade vascular da aorta torácica em pacientes com obesidade e hiperlipidemia. Métodos: Estudo randomizado controlado em vinte ratos Wistar machos de 250g e 2 meses de idade. O grupo controle permaneceu sob repouso enquanto o experimental realizava exercícios aeróbicos em esteira com velocidade crescente durante 8 semanas. Os ratos foram dissecados e seus vasos sanguíneos estimulados com drogas vasoconstritoras e dilatadoras em solução tampão. A observação das alterações vasculares foi mensurada sob tensionamento controlado. Resultados: O bloqueio dos canais KATP no músculo liso vascular causou contração tônica das células musculares lisas vasculares e aumento da pressão arterial. Conclusão: Exercícios aeróbicos regulares de longo prazo podem induzir alterações na função vascular da aorta torácica e reatividade do músculo liso vascular em ratos. O exercício aeróbico também pode melhorar significativamente a atividade dos canais KATP. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: El ejercicio aeróbico puede mejorar la función del sistema circulatorio cardiovascular, reduciendo la morbilidad y la mortalidad de las enfermedades cardiovasculares al estimular la producción de autoprotección endógena. La activación de los canales de potasio en las células del músculo liso vascular puede causar vasodilatación y aumentar el flujo sanguíneo, reduciendo la presión arterial. Existe una sensibilidad a la concentración intracelular de ATP y ADP entre la variedad de canales de potasio distribuidos en las células del músculo liso vascular, que varían principalmente durante la actividad física aeróbica. Objetivo: Explorar el efecto del ejercicio aeróbico sobre la reactividad vascular de la aorta torácica en pacientes con obesidad e hiperlipidemia. Métodos: Ensayo controlado aleatorio en veinte ratas Wistar macho de 250 g y 2 meses de edad. El grupo de control permaneció en reposo mientras que el grupo experimental realizó ejercicios aeróbicos en una cinta de correr a velocidad creciente durante 8 semanas. Las ratas fueron disecadas y sus vasos sanguíneos fueron estimulados con fármacos vasoconstrictores y dilatadores en solución amortiguada. La observación de los cambios vasculares se midió bajo tensión controlada. Resultados: El bloqueo de los canales KATP en el músculo liso vascular provocó una contracción tónica de las células del músculo liso vascular y un aumento de la presión arterial. Conclusión: El ejercicio aeróbico regular a largo plazo puede inducir cambios en la función vascular de la aorta torácica y en la reactividad del músculo liso vascular en ratas. El ejercicio aeróbico también puede mejorar significativamente la actividad del canal KATP. Nivel de evidencia II; Estudios terapéuticos - Investigación de resultados.

Role of caveolin-eNOS platform and mitochondrial ATP-sensitive potassium channel in abrogated cardioprotective effect of ischemic preconditioning in postmenopausal women

Abstract Caveolin, the protein of the caveolar membrane, interacts and binds with endothelial nitric oxide synthase (eNOS), forming a caveolin-eNOS complex leading to suppression of the eNOS activity. Caveolin, therefore, maintains eNOS in the inactivated state leading to reduced nitric oxide (NO) production. Ischemic preconditioning disrupts the caveolin-eNOS complex leading to activation of the eNOS and thus results in cardioprotection. During ischemic preconditioning, NO produces cardioprotection by the opening of the KATP channel, and the caveolin forms a suitable signalling platform facilitating the interaction of NO with the KATP channel. Estrogen deficiency has been reported to upregulate caveolin-1 expression. The article aims to review the various mechanisms that placed the women at the risk of coronary artery diseases after postmenopausal estrogen deficiency and their role in the cardioprotective effect of ischemic preconditioning.

Dinámica estructural entre la conformación abierta y cerrada del canal KATP en células pancreáticas / Structural dynamics between the open and closed conformations of the KATP channel in pancreatic cells

INTRODUCCIÓN: el canal de Potasio sensible a ATP (canal KATP) regula la producción de Insulina por células ß pancreáticas. La Glibenclamida (GBM) (fármaco antidiabético) y el ATP actúan como inhibidores de este canal, mientras que el ADP lo activa. El canal KATP es un octámero constituido por 4 subunidades centrales Kir6.2 que forman el poro y 4 subunidades externas de regulación SUR1. OBJETIVO: determinar la dinámica estructural entre las conformaciones abierta y cerrada del canal KATP en células pancreáticas. MÉTODO: análisis estructural comparativo de diferentes estructuras cristalográficas del canal KATP de células pancreáticas humanas empleando el software Chimera v1.11.2 RESULTADOS: La subunidad Kir6.2 presenta un dominio de unión a PIP2 (activador), una Hélice Interfacial (IFH) y un dominio N-terminal (KNtp). Por otro lado, la subunidad SUR1 que contiene el sitio de unión a la GBM, tiene 2 Dominios de Unión a Nucleótidos (NBD1/2), un bucle M5-Lh1 y un Motivo de Lazo formado por la interface entre el Dominio Trans-membrana 0 y el Bucle 0 (TMD0-L0). Los resultados del análisis dinámico estructural mediante herramientas bioinformáticas, indican que estas regiones participan activamente en los cambios conformacionales que dan lugar al cierre (inhibición) o apertura (activación) de este canal. CONCLUSIÓN: El estudio de la dinámica de activación e inhibición de los canales KATP es imprescindible para la evaluación, descubrimiento y/o diseño de nuevos compuestos naturales, que como la GBM, puedan promover la secreción de Insulina para coadyuvar o mejorar el tratamiento de pacientes diabéticos.

