Effect of Shuangshen Ningxin Capsule in Alleviating Myocardial Ischemia/Reperfusion Injury in Rats by Regulating Mitochondrial ATP-sensitive Potassium Channel / 中国实验方剂学杂志

Objective:To observe the effect of Shuangshen Ningxin capsule in alleviating myocardial ischemia/reperfusion injury in rats by regulating mitochondrial adenosine triphosphate（ATP）-sensitive potassium channels.Method:A total of 56 adult male Sprague-Dawley rats were randomly divided into sham-operated control group (sham), model group (model), Shuangshen Ningxin group (SSNX, 90 mg·kg-1).Shuangshen Ningxin and mitochondrial ATP-sensitive potassium channel (MitoKATP) channel inhibitor group 5-hydroxyl-acid group (SSNX+5-HD, 5 mg·kg-1), with 14 rats in each group. Except the sham operation group, the other three groups received occlusion of left anterior descending coronary artery (LAD) for 45 min, and were sacrificed 3 h after reperfusion. Myocardial ischemia and infarct size were observed by TSC Evans blue staining, and myocardial tissue damage degree was observed by hematoxylin-eosin(HE) staining. The kit was used to measure serum lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase isoenzyme (CK-MB). The ultrastructural changes of mitochondria and mitochondrial autophagy were observed under transmission electron microscope. The changes of mitochondrial membrane potential in cardiomyocytes were detected by fluorescent probe.Result:Compared with the sham group, myocardial infarct size and myocardial ischemic area percentage in the model group were significantly increased, myocardial tissue arrangement was disordered and loose, individual myocardial fibers were broken, cardiomyocytes were necrotic, and serum CK, CK-MB, LDH activities were significantly increased (P<0.01). Mitochondrial membrane potential was significantly decreased (P<0.01), and mitochondrial structure was destroyed by transmission electron microscopy. Compared with the model group, the myocardial tissue of the SSNX group was arranged orderly, and a small amount of cell edema was mildly degenerated. The percentage of myocardial infarct size and myocardial ischemic area was significantly decreased, serum CK, CK-MB, and LDH activities were significantly decreased (P<0.01), while mitochondrial membrane potential increased (P<0.01). Compared with the model group, the SSNX+5-HD group had mild myocardial tissue disorder and mild degeneration of cell edema in some areas, the percentage of myocardial infarct size and myocardial ischemic area was significantly reduced, serum CK, CK-MB, and LDH activities were significantly decreased (P<0.01), and mitochondrial membrane potential increased (P<0.01). Compared with SSNX group, SSNX+5-HD group had significant increase in serum CK, CK-MB and LDH activities (P<0.01), significant increase in the percentage of myocardial infarct size and myocardial ischemic area, and mitochondrial membrane potential Reduced (P<0.05).Conclusion:SSNX protects rat myocardial ischemia-reperfusion injury by opening mitochondrial ATP-sensitive potassium channel.

Antitussive effect and mechanism study of effective fractions from Sauropus rostratus / 中草药

Objective: To study the antitussive effect of Sauropus spatulifolius, screen the active part of its antitussive effect, and study its antitussive mechanism. Methods The acute toxicity of different extraction sites of S. spatulifolius were studied by modified Karber’s method; The model was made with ammonia liquor to induce cough. The spray time that caused half of the mice to cough was calculated by sequential method with aim to screen the active sites. Capsaicin was used to induce cough, and the mechanism of action of extracts from various parts of S. spatulifolius on opioid receptor and ATP-sensitive potassium channel (KATP) of mice was explored. Results The LD50 of 75% ethanol, ethyl acetate, n-butanol, and 95% ethanol extracts was 7.30, 17.00, 69.68, and 75.88 g/kg, respectively; The maximum tolerance dose (MTD) of petroleum ether extracts was 117.71 g/kg; Extracts from 75% ethanol and ethyl acetate had antitussive effects, and its antitussive effect was related to opioid receptor and KATP pathway. Conclusion The fractions from 75% ethanol and ethyl acetate are the active parts of S. spatulifolius for relieving cough, and its antitussive mechanism is related to the KATP pathway and opioid receptors in the excited central system.

Mechanism of " acupuncture for the opening of ATP sensitive potassium channel against cerebral ischemia reperfusion injury in rats / 中国针灸

OBJECTIVE@#To observe the mechanism of "" acupuncture for the opening of ATP sensitive potassium channel (K) against cerebral ischemia reperfusion injury in rats.@*METHODS@#Eighty-four rats were randomly divided into a sham-operation group, a model group, an electroacupuncture (EA) group, an EA+K blocker group, 21 rats in each group. 10 μL intracerebral injection with glipizide (1 μmol/5 μL) was used in the EA+K blocker group. The cerebral ischemia reperfusion model was established by Zea Longa's suture method in the model group, the EA group and the EA+K blocker group. Rats in the sham-operation group were received the same surgery but without nylon filament insertion. Acupuncture (20 min a time) was performed at "Neiguan" (PC 6), "Shuigou" (GV 26) and "Sanyinjiao" (SP 6) in the EA group and the EA+K blocker group at 10:00 and 16:00 for 3 days, firstly 90 min after model establishment. EA (2 Hz/15 Hz, 1 mA) was connected at the affected "Neiguan" (PC 6) and "Sanyinjiao" (SP 6). The same fixation was used in the sham-operation group and the model group, without EA. Neurological function was assessed by Zausinger's neurologic assessment scale. 2, 3, 5-triphenyltetrazolium chloride (TTC) staining was used to detect infarct volume. Neurocyte apoptosis in the hippocampus was detected by flow cytometry and the protein expressions of B lymphocytoma-2 gene (Bcl-2) and B cell lymphoma factor-associated X protein (Bax) were measured by Western-blot.@*RESULTS@#In comparison with the model group, the neurological score of the EA group increased (<0.01); the infarction volume and the hippocampal neuron's total apoptosis rate of the EA group decreased (both <0.05); the protein expression of Bcl-2 and Bcl-2/Bax of the EA group increased (<0.05, <0.01); and the protein expression of Bax of the EA group decreased (<0.01). Compared with the EA group, the neurological score of the EA+K blocker group decreased (<0.05); the total apoptosis rate of hippocampus neurons of the EA+K blocker group increased (<0.05); the expression of Bcl-2 protein of the EA+K blocker group reduced (<0.05); the expression of Bax protein of the EA+K blocker group increased (<0.05).@*CONCLUSION@#"" acupuncture has brain protective effect on rats with focal cerebral ischemia reperfusion injury. The mechanism may be related to regulating the opening of K channels and decreasing the apoptosis of neurons.

Effect of Qibai Pingfei capsule medicated serum on protein expressions of KATP channel in pulmonary arterial smooth muscle cells via nitric oxide / 中国中药杂志

To investigate the ATP-sensitive potassium channel (KATP channel) protein expressions during different periods under hypoxia condition and explore the effect of Qibai Pingfei capsule medicated serum (hereinafter referred to as QBPF) on the correlation between the protein expressions of KATP channel and nitric oxide in rat pulmonary arterial smooth muscle cells(PASMCs). Qibai Pingfei capsules were given to SD rats via continuous gavage for 10 days to obtain QBPF. Primary rats PASMCs were cultured by the direct adherent culture method. Western blot was applied to detect the protein expression levels of KATP channel (Kir6.1 and SUR2B) in PASMCs. Then the noncompetitive inhibitor of NO synthase--Nω-nitro-L-arginine methyl ester(L-NAME) and KATP channel inhibitor--glyburide(GLYB) were applied respectively to evaluate the effect of QBPF on the protein expressions of KATP channel. The protein expressions of Kir6.1 and SUR2B were increased after 6-hour hypoxia treament, peaked at the 24-hour hypoxia treament, and decreased in both 48-hour and 72-hour hypoxia groups. Especially, QBPF could further up-regulate the Kir6.1 and SUR2B protein expressions under 24-hour hypoxia condition; however, such up-regulation effect could be blocked by KATP channel inhibitor GLYB and NO specific inhibitor L-NAME, indicating that QBPF played the role of opening KATP channel. The regulatory mechanism was probably associated with up-regulating KATP channel protein expression via NO relative pathway, involving pulmonary vasodilation, and thus relieving the occurence and development of COPD.

Role of ATP-sensitive potassium channels in inhibitory effect of hydrogen sulfide on high glucose-induced inflammation mediated by necroptosis in H9c2 cardiac cells / 中国病理生理杂志