INTRODUCTION: the ATP-sensitive Potassium channel (KATP channel) regulates insulin production by pancreatic ß cells. Glibenclamide (GBM) (antidiabetic drug) and ATP act as inhibitors of this channel, while ADP activates it. The KATP channel is an octamer consisting of 4 central Kir6.2 subunits that form the pore and 4 external regulation subunits SUR1. OBJECTIVE: to determine the structural dynamics between the open and closed conformations of the KATP channel in pancreatic cells. METHOD: comparative structural analysis of different crystallographic structures of the KATP channel of human pancreatic cells using Chimera v1.11.2. RESULTS: the Kir6.2 subunit has a PIP2 binding domain (activator), an Interfacial Helix (IFH) and an N-terminal domain (KNtp). On the other hand, the SUR1 subunit that contains the GBM binding site, has 2 Nucleotide Binding Domains (NBD1/2), an M5-Lh1 loop and a Lasso Motif formed by the interface between the Trans-membrane Domain 0 and Loop 0 (TMD0-L0). The results of the dynamic structural analysis using bioinformatics tools indicate that these regions participate actively in the conformational changes that lead to the closure (inhibition) or opening (activation) of this channel. CONCLUSION: the study of the dynamics of activation and inhibition of the KATP channels is essential for the evaluation, discovery and/or design of new natural compounds, which like GBM, can promote insulin secretion to aid or improve the treatment of diabetic patients.

Effect of chronic intermittent hypobaric hypoxia on relaxation of aorta and mechanisms in developing rats / 中国药理学通报

Aim To investigate the effect of chronic intermittent hypobaric hypoxia (CIHH) on relaxation of thoracic aorta rings in male developing rats and the underlying mechanisms. Methods Male neonatal Spra-gue-Dawlay ( SD) rats were randomly divided into eight groups respectively: CIHH treatment group (CIHH), group of one-week post-CIHH (CIHH-pl), group of two-week post-CIHH ( CIHH-p2 ) , group of three-week post-CIHH (CIHH-p3 ) , control group for CIHH (Con), control group for CIHH-pl (Con-1), control group for CIHH-p2 ( Con-2) and control group for CIHH-p3 (Con-3 ). Rats in CIHH groups were put into a hypobaric chamber with the mother rats 1 ~ 3 days before the birth to get a hypobaric hypoxia exposure mimicking 3 km altitude for 42 days, 5 hours daily. Rats in control groups were kept in the same environment as CIHH rats except hypoxia exposure. After anaesthetized with pentobarbital sodium (50 mg • kg-1 i. p. ), the thorax of rats was opened and thoracic aorta rings were made. The artery rings were placed in the bath chamber filled with K-H solution, and the relaxation of artery rings was recorded under normoxia or a-cute hypoxia conditions, respectively. Results (1) Under normoxia condition, the acetylcholine ( ACh)-induced relaxation of thoracic aorta increased obviously in CIHH groups compared with corresponding Con groups ( P < 0. 05 ). ( 2 ) The enhancing effect of CIHH treatment on thoracic aorta could be maintained for at least three weeks (P < 0. 05). (3 ) Under acute hypoxia condition, ACh-induced relaxation of thoracic aorta in each group decreased obviously, but the decrease in CIHH groups was significant less than that in Con groups ( P < 0.05 ). (4) The enhancement of CIHH on relaxation of thoracic aorta could be reversed by indomethacin (Indo), a cyclooxygenase inhibitor, glibenclamide (Gli), a KATP blocker, and Tempo, a free radical scavenger. Conclusions CIHH augments endothelium-dependent relaxation in thoracic aorta of developing rats. Also, CIHH can antagonize the inhibition of acute hypoxia on relaxation of thoracic aorta. The enhancing effect of CIHH treatment may be related with the increase of prostacyclin, the opening of KATP and free radical production.