[ ABSTRACT] AIM:To investigate the role of ATP-sensitive potassium ( KATP ) channels in the inhibitory effect of hydrogen sulfide ( H2 S) on high glucose ( HG)-induced inflammation mediated by necroptosis in H 9c2 cardiac cells. METHODS:The expression levels of receptor-interacting protein 3 ( RIP3; an indicator of necroptosis ) and cyclooxyge-nase-2 (COX-2) were determined by Western blot.The levels of interleukin-1β(IL-1β) and tumor necrosis factor-α( TNF-α) were detected by ELISA .RESULTS:After H9c2 cardiac cells were treated with 35 mmol/L glucose ( HG) for 24 h, the expression of RIP3 was significantly increased .Pre-treatment of the cells with 100 μmol/L diazoxide ( DZ; a KATP channel opener) or 400 μmol/L NaHS (a donor of H2S) for 30 min considerably blocked the up-regulation of RIP3 induced by HG.Moreover, pre-treatment of the cells with 100 μmol/L 5-hydroxydecanoic acid (5-HD; a KATP channel blocker) attenuated the inhibitory effect of NaHS on HG-induced up-regulation of RIP3.On the other hand, co-treatment of the cells with 100μmol/L necrostatin-1 ( a specific inhibitor of necroptosis ) or pre-treatment of the cells with 100 μmol/L DZ or 400 μmol/L NaHS attenuated HG-induced inflammatory responses , evidenced by decreases in the expression of COX-2 and secretion levels of IL-1βand TNF-α.However , pre-treatment of the cells with 100 μmol/L 5-HD significantly attenuated the above anti-inflammatory effects of NaHS.CONCLUSION:KATP channels play an important role in the inhib-itory effect of H2 S on HG-induced inflammation mediated by necroptosis in H 9c2 cardiac cells.

Genetic pathogenesis and current trends in diagnosis and therapy of ATP-sensitive potassium channel congenital hyperinsulinism / 中华实用儿科临床杂志

ATP-sensitive potassium channel congenital hyperinsulinism (KATP-HI) is the most common and most severe type of congenital hyperinsulinism,accounting for 40％-45％.It is due to the inactivating mutations of the ABCC8 and KCNJ11 gene which encode the ATP-sensitive potassium channel.Diazoxide is the main and preferred therapy for KATP-HI.For KATP-HI children who are unresponsive to medical therapy usually need different degrees of pancreatectomy to maintain normal blood sugar level.

Discovery of potential ATP-sensitive potassium channel openers with potential hypotensive activity from Chinese herbs based on molecular simulation / 中国中药杂志

In this research, a combined method of ligand-based pharmacophore (LBP), structure-based pharmacophore (SBP), and molecular docking was applied for virtual screening potential ATP-sensitive potassium channel (KATP) openers from Chinese herbs. LBP models were generated by 3D-QSAR pharmacophore(hypogen) program, based on the training set composed of 48 KATP agonists. The best LBP model consisted of one hydrogen-bond acceptor, one hydrogen-bond donor, one hydrophobic feature, one aromatic ring and five excluded volumes. Besides, the correlation coefficient of training set and test set, N, and CAI value of the model were 0.876 4, 0.705 8, 3.304, and 2.616 respectively. Meanwhile, SBP models were also generated based on a 3D structure of KATP (PMID: PM0079770). The best SBP model consisted of six hydrogen-bond acceptors, eight hydrogen-bond donors, seven hydrophobic features and eighteen excluded volumes. The corresponding N and CAI value were 2.200 and 2.017. Then, the best LBP model and SBP model were applied to identify potential KATP openers from Traditional Chinese Medicine Database(TCMD), respectively. 349 hits were obtained after analyzed by drug-likeness rules. Moreover, 12 compounds with high docking scores were reserved after molecular docking evaluation. Interestingly, part of the results had been verified as hypotensive active ingredients by literatures. Therefore, this study uncovers a specific target effect contained in TCMD, and provides candidates for new KATP openers' research.

Effect and Mechanism of Liraglutide on Vasodilatation of Thoracic Aortic Ring in Experimental Rats / 中国循环杂志

Objective: To investigate the effect and mechanism of liraglutide on vasodilatation of thoracic aortic ring in experimental rats. Methods: The thoracic aortic rings were isolated from 32 male SD rats and divided into 2 groups: Without endothelium group and With intact endothelium group, n=16 in each group. The contractile force of vascular ring was detected and the effect of liraglutide (1×10-5 mol/L) on vasodilatation of norepinephrine (NE, 1×10-6 mol/L) pre-contracted ring was observed. The aortic ring in With intact endothelium group was further divided into 2 sub-groups:①the aortic ring was pre-treated by the inhibitor of nitric oxide synthase (NOS) (L-NAME at 10-4 mol/L),② the aortic ring was pre-treated by non-specific ATP-sensitive-potassium (KATP) channel (Glibenclamide at 10-5 mol/L), n=8 in each group. The impacts of liraglutide on those 2 sub-groups were studied. Results: Liraglutide had no effect on isolated aortic ring at basic condition. Liraglutide at (10-5 mol/L) had vasodilatation effect in both Without endothelium and With intact endothelium groups, the effect was stronger in With intact endothelium group and the maximum vasodilatation reached 17%, P reached 14%, P>0.05. Conclusion: Liraglutide had obvious effect of vasodilatation on NE pre-contracted thoracic aortic ring in experimental rats, the mechanism might be related to NOS, while KATP channel could not block the vasodilatation effect of liraglutide.

Cardioprotective effect of RISK signaling pathway on diazoxide postconditioning in isolated ischemic and reperfused rat hearts / 中国药理学通报

Aim To discuss whether specific mitochon-drial ATP-sensitive potassium channel opener diazoxide ( DZ ) postconditioning activates RISK signaling path-way to protect isolated rat hearts against ischemica reperfusion injury ( IRI ) . Methods Langendorff de-vice was used to establish rat in vitro model of myocar-dial ischemia reperfusion. SD rats were randomly di-vided into normal group ( NOR ) , control group ( CON ) , diazoxide after treatment group ( DZ ) , and LY294002 antagonistic nitrogen Triazine group ( DZ +LY) , with 8 cases in each. The following was com-pared:①whether heart function of each group changed at the end of equilibration and reperfusion; ② at the end of myocardial perfusion and separation, protein was extracted, and protein kinase B ( PKB / Akt ) , P70S6 kinase (P70S6K), endothelial nitric oxide syn-thase ( eNOS) phosphorylation level of expression were analysed by Western blot. Results ① Indicators of changes in heart function: for DZ group at the end of reperfusion , HR , CF , LVDP , LVEDP , +d p/d tmax and -dp/dtmax were significantly better than those in CON group and DZ + LY group ( P 0.05 ) . Conclusion Diazoxide postconditioning through the activation of RISK signa-ling pathway can protect isolated rat hearts against is-chemia reperfusion injury.

Chronic intermittent hypobaric hypoxia enhances vasodilative effects of paeonol on isolated thoracic aorta rings of rats / 中国药理学通报

Aim To investigate the effect of chronic intermittent hypobaric hypoxia ( CIHH) on the paeonol induced vasomotion of isolated rat ’ s thoracic aorta rings and its underlying mechanisms. Methods Spra-gue-Dawlay ( SD ) rats were randomly divided into 2 groups: control group ( CON ) and CIHH treatment group ( CIHH) . CIHH rats were exposed to hypoxia in a hypobaric chamber simulating 5 000 m altitude, 6 hours daily for 28 days. CON rats lived in the same en-vironment as CIHH animals except hypoxia. Organ bath technique was used to observe the effect of pae-onol on isolated thoracic aorta rings of rats. Results There were no significant differences of noradrenaline ( NE )- and KCl-induced contraction in thoracic aorta rings among CIHH and CON rats;CIHH enhanced va-sodilative effects of paeonol on isolated thoracic aorta rings of rats; the vasodilative effects on CIHH rats could be partly decreased by β-receptor blocker prop-ranolol,ATP-sensitive potassium channel ( KATP ) bloc-ker glibenclamide and NO synthase inhibitor L-NAME. Paeonol significantly inhibited NE-induced intracellular and extracellular calcium-dependent contraction in CIHH rats. Paeonol didn ’ t inhibit NE-induced con-traction by intracellular calcium release and its inhibi-tory effect couldn ’ t be blocked by glibenclamide in CON. Vasodilative effects of paeonol couldn ’ t be re-versed by indomethacin, a cyclooxygenase inhibitor, in CIHH and CON rats. Conclusion CIHH significantly enhances vasodilative effects of paeonol on isolated tho-racic aorta rings of rats. Besides promoting the signa-ling pathway of paeonol in CON, CIHH significantly enhances vasodilative effects of paeonol via activating KATP and inhibiting Ca2+ release from sarcoplasmic re-ticulum.