Effect of compatibility of Aconitum carmichaelii and Cornus officinalis on chronic heart failure rats / 中草药

Objective To study the efficacy enhancing and toxicity reducing effects of compatibility of Aconitum carmichaeli and Cornus officinalis on chronic heart failure (CHF) rats. Methods The CHF rats was established by ip injection of adriamycin (ADM), the CHF rats were administrated tested drugs for three weeks by means of ig administration, the tested drugs included extracts of A. carmichaeli, C. officinalis, and Compound. The serum brain natriuretic peptide (BNP) level, activity of Ca2+-ATP and Na+, K+-ATP enzymes in cardiac myocytes, and cardiac histopathology were measured. Results After three weeks of modeling, the CHF rats showed signs of ascites, loss of weight, loose stool, hogback, etc. The left ventricular ejection fraction (EF) and fraction shortening (FS) decreased significantly, and the level of BNP in serum was significantly improved; Pathological changes of ventricular tissue included rupture of myocardial fibers, degeneration and necrosis of cardiomyocytes, etc. After three weeks of gavage compatibility of A. carmichaeli and C. officinalis, the general state and cardiac histopathology of the animal was obviously improved, the level of BNP in serum was reduced significantly, the activity of Na+, K+-ATP enzymes was increased significantly. No notable improvement in the above indexes was obtained after administration of A. carmichaeli and C. officinalis alone. Conclusion The compatibility of A. carmichaeli and C. officinalis can increase the activity of Na+, K+-ATP enzyme in cardiac myocytes, and improve the energy metabolism and activity of cardiac myocytes in chronic heart failure. The compatibility of A. carmichaeli and C. officinalis play the key role of enhancing efficacy and reducing toxicity.

Role of sarcolemmal KATP channel in sevoflurane-induced maintenance of electrophysiological stabili-ty of ventricular myocardium in diabetic rats / 中华麻醉学杂志

Objective To evaluate the role of sarcolemmal ATP-sensitive potassium ( sarcKATP ) channel in sevoflurane-induced maintenance of electrophysiological stability of ventricular myocardium in di-abetic rats. Methods Clean-grade healthy male Sprague-Dawley rats, aged 3 months, weighing 280-320 g, in which diabetes mellitus ( DM) was induced by intraperitoneal streptozotocin 60 mg/kg and confirmed by blood glucose ≥16. 7 mmol/L, were used in this study. Their hearts were excised after anesthesia and retrogradely perfused in a Langendorff apparatus at 4 weeks after establishing the DM model. Twenty-four Langendorff-perfused hearts were divided into 3 groups ( n=8 each) using a random number table method:DM group ( group D) , DM plus sevoflurane group ( group DS) and DM plus sevoflurane plus HMR-1098 group (group DSH). Another 8 Langendorff-perfused hearts of normal rats were selected as control group ( group C) . Hearts were perfused with 37℃ K-H solution via the aorta in each group, 15 min of equilibra-tion later hearts were continuously perfused for 30 min with K-H solution in C and D groups, with K-H solu-tion saturated with 2. 5％ sevoflurane in group DS, or with K-H solution saturated with 10 μmol/L HMR-1098 and 2. 5％ sevoflurane in group DSH. Monophasic action potential (MAP) duration at 50％ and 90％repolarization ( MAPD50 and MAPD90 ) in the endocardium and epicardium of the left ventricular anterior wall were recorded at 15 min of equilibration ( T0 ) and 15 and 30 min of reperfusion ( T1,2 ) , transmural dispersion of repolarization ( TDR) was calculated. S1S2 program-controlled stimulation was performed at the end of perfusion to record the effective refractory period (ERP), ventricular arrhythmia (VA) induced and the longest pacing cycle length ( PCL) of ventricular fibrillation threshold ( VFT) induced. ERP/MAPD90 ratio was calculated. Results Compared with group C, TDR was significantly increased at T0 , ERP/MADP90 ratio was decreased, the incidence of VA induced was increased, and the longest PCL of VFT induced was prolonged in group D ( P＜0. 05) . Compared with group D, TDR was significantly decreased at T2 in group DS (P＜0. 05), and ERP/MADP90 ratio was significantly increased, the incidence of VA in-duced was decreased, and the longest PCL of VFT induced was shortened in DS and DSH groups ( P＜0. 05). TDR was significantly smaller at T2 in group DSH than in group DS (P＜0. 05). Conclusion sarcKATP channel is involved in sevoflurane-induced maintenance of electrophysiological stability of ventricu-lar myocardium in diabetic rats.

Role of mitochondrial ATP-sensitive potassium channels inurocot postconditioning-induced protection of rat cardiomyocytes / 中华麻醉学杂志