Effects of non-invasive limb ischemic preconditioning on endothelial function after myocardial ischemia-reperfusion injury / 中国药理学通报

Aims To investigate the protective effects of noninvasive limb ischemic preconditioning (LIPC) on myocardial ischemia-reperfusion (I /R)injury,and to explore the mechanism.Methods Healthy male Wistar rats were divided randomly into I /R,I /R +LIPC,I /R +5-Hydroxydecanoate (5-HD)and I /R +LIPC +5-HD groups.The I /R +LIPC and I /R +LIPC-5-HD groups of rats were subjected to three cy-cles of LIPC induction per day with 5 min of reperfu-sion after occlusion for 5 min at the left hind limb for 3 days.All rats were subjected to myocardial I /R injury on the fourth day.The I /R +5-HD and I /R +LIPC-5-HD groups of rats were given the inhibitor of ATP-sen-sitive potassium channel 5-HD before and during myo-cardial I /R injury. Results Compared with I /R group,LIPC reduced myocardial infarct size (P <0.05),lowered cardiocyte apoptosis index and Fas, FasL positive cell number (P <0.01 ),increased the reduced nitric oxide (NO)/endothelin (ET)-1 ratio (P <0.05)in serum in I /R +LIPC group.5-HD a-bolished the protective effects induced by LIPC in I /R+LIPC-5-HD group.Compared with normal myocardi-al tissue,expression of mir-30a-3p was increased in I /R group (P <0.01 )and was decreased in LIPC group (P <0.01 ).Conclusion LIPC alleviates myocardial I /R injury and improves endothelial function. The mechanism may be related with the opening of ATP-sensitive potassium channel,regulating the balance be-tween NO and ET-1 and decreasing the expression of myocardial mir-30a-3p.

Contributions of K ATP within the paraventricular nucleus in the modulation of inflammatory pain in rats / 中国药理学通报

Aim To explore the role of KATP in the pa-raventricular nucleus in inflammatory pain. MethodsMale Sprague-Dawley rats,250~280 g, were randomly assigned into 5 groups ( each, n =6 ): Normal group, Saline group ( for control, subcutaneous injection of 100 μl of saline into the plantar surface of the left hindpaw) , CFA group ( subcutaneous injection of 100μl of complete freund's adjuvant into the plantar sur-face of the left hindpaw) , Vehicle group ( treated with dimethylsulfoxide), KATP selective agonist group(trea-ted with diaoxide) . Rats in each group were tested for TWL with radiant heat apparatus. Immunofluorescent technique was used to label KATP in PVN and c-Fos in lumber spinal cord. Three days after injected with CFA, a selective KATP agonist, diaoxide, was injected into one side of PVN to test its effect on inflammatory pain and c-Fos expression in lumber spinal cord. Re-sults ① Compared with pre-operation and saline group, rats showed significantly lower TWL on day 1, 3, 7 after injection of CFA;the numbers of KATP posi-tive cells were significantly lower; the numbers of c-Fos positive cells were significantly higher. ② Com-pared with those of vehicle group, TWL and the num-ber of c-Fos in lumber spinal cord were both signifi-cantly lower after injection of diaoxide into one side of PVN. Conclusion KATP in PVN is related to inflam-matory pain.

Clinical analysis of 18 cases with congenital hyperinsulinism without response to diazoxide / 中华实用儿科临床杂志

Objective To investigate the clinical features of these children with congenital hyperinsulinism (CHI) who had no response to diazoxide and provide a theoretical foundation for the formulation of CHI treatment strategy.Methods Eighteen patients with CHI who had no response to diazoxide hospitalized in Beijing Children's Hospital from 2008 to 2012 were chosen as research subjects.Their clinical data were analyzed retrospectively.Results There were 18 patients with persistent hypoglycemia after using diazoxide,which indicated that they had no response to diazoxide.Twelve patients of them were born as macrosomia and their onset age was less than 6 months.Half of the children(9/18 cases) even had hypoglycemia in neonatal period.All the manifestations were conformed to the clinical characteristics of ATP-sensitive potassium channel CHI.Four children who were unresponsive to diazoxide received octreotide treatment,and it was effective on them.Four patients had a near-total pancreatectomy.After a long-term followup study,their blood sugar maintained a normal level,and they did not appear serious postoperative complications.Conclusions Children with CHI who have no response to diazoxide are characterized by coming earlier and higher birth weight.Octreotide is proposed in case of non-response to diazoxide.When medical treatment is not efficient in prevention of hypoglycemia,a subtotal pancreatectomy has to be considered as a last resort.