Objective To evaluate the role of mitochondrial ATP-sensitive potassium (mito-KATP) channels in urocortin postconditioning-induced protection of rat cardiomyocytes.Methods Clean-grade healthy male Sprague-Dawley rats,aged 16-20 weeks,weighing 200-250 g,were used in this study.Cardiomyocytes of rats were isolated,cuhured and divided into 4 groups (n =28 each) using a random number table method:control group (group C),H/R group (group HR),urocortin postconditioning group (group U) and 5-hydroxydecanoate (5-HD,mito-KAw channel blocker) plus urocortin postconditioning group (group HU).In group C,the cells were continuously cultured for 150 min in an incubator filled with 95％ O2-5％ CO2 at 37 ℃.In group HR,the cells were exposed to 40-min hypoxia in an incubator filled with 95％ N2-5％ CO2 at 37 ℃,followed by 110-min reoxygenation.In group U,the cells were exposed to 40-min of hypoxia,followed by 10-min reoxygenation,and then cultured in a cuhure medium containing 10-8mmol/L urocortin for 30 min,followed by 70-min reoxygenation.In group HU,the cells were cultured for 10 min in a culture medium containing 10-4mmol/L 5-HD,and the other treatments were similar to those previously described in group U.At the end of reoxygenation,the opening of mitochondrial permeability transition pore (mPTP) and mitochondrial membrane potential (MMP) were measured by fluorescence spectrophotometry.The expression of Bax and Bcl-2 was determined by Western blot,and the cell viability was measured by CCK-8 assay.Results Compared with group C,the viability of cardiomyocytes and MMP were significantly decreased,the opening of mPTP was increased,the expression of Bcl-2 was down-regulated,and the expression of Bax was up-regulated in the other 3 groups (P＜0.05).Compared with group HR,the viability of cardiomyocytes and MMP were significantly increased,the opening of mPTP was decreased,the expression of Bcl-2 was up-regulated,and the expression of Bax was down-regulated in group U,and the opening of mPTP was decreased (P ＜ 0.05),and no significant change was found in the other parameters in group HU (P＞0.05).Compared with group U,the viability of cardiomyocytes and MMP were significantly decreased,the opening of mPTP was increased,the expression of Bcl-2 was down-regulated,and the expression of Bax was up-regulated in group HU (P＜0.05).Conclusion The mechanism by which urocortin postconditioning attenuates H/R-induced damage to rat cardiomyocytes is associated with promoting mito-KATP channel opening and inhibiting mPTP opening.

Effects of corticotropin-releasing hormone on the expression of adenosine triphosphate-sensitive potassium channels (Kir6.1/SUR2B) in human term pregnant myometrium

OBJECTIVE: Corticotropin-releasing hormone (CRH) is a crucial regulator of human pregnancy and parturition. Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels are important for regulating myometrial quiescence during pregnancy. We investigated regulatory effects of different concentrations of CRH on KATP channel expression in human myometrial smooth muscle cells (HSMCs) in in vitro conditions. METHODS: After treating HSMCs with different concentrations of CRH (1, 10, 102, 103, 104 pmol/L), mRNA and protein expression of KATP channel subunits (Kir6.1 and SUR2B) was analyzed by reverse transcription-polymerase chain reaction and western blot. We investigated which CRH receptor was involved in the reaction and measured the effects of CRH on intracellular Ca2+ concentration when oxytocin was administered in HSMCs using Fluo-8 AM ester. RESULTS: When HSMCs were treated with low (1 pmol/L) and high (103, 104 pmol/L) CRH concentrations, KATP channel expression significantly increased and decreased, respectively. SUR2B mRNA expression at low and high CRH concentrations was significantly antagonized by antalarmin (CRH receptor-1 antagonist) and astressin 2b (CRH receptor-2 antagonist), respectively; however, Kir6.1 mRNA expression was not affected. After oxytocin treatment, the intracellular Ca2+ concentration in CRH-treated HSMCs was significantly lowered in low concentration of CRH (1 pmol/L), but not in high concentration of CRH (103 pmol/L), compared to control. CONCLUSION: Our data demonstrated the regulatory effect was different when HSMCs were treated with low (early pregnancy-like) and high (labor-like) CRH concentrations and the KATP channel expression showed significant increase and decrease. This could cause inhibition and activation, respectively, of uterine muscle contraction, demonstrating opposite dual actions of CRH.

Ligand binding and conformational changes of SUR1 subunit in pancreatic ATP-sensitive potassium channels

ATP-sensitive potassium channels (K) are energy sensors on the plasma membrane. By sensing the intracellular ADP/ATP ratio of β-cells, pancreatic K channels control insulin release and regulate metabolism at the whole body level. They are implicated in many metabolic disorders and diseases and are therefore important drug targets. Here, we present three structures of pancreatic K channels solved by cryo-electron microscopy (cryo-EM), at resolutions ranging from 4.1 to 4.5 Å. These structures depict the binding site of the antidiabetic drug glibenclamide, indicate how Kir6.2 (inward-rectifying potassium channel 6.2) N-terminus participates in the coupling between the peripheral SUR1 (sulfonylurea receptor 1) subunit and the central Kir6.2 channel, reveal the binding mode of activating nucleotides, and suggest the mechanism of how Mg-ADP binding on nucleotide binding domains (NBDs) drives a conformational change of the SUR1 subunit.

Mechanisms involved in adenosine pharmacological preconditioning-induced cardioprotection

Adenosine is a naturally occurring breakdown product of adenosine triphosphate and plays an important role in different physiological and pathological conditions. Adenosine also serves as an important trigger in ischemic and remote preconditioning and its release may impart cardioprotection. Exogenous administration of adenosine in the form of adenosine preconditioning may also protect heart from ischemia-reperfusion injury. Endogenous release of adenosine during ischemic/remote preconditioning or exogenous adenosine during pharmacological preconditioning activates adenosine receptors to activate plethora of mechanisms, which either independently or in association with one another may confer cardioprotection during ischemia-reperfusion injury. These mechanisms include activation of K(ATP) channels, an increase in the levels of antioxidant enzymes, functional interaction with opioid receptors; increase in nitric oxide production; decrease in inflammation; activation of transient receptor potential vanilloid (TRPV) channels; activation of kinases such as protein kinase B (Akt), protein kinase C, tyrosine kinase, mitogen activated protein (MAP) kinases such as ERK 1/2, p38 MAP kinases and MAP kinase kinase (MEK 1) MMP. The present review discusses the role and mechanisms involved in adenosine preconditioning-induced cardioprotection.