Effects of iptakalim on renal injury induced by lipopolysaccharide, oleic acid and diethylene glycol / 国际药学研究杂志

Objective: To observe the effects of iptakalim on renal injury induced by lipopolysaccharide (LPS), oleic acid and diethylene glycol(DEG). Methods: By njection of 2% ead acetate and 1 μg (1 ml/kg) LPS to rats' femoral vein, 4 h later the experimental models of renal injury induced by LPS have been developed. By injection of 0.15 ml/kg oleic acid to rats' left renal artery, 24h later the experimental models of renal injury induced by oleic acid have been developed. Iptakalim was orally gavaged at the doses of 1,3,9 mg/(kg · d) for 3 d and 1 h before injury. The experimental models of renal injury have been developed by injection of DEG 10 g/kg to mice's peritoneal cavity, then iptakalim was orally gavaged at the doses of 1,3,9 mg/(kg·d) for 6 d. After the experimental models have been set up, observe the serum levels of creatinine(Cr), blood urea nitrogen(BUN) and pathological changes in renal tissue, for the further evaluation of renal function. Results: (1) In rats with the shock induced by LPS, significantly increased serum evels of Cr and BUN were found. Renal cortex of injury rats showed obviously glomerulus microthrombi, tubular cell swelling, necrosis, congestion and cast. Pretreatment of iptakalim at the dose of 9 mg/kg showed improved renal dysfunction and pathological changes in renal tissue. (2) In rats with the renal injury induced by oleic acid, significantly increased serum levels of Cr and BUN were found. Renal cortex of renal injury rats showed obviously glomerulus endothelial cell necrosis, tubular cell congestion and cell cast. Iptakalim had no effect on damaged renal function and the morphological changes in renal tissue. (3) In mice with the renal injury induced by 10 g/kg of DEG, significantly increased serum evels of Cr were found. Iptakalim at the doses of 9 mg/kg decreased serum evels of Cr to normal level. Conclusion: Iptakalim does not fit for individuals of renal damage caused by LPS or oleic acid. The protective effects of iptakalim against renal damaged by DEG need to be further investigated.

Protective effect of hydrogen sulfide on myocardial ischemia reperfusion injury in rats / 中国综合临床

Objective To explore the effects and mechanism of hydrogen sulfide on myocardial ischemia reperfusion in rats. Methods With sodium hydrogen sulfide (NaHS) as a donor of hydrogen sulfide ( H2S), we established myocardial ischemia-reperfusion injury model in rats. The SD rats were randomly divided into control group,myocardial ischemia reperfusion group (I/R group), H2S group,and H2S and glibenclamide (H2S + GLI)group. We monitored the hemodynamics index of rats, including heart rate, arterial pressure, left ventricular pressure. The rate of ventrical arrhythmia was also observed in each group. Results H2 S significantly reduced the ventricular arrhythmia (VA) occurrence (H2S group 66.5% vs I/R group 33.5% (P ＜0.05) and score in myocardial ischemia reperfusion rats (H2S group 2. 6 ±0. 7 vs I/R group 4. 5 ±0. 8(P＜0.05). The KATP channel blocker,glibenclamide,could weaken the antiarrhythmic effects of H2S ( H2S group 2. 6 ±0. 7 vs. H2S + GLI group 4. 0 ± 0. 6, P ＜ 0.05 ). Conclusions H2S has the protective effect against myocardial ischemia reperfusion damage. This function may be associated with the KATP signal transduction pathway in cells.

Effects of Adrenomedullin on Outward Potassium Current in Myocytes from Septic Shock Rats / 华中科技大学学报(医学版)

Objective To study the outward potassium current in myocytes from septic shock rats and the effects of adrenomedullin(ADM).Methods Ventricular myocytes were isolated from adult rats 4 h after an intraperitoneal injection of lipopolysaccharide(LPS,10 mg/kg).Transient outward K~+ current(I_(to)),steady-state K+ current(I_(ss))and ATP sensitive potassium current(I_(K,ATP))were recorded using whole cell patch-clamp methods.Results LPS treatment had no effect on Ito and Iss.The I_(K,ATP) density in septic shock group[(2.66±0.56) pA/pF,n=12]was significantly higher than that in control group[(0.27±0.08) pA/pF,n=14,P＜0.01].The ADM antagonist ADM-(22-52)significantly reversed the increased I_(K,ATP)[(0.69±0.21) pA/pF,n=11,P＜0.01 vs LPS group]in shock myocytes.I_(K,ATP) density was lower in LPS plus aminoguanidine myocytes[(0.77±0.18) pA/pF,n=10,P＜0.01 vs LPS group]than that in LPS myocytes.ADM-(22-52)and 100 μmol/L aminoguanidine could completely abolish the increase in I_(K,ATP).Conclusion I_(K,ATP) was activated in myocytes from septic shock rats.Adrenomedullin along with NO precipitated activation of the I_(K,ATP) in rat ventricular myocytes during septic shock.

The effects of preconditioning with pioglitazone on infarct size and mitochondrial ATP-sensitive potassium channel in rats with ischemia-reperfusion / 中华急诊医学杂志

Objective To observe the effects of preconditioning with pioglitazone on infarct size and mito-chondrial ATP-sensitive potassium channel in rats with ischemia-repedusion, and to explore its possible mecha-nism. Method The whole experiment was divided into experiment Ⅰ and Ⅱ. In experiment Ⅰ, 24 rats were ran-domly divided into four groups (6 rats in each group): (1)Sham-operated (SO) group: the coronary artery of rat was threading without hgation, and the heart was removed by cutting immediately 4 hours later; (2) Isehemia-reperfusion (I/R) group: the rats were administered with 0.9% saline intravenously via caudal vein at 24 hours before iigating the left anterior descending branch of coronary artery for 30 minutes, and followed by reperfusion for 4 hours; (3)5-hydroxydecanoate plus pioglitazone(5HD+Pio) group: the rats were injected with 10 mg/kg 5-hy-droxydecanoate (the blocker of mitochondrial ATP-sensitive potassium channels,) at 24 hours before ligation, and 30 minutes later, 3 mg/kg pioglitazone was given in 5 minutes, and then the rats were subjected to ischemia for 30 minutes, followed by reperfusion for4 hours; (4)pioglitazone treatment group (Pio): the mrs were given 3 mg/kg pioglitazone at 24 hours before occlusion, and then they were treated as done in the 5HD+Pio group. In I/R, 5HD+Pio and Pio group, the hearts were removed by cutting after reperfusion. Western blotting was used to detect the protein expression of P38MAPK, .INK and NFκB P65. In experiment Ⅱ, 30 rats were randomly divided into five groups: SO, I/R, Pio, 5HD+Pio and 5-HD group (rats were treated as done in the rats of I/R group and were injected with 10 mg/kg 5-bydroxydecanoate 24 h before ischemia/reperfusion),and the size of myocardial in-farction and isehemia were measured after reperfusion. Statistical analyses were performed using SPSS10.0 soft-ware. Multiple comparisons were analyzed by one-way analysis of variance (SNK-q test). P<0.05 was consid-ered statistically significant. Results (1) The infarct size in i/R group was(34.93±5.55)%, while pioglita-zone reduced the infarct size to(20.24±3.93)% (P<0.05). There was no significant difference between I/R and 5-HD±Pio or 5-HD groups (P>0.05). Compared with the sham-operated group, the expression of P38MAPKmRNA, JNKmRNA and protein of P38MAPK, JNK and NFκB P65 in I/R increased (P<0.05). Com-pared with the I/R group, pioglitazone inhibited these undue expressions (P<0.05). Conclusions Pioglitazone could protect the heart from ischemia-reperfusion injury evidenced by reducing infarct size. These protective effects of pioglitazone may be related to opening mitochondrial ATP-seusitive potassium channels or downregulation of JNK and p38 MAPK signaling, leading to the overexpression of NFκB p65 activation.

The Mechanism of R-PIA Induced Mechanical Antiallodynia in a Peripheral Neuropathic Rat / 대한마취과학회지

BACKGROUND: The injury by a nerve ligation produces a mechanical allodynia. The antiallodynic effect resulted from intrathecal administration of the adenosine analogues has been well known. ATP-sensitive potassium channel blockers have been known to reverse the effect of some antinociceptive drugs in animal and human studies. Therefore, the present study is to assess the relationship between antiallodynic effect of N6-(R)-phenylisopropyl adenosine (R-PIA) and mitochondrial ATP-sensitive potassium (mKATP) channel in a neuropathic pain model. METHODS: Allodynia was induced in male Sprague Dawley rats by the tight ligation of the left lumbar 5th and 6th spinal nerves. We tested the mechanical allodynia by pricking von Frey filaments to the left hind paw and assessed withdrawal thresholds of paw with up-down method. For the estimation of the antiallodynic effect of R-PIA, R-PIA (0.5, 1 and 2microgram) or saline were administered intrathecally.To investigate the reversal effect on antiallodynic effect of R-PIA, variable amounts of 5-hydroxydecanoate (5-HD, 20, 30 and 40 mg), mKATP channel blocker were administered intraperitoneally at 5 min prior to the intrathecal injection of 2microgram of R-PIA, and the degree of allodynia was assessed. RESULTS: The paw withdrawal threshold was gradually increased with increased dose of R-PIA and reached the maximum level with 2microgram R-PIA (P < 0.05). The increase of paw withdrawal threshold with 2microgram R-PIA was significantly reversed dose-dependently by intraperitoneal pretreatment of 20, 30 and 40 mg/kg 5-HD (P < 0.05). CONCLUSIONS: In our results, intraperitoneal injection of 5-HD before intrathecal injection of R-PIA had reversed the antiallodynic effect of R-PIA. This results suggest that the mechanism of mechanical antiallodynia induced by intrathecal injection of R-PIA may relate with the mK(ATP) channel in a rat model of nerve ligation injury.