The research progress of mitoKATP in diabetes with cerebral ischemic injury / 天津医药

@#Diabetes is an important independent risk factor for cerebrovascular diseases. A large number of clinical and experimental studies have confirmed that diabetes can aggravate cerebral ischemic injury, but the mechanism is not yet clear. Mitochondrial ATP-sensitive potassium channel (mitoKATP) is an important ion channel located in the mitochondrial inner membrane, playing very important roles in many physiological and pathological processes. In recent years, studies have showed that mitoKATP has a protective effect on cerebral ischemic neuronal injury, but its protective mechanism is abolished in diabetes. The relationship between mitoKATP and diabetes with cerebral ischemic injury has attracted more and more attention. In this article, the role of brain mitoKATP in diabetes with cerebral ischemic injury was reviewed.

Role of mito-KATP channel in pinacidil postconditioning-induced reduction of myocardial ischemia-reperfusion injury in rats: an in vitro experiment / 中华麻醉学杂志

Objective To evaluate the role of mitochondrial KATP (mito-KATP) channel in pinacidil postconditioning-induced reduction of myocardial ischemia-reperfusion (I/R) injury in rats.Methods SPF healthy male Sprague-Dawley rats,aged 16-20 weeks,weighing 250-300 g,were anesthetized with pentobarbital.Their hearts were excised and perfused in a Langendorff apparatus with K-H solution saturated with 95％ O2-5％ CO2 at 36.5-37.5 ℃.Thirty-two Langendorff-perfused hearts were divided into 4 groups (n =8 each) using a random number table:control group (group C),group I/R,pinacidil postconditioning group (group P) and 5-hydroxy decanoic acid plus pinacidil postconditioning group (group 5-HD+P).Myocardial ischemia was induced by interrupting perfusion for 40 min followed by 60 min reperfusion.Immediately after onset of reperfusion,hearts were perfused with K-H solution containing 50 μmol/L pinacidil for 2 min and then with K-H solution for 58 min in group P,hearts were perfused with K-H solution containing 100 μmol/L 5-HD for 5 min,with K-H solution containing 50 μmol/L pinacidil for 2 min and then with K-H solution for 53 min in group 5-HD+P.The heart rate (HR),left ventricular developed pressure (LVDP),left ventricular end-diastolic pressure (LVEDP) and the maximum rate of increase in left ventricular pressure (+dp/dtmax) were recorded at 20 min of equilibration (T1) and at the end of reperfusion (T2).Myocardial tissues were obtained at T2 for determination of myocardial infarct size and for examination of myocardial ultrastructure and Flameng scoring of the mitochondria was performed.Results Compared with group C,the HR,LVDP and +dp/dtmax were significantly decreased,and the LVEDP,myocardial infarct size and mitochondrial Flameng score were increased at T2 in group I/R (P＜0.05).Compared with group I/R,the HR,LVDP and +dp/dtmax were significantly increased and the LVEDP,myocardial infarct size and mitochondrial Flameng score were decreased at T2 (P＜0.05),and the pathological changes of myocardium were significantly attenuated in group P,and no significant change was found in the parameters mentioned above in group 5-HD+P (P＞0.05).Compared with group P,the HR,LVDP and + dp/dtmax were significantly decreased and the LVEDP,myocardial infarct size and mitochondrial Flameng score were increased at T2 (P＜O.05),and the pathological changes of myocardium were accentuated in group 5-HD+P.Conclusion The whole mechanism by which pinacidil postconditioning reduces myocardial I/R injury is related to promoting opening of mito-KATP channel in rats.

Role of mitochondrial ATP-sensitive potassium channel in reduction of myocardial ischemia-reperfusion injury by calcitonin gene-related peptide in rats : an in vitro experiment / 中华麻醉学杂志

Objective To evaluate the role of the mitochondrial ATP-sensitive potassium (mitoKATP) channel in reduction of myocardial ischemia-reperfusion (I/R) injury by calcitonin gene-related peptide (CGRP) in rats in an in vitro experiment.Methods Healthy adult male Sprague-Dawley rats,weighing 250-300 g,were used in this study.After the animals were anesthetized,their hearts were immediately removed and retrogradely perfused with oxygenated K-H solution at 37 ℃ in a Langendorff apparatus.Twenty-four isolated rat hearts were assigned into 4 groups (n =6 each) using a random number table:control group (C group),I/R group,CGRP group and 5-hydroxydecanoate (5-HD) group.The hearts were first perfused with K-H solution for 30 min in the three groups.The hearts were continuously perfused with K-H solution for 150 min in group C.The hearts were subjected to ischemia for 30 min followed by 120 min of reperfusion to establish the model of myocardial I/R injury.In group CGRP,after the hearts were perfused with K-H solution for 10 min,10-8 mol/L CGRP was infused for 20 min at a rate of 0.5 ml/min via the aorta,and then the model of myocardial I/R injury was established.In 5-HD group,specific mito-KATP channel blocker 5-HD 100 μmol/L was infused for 10 min at a rate of 0.5 ml/nin via the aorta,and the other treatments were similar to those previously described in CGRP group.At the end of equilibration and 30,60,90 and 120 min of reperfusion,heart rate (HR),left ventricular systolic pressure (LVSP),left ventricular end-diastolic pressure (LVEDP) and the maximum rate of increase or decrease in left ventricular pressure (±dp/dtmax) were recorded.The myocardial infarct size was measured by 2,3,5-triphenyltetrazolium chloride staining at 120 min of reperfusion.Results Compared with C group,HR,LVSP and ±dp/dtmax were significantly decreased and LVEDP was increased during reperfusion,and the percentage of myocardial infarct size was increased at 120 min of reperfusion in the other three groups (P＜0.05).Compared with I/R group,HR,LVSP and ±dp/dtmax were significantly increased and LVEDP was decreased during reperfusion,and the percentage of nyocardial infarct size was decreased at 120 min of reperfusion in CGRP group (P＜0.05).Compared with CGRP group,HR,LVSP and ±dp/dtmax were significantly decreased and LVEDP was increased during reperfusion,and the percentage of myocardial infarct size was increased at 120 min of reperfusion in 5-HD group (P＜0.05).Conclusion Opening of mito-KATP channels is involved in CGRP-iuduced reduction of myocardial I/R injury in rats in an in vitro experiment.

Role of mitochondrial ATP-sensitive potassium channels in dexmedetomidine-induced attenuation of myocardial ischemia-reperfusion injury in rats / 中华麻醉学杂志

Objective To evaluate the role of mitochondrial ATP-sensitive potassium(mito-KATP) channels in dexmedetomidine-induced attenuation of myocardial ischemia-reperfusion(I∕R)injury in rats. Methods Forty pathogen-free healthy male Sprague-Dawley rats, aged 8-12 weeks, weighing 200-350 g, were divided into 5 groups(n=8 each)using a random number table: sham operation group(group S), I∕R group, dexmedetomidine group(group DEX), a specific mito-KATPchannel blocker 5-hydroxyde-canoate(5-HD)group(group 5-HD)and dexmedetomidine plus 5-HD group(group DEX+5-HD). Myo-cardial I∕R was produced by occlusion of the anterior descending branch of the left coronary artery for 30 min followed by 120 min reperfusion in pentobarbital sodium-anesthetized rats. Dexmedetomidine 5 μg∕kg was intraperitoneally injected at 15 min prior to reperfusion in group DEX.5-HD 40 mg∕kg was intraperitoneally injected at 30 min prior to reperfusion in group 5-HD. In group DEX+5-HD, 5-HD 40 mg∕kg and dexme-detomidine 5 μg∕kg were intraperitoneally injected at 30 and 15 min prior to reperfusion, respectively. The parameters of cardiac function such as left ventricular systolic pressure(LVSP), left ventricular end-dias-tolic pressure(LVEDP)and the maximum rate of increase or decrease in left ventricular pressure(±dp∕dtmax)were recorded before ischemia(T0)and at 60 and 120 min of reperfusion(T1,2). Blood samples were collected from the carotid artery at the end of reperfusion for determination of the concentrations of cre-atine kinase-MB(CK-MB)and cardiac troponin I(cTnI)in serum. The animals were then sacrificed, and hearts were removed for determination of the myocardial infarct size in the left ventricular myocardial tissues. Results Compared with group S, the LVSP and ±dp∕dtmaxwere significantly decreased, and the LVEDP was increased at T1-2, and the concentrations of CK-MB and cTnI in serum and myocardial infarct size were increased in the other groups(P<0.05). Compared with group I∕R, the LVSP and ±dp∕dtmaxwere signifi-cantly increased, and the LVEDP was decreased at T1-2, and the concentrations of CK-MB and cTnI in ser-um and myocardial infarct size were decreased in group DEX, and the LVSP and ±dp∕dtmaxwere significant-ly increased at T1-2, the concentrations of CK-MB and cTnI in serum and myocardial infarct size were de-creased(P<0.05), and no significant change was found in LVEDP in group DEX+5-HD, and no signifi-cont change was found in the parameters mentioned above in group 5-HD(P>0.05). Compared with group DEX, the LVSP and ±dp∕dtmaxwere significantly decreased, and the LVEDP was increased at T1-2, and the concentrations of CK-MB and cTnI in serum and myocardial infarct size were increased in DEX+5-HD group(P<0.05). Conclusion The mechanism by which dexmedetomidine attenuates myocardial I∕R inju-ry is partially related to promotion of mito-KATPchannel opening in rats.