Effect of K_(ATP) Channel Regulators on the Expression of K_(ATP) Subunits on the Cerebral Ischemia Reperfusion Injury in Gerbil / 航天医学与医学工程

Objective To investigate the effect of KATP channel regulator on the expression of KATP subunits on the cerebral ischemia reperfusion injury(I-R) in gerbil.Methods The I-R models of gerbil were performed by occlusion common carotid artery for 10 min and reperfusion for 60 min.Forty eight gerbils were randomly divided into 8 groups: sham-operated group,I-R group,I-R+diazoxide pretreatment group,I-R+5-Hydroxydecanoate(5-HD) pretreatment group,I-R+diazoxide+5-HD pretreatment group,I-R+ pinacidil pretreatment group,I-R+glibenclamide pretreatment group,I-R+pinacidil+glibenclamide pretreatment group.Pre I-R,the gerbil of each group was injected with KATP openers or blockers correspondingly,and the expressions of Kir6.1,SUR1,SUR2 mRNA in brain tissue were detected by reverse transcriptase-polymerase chain reaction(RT-PCR).Results Compared with sham-operated group,the expression of Kir6.1 mRNA in I-R group was increased significantly.Compared with I-R group,the expression of Kir6.1 mRNA in diazoxide pretreatment group was increased significantly,whereas that in glibenclamide treatment group was decreased significantly.Compared with sham-operated group,the expression of SUR2 mRNA was increased significantly both in I-R groups and pharmacologic pretreatment groups.However,there was no difference among KATP opener and blocker groups.And the expression of SUR1 mRNA was no difference in sham-operated group,I-R group and pharmacologic pretreatment groups.Conclusion Kir6.1 mRNA is increased significantly with diazoxide pretreatment.Kir6.1 subunit plays an important role in protection of cerebral ischemia reperfusion injury.However,SUR1 mRNA and SUR2 mRNA are not influenced by the KATP regulators.

The Effect of ATP-sensitive Potassium Channel on R-PIA Induced Mechanical Antiallodynia in a Peripheral Neuropathic Rat / 대한통증학회지

BACKGROUND: Nerve ligation injury may produce mechanical allodynia, but this can be reversed after an intrathecal administration of adenosine analogues. In many animal and human studies, ATP-sensitive potassium channel blockers have been known to reverse the antinociceptive effect of various drugs. This study was performed to evaluate the mechanical antiallodynic effects of spinal R-PIA (Adenosine A1 receptor agonist) and the reversal of these effects due to pretreatment with glibenclamide (ATP-sensitive potassium channel blocker). Thus, the relationship between the antiallodynic effects of R-PIA and ATP-sensitive potassium channel were investigated in a neuropathic model. METHODS: Male Sprague Dawley rats were prepared by tightly ligating the left lumbar 5th and 6th spinal nerves and implantation of a chronic lumbar intrathecal catheter for drug administration. The mechanical allodynia was measured by applying von Frey filaments ipsilateral to the lesioned hind paw. And the thresholds for paw withdrawal assessed. In study 1, either R-PIA (0.5, 1 and 2microgram) or saline were administered intrathecally for the examination of the antiallodynic effect of R-PIA. In study 2, glibenclamide (2, 5, 10 and 20 nM) was administered intrathecally 5 min prior to an R-PIA injection for investigation of the reversal of the antiallodynic effects of R-PIA. RESULTS: The antiallodynic effect of R-PIA was produced in a dose dependent manner. In study 1, the paw withdrawal threshold was significantly increased with 2microgram R-PIA (P < 0.05). In study 2, the paw withdrawal threshold with 2microgram R-PIA was significantly decreased almost dose dependently by intrathecal pretreatment of 5, 10 and 20 nM glibenclamide (P < 0.05). CONCLUSIONS: These results demonstrated that an intrathecal injection of ATP-sensitive potassium channel blockers prior to an intrathecal injection of adenosine A1 receptors agonist had an antagonistic effect on R-PIA induced antiallodynia. The results suggest that the mechanism of mechanical antiallodynia, as induced by an intrathecal injection of R-PIA, may involve the ATP-sensitive potassium channel at both the spinal and supraspinal level in a rat nerve ligation injury model.