MiR-20 Regulates Myocardiac Ischemia by Targeting KATP Subunit Kir6.1 / 华中科技大学学报（医学）（英德文版）

This study aimed to examine the functional role of microRNA-20 (miR-20) and its potential target,Kir6.1,in ischemic myocardiocytes.The expression of miR-20 was detected by real-time PCR.Myocardiocytes were stained with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) reagent for apoptosis evaluation.Western blotting was used to detect the Kit6.1 protein in ischemic myocardiocytes transfected with miR-20 mimics or inhibitors.Luciferase reporter gene assay was performed to confirm the targeting effect of miR-20 on KCNJ8.The results showed that miR-20 was remarkably down-regulated,while the KATP subunit Kir6.1 was significantly up-regulated,during myocardial ischemia.The miR-20 overexpression promoted the apoptosis of ischemic myocardiocytes,but showed no such effect on normal cells.Under ischemic condition,myocardiocytes transfected with miR-20 mimics expressed less Kir6.1.On the contrary,inhibiting miR-20 increased the expression of Kir6.1 in the cells.Co-transfection of miR-20 mimics with the KCNJ8 3’-UTR plasmid into HEK293 cells consistently produced less luciferase activity than transfection of the plasmid alone.It was concluded that miR-20 may regulate myocardiac ischemia by targeting KATP subunit Kir6.1 to accelerate the cell apoptosis.Therefore miR-20 may serve as a therapeutic target for myocardial ischemic disease.

Efeito protetor do Nitrosil-Rutênio (Cis[Ru(bpy)2SO3NO]+(PF6) em modelos experimentaisde lesões gástricas em camundongos – envolvimento da via NO/GCS/KATP

Lesões gástricas relacionadas ao consumo excessivo de antiinflamatórios não esteroidais (AINEs) e etanol possuem um importante papel na gastroenterologia clínica. Fármacos com ação anti-secretória gástrica, como os inibidores da bomba de prótons, representam a principal opção na terapia destas patologias. Objetivo: Avaliar o efeito do doador de NO nitrosil-rutênio (Rut-NO) na defesa da mucosa gástrica em modelos experimentais de lesão gástrica em camundongos e a participação da guanilato ciclase solúvel (GCs) e dos canais de KATP neste efeito. Métodos: Protocolo1-Camundongos swiss foram pré-tratados com Rut-NO (3mg/Kg, v.o), rutênio (2.3mg/Kg, v.o) ou nitroprussiato (NPS) na dose de 10mg/kg, v.o, meia hora antes da administração por gavagem de etanol 50%. Em outro grupo, os animais foram pré-tratados com ODQ (10mg/Kg, v.o) ou glibenclamida (10mg/Kg,i.p) trinta minutos ou 1h antes, respectivamente dos tratamentos citados anteriormente.Depois de 1h, os animais foram sacrificados e os estômagos removidos para a avaliação das lesões gástricas por planimetria computadorizada. Além disso, fragmentos de tecido foram removidos para análise microscópica e dosagem de glutationa (GSH) e malondialdeído (MDA)...

Gastric lesions associated to excessive consumption of nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol have an important role in clinical gastroenterology. The drugs with gastric antisecretory action, suchas proton pump inhibitors, represent the main option in the treatment of these pathologies. Aim: To evaluate the effect of NO donor nitrosyl-ruthenium (Rut-NO) in gastric mucosal defense in experimental models of gastric damage in mice, as wellthe involvement of soluble guanylate cyclase (sGC) and KATPchannels in this effect. Methods: Protocol 1-mice were pre-treated with Rut-NO (3mg/Kg, vo), ruthenium (2.3mg/Kg, p.o) or nitroprusside (SNP) at a dose of 10mg/kg, p.o, half an hour before administration by gavage of 50% ethanol. In another group, the animals were pre-treated with ODQ (10mg/kg, po) or glibenclamide (10mg/kg, ip) thirty minutes or 1 hour prior, respectively,the treatments mentioned above. After 1h, the animals were sacrificed and the stomachsremoved for evaluation of gastric lesions by computerized planimetry. In addition, fragments of tissue were removed for microscopic analysis and measurement of glutathione (GSH) and malondialdehyde (MDA) levels...

Scanning and analysis of the KATP channel mutations in 12 cases of infancy onset type 1 diabetes mellitus / 中华实用儿科临床杂志

Objective To screen the mutation of KATP channel mutations in Chinese pedigrees with infantile onset type 1 diabetes mellitus (T1DM) and neonatal diabetes mellitus.Methods A cohort of 12 children of infant onset T1DM and neonatal diabetes mellitus admitted into Beijing Children's Hospital between March 2004 and June 2013 were selected.PCR amplification and direct sequencing were used to analyze the 39 exons of ABCC8 gene and one exon of KCNJ11.And the mutational sites of the parents of the probands was sequenced in order to identify the inheritance.Results Analysis revealed ABCC8 mutation in 25％ (3/12 cases) of the patients,a case of transient neonatal diabetes (TNDM),a case of permanent neonatal diabetes mellitus (PNDM) and a case of infant onset T1DM.All positive patients showed a known heterozygosis mutation in the ABCC8 gene(R1182Q,c.3545G ＞ A,D209E,c.627C ＞ G,E208K c.622G ＞ A).The residue R1182Q,which was located at a position involved in joining transmembrane domain 2 to nucleotide binding domain 2,the mutations E208K and D209E were located in the intracellular region that links the transmembrane domain with the gatekeeper module.All the three mutations were located throughout the cytoplasm part of SUR1 protein.The TNDM successfully transferred from insulin to oral sulfonylureas therapy.Conclusions There is a complex genetic pathogenesis in neonatal and infant-onset diabetes.The KATP channel activating mutations is one of the main causes of neonatal diabetes mellitus and may cause T1DM in infants in China.Oral Glibenclamide therapy seems highly effective for some patients with the KATP channel activating mutations.

A case report on congenital hyperinsulinism associated with ABCC8 nonsense mutation: Good response to octreotide / Journal of the ASEAN Federation of Endocrine Societies

@#<p style="text-align: justify;">A 2.4 kg baby boy born via Caesarian section at 35 weeks had the first onset of hypoglycemia at 2 hours of life. The infant required a glucose load of 30 mg/kg/min. Insulin level was 19.6 pmol/L (normal value 17.8-173.0) in the absence of ketosis. He was resistant to oral diazoxide but responded to octreotide infusion. The boy was found to be heterozygous for an ABCC8 nonsense mutation, p.R934*. We present our experience on the use of subcutaneous octreotide for 2 years for the treatment of diazoxide resistant congenital hyperinsulinism (CHI).</p>

Effect of sevoflurane postconditioning on mitochondrial connexin 43 during myocardial ischemia-reperfusion in rats and the role of mito-KATP channels: an in vitro experiment / 中华麻醉学杂志

Objective To investigate the effect of sevoflurane postconditioning on mitochondrial connexin 43 (Cx43) during myocardial ischemia-reperfusion (I/R) in isolated rat hearts and the role of mitochondrial ATP-sensitive potassium (mito-KATP) channels in it.Methods Forty-five adult male SpragueDawley rats,weighing 200-250 g,were used in the study.Their hearts were excised and retrogradely perfused with K-H solution in a Langendorff apparatus.The 45 isolated hearts were assigned into 5 groups (n =9 each) using a random number table:control group (group C),I/R group,sevoflurane postconditioning group (group Sev),and sevoflurane postconditioning plus 5-hydroxydecanoate (5-HD,a specific mitoKATp channel blocker) group (group Sev+5-HD) and I/R plus 5-HD group (group I/R+5-HD).The hearts were subjected to 20 main of global ischemia followed by 90 min of reperfusion to establish the model of myocardial I/R injury.From the beginning of reperfusion,the hearts were perfused with K-H solution saturated with 3％ sevoflurane for 15 min in group Sev,with K-H solution saturated with 3％ sevoflurane and containing 100 μ mol/L 5-HD in group Sev+5-HD,and with K-H solution containing 100 μ mol/L 5-HD in group 5-HD.The heart rate (HR),left ventricular end-diastolic pressure (LVEDP),left ventricular developed pressure (LVDP) and the maximum rate of increase and decrease of ventricular pressure (±dp/dtmax) were recorded at the end of equilibration (T1) and 30 and 60 min of reperfusion (T2,3).At 90 min of reperfusion,the myocardial infarct size was measured by TTC staining,and the expression of total Cx43 (tCx43)and phosphorylated Cx43 (p-Cx43) in mitochondria was determined by Western blot analysis.The percentage of myocardial infarct size and p-Cx43/tCx43 ratio were calculated.Results Compared with group C,the HR,LVDP and ±dp/dtmax were significantly decreased,and the LVEDP was increased at T2,3,and the percentage of myocardial infarct size was increased in the other 4 groups,the expression of mitochondrial tCx43 and p-Cx43 was significantly down-regulated in I/R,Sev+5-HD and 5-HD groups (P＜0.05),and no significant change was found in the expression of mitochondrial tCx43 and p-Cx43 in group Sev (P＞0.05).Compared with group I/R,the HR,LVDP and ±dp/dtmax were significantly increased,and the LVEDP was decreased at T2,3,the percentage of myocardial infarct size was decreased,and the expression of mitochondrial tCx43 and p-Cx43 was up-regulated in group Sev (P＜0.05),and no significant change was found in the parameters mentioned above in Sev+5-HD and 5-HD groups (P＞0.05).Compared with group Sev,the HR,LVDP and ±dp/dt were significantly decreased,and the LVEDP was increased at T2,3,the percentage of myocardial infarct size was increased,and the expression of mitochondrial tCx43 and p-Cx43 was down-regulated in group Sev+5-HD (P＜0.05).There was no significant change in the pCx43/tCx43 ratio between the five groups (P＞0.05).Conclusion The mechanism by which sevoflurane postconditioning attenuates myocardial I/R injury may be related to induction of mito-KATP channel opening and up-regulation of the expression of mitochondrial Cx43 in cardiomyocytes of rats.