scholarly journals Characterization of Two Novel Pharmacological ATP-Sensitive Potassium Channels Modulators in Isolated Rat Heart Mitochondria

2014 ◽  
Author(s):  
Alexandra Petrus ◽  
Oana Duicu ◽  
Adrian Sturza ◽  
Lavinia Noveanu ◽  
István Baczkó ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Rat Heart ◽  
Ischemia Reperfusion ◽  
Isolated Rat Heart ◽  
Heart Mitochondria ◽  
Retention Capacity ◽  
Calcium Retention ◽  
Rat Heart Mitochondria ◽  
Calcium Retention Capacity ◽  
Isolated Rat

Background Mitochondrial dysfunction plays a major role in the pathogenesis of ischemia/reperfusion injury and cardiac arrhythmias. Mitochondrial ATP-sensitive potassium channel (mitoKATP) openers such as diazoxide and pinacidil have been reported to elicit cardioprotective effects via mild uncoupling and/or respiratory chain inhibition. The aim of the present study was to characterize the effects of two novel mitoKATP modulators (KL-1488 and KL 1495) on the respiratory rates and calcium retention capacity of isolated rat heart mitochondria. Methods Mitochondrial respiratory function was assessed by high-resolution respirometry (Oxygraph-2k Oroboros Ltd.) at 370C according to the Substrate-Uncoupler-Inhibitor Titration (SUIT) protocol, as follows: complex I (CI) and complex II (CII) dependent respiration was stimulated by glutamate + malate and rotenone + succinate, respectively (State 2) and subsequent ADP (State 3, OXPHOS state) addition; cytochrome c addition evaluated the intactness of the outer mitochondrial membrane; ATP synthase was inhibited by oligomycin (State 4); uncoupled respiration was obtained by FCCP titration; respiration was inhibited with antimycin A. Calcium retention capacity (CRC) was determined by spectrofluorimetry and calculated as the amount of calcium taken by mitochondria before opening of the mitochondrial permeability transition pore (mPTP) in the presence of the pharmacological agents. Results For both C I and C II-supported respiration, 150 µM of KL 1495 (but not of KL 1488) significantly increased respiratory rates in State 2 and 4, and decreased State 3 respiration, respectively. No inhibition of mPTP opening was observed in the presence of either compound. Conclusion The mitochondrial uncoupling and respiratory chain inhibition induced by KL 1495 could play a role in cardioprotection during the postischemic reperfusion. The research was funded by the POSDRU grant no. 159/1.5/S/136893 titled “Parteneriat strategic pentru creșterea calității cercetării științifice din universitățile medicale prin acordarea de burse doctorale și postdoctorale – DocMed.Net_2.0” (A.P.).

scholarly journals Effect of Chronic Continuous Normobaric Hypoxia on Functional State of Cardiac Mitochondria and Tolerance of Isolated Rat Heart to Ischemia and Reperfusion: Role of µ and δ2 Opioid Receptors

2019 ◽  
pp. 909-920 ◽  
Author(s):  
E.S. Prokudina ◽  
N.V. Naryzhnaya ◽  
A.V. Mukhomedzyanov ◽  
A.S. Gorbunov ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Opioid Receptors ◽  
Mitochondrial Function ◽  
Rat Heart ◽  
Contractile Function ◽  
Isolated Rat Heart ◽  
Retention Capacity ◽  
Calcium Retention ◽  
Calcium Retention Capacity ◽  
Isolated Rat

Chronic continuous normobaric hypoxia (CNH) increases cardiac tolerance to ischemia/reperfusion injury in vivo and this effect is mediated via µ and δ2 opioid receptors (ORs) activation. CNH has also been shown to be cardioprotective in isolated rat heart. In this study, we hypothesize that this cardioprotective effect of CNH is mediated by activation of µ and δ2 ORs and preservation of mitochondrial function. Hearts from rats adapted to CNH (12 % oxygen) for 3 weeks were extracted, perfused in the Langendorff mode and subjected to 45 min of global ischemia and 30 min of reperfusion. Intervention groups were pretreated for 10 min with antagonists for different OR types: naloxone (300 nmol/l), the selective δ OR antagonist TIPP(ψ) (30 nmol/l), the selective δ1 OR antagonist BNTX (1 nmol/l), the selective δ2 OR antagonist naltriben (1 nmol/l), the selective peptide μ OR antagonist CTAP (100 nmol/l) and the selective κ OR antagonist nor-binaltorphimine (3 nmol/l). Creatine kinase activity in coronary effluent and cardiac contractile function were monitored to assess cardiac injury and functional impairment. Additionally, cardiac tissue was collected to measure ATP and to isolate mitochondria to measure respiration rate and calcium retention capacity. Adaptation to CNH decreased myocardial creatine kinase release during reperfusion and improved the postischemic recovery of contractile function. Additionally, CNH improved mitochondrial state 3 and uncoupled respiration rates, ADP/O, mitochondrial transmembrane potential and calcium retention capacity and myocardial ATP level during reperfusion compared to the normoxic group. These protective effects were completely abolished by naloxone, TIPP(ψ), naltriben, CTAP but not BNTX or nor-binaltorphimine. These results suggest that cardioprotection associated with adaptation to CNH is mediated by µ and δ2 opioid receptors activation and preservation of mitochondrial function.

Effects of pinacidil and calcium on isolated rat heart mitochondria

2012 ◽  
Vol 443 (1) ◽  
pp. 113-117 ◽  
Author(s):  
S. M. Korotkov ◽  
L. V. Emel’yanova ◽  
I. V. Brailovskaya ◽  
V. P. Nesterov
Keyword(s):  
Rat Heart ◽  
Isolated Rat Heart ◽  
Heart Mitochondria ◽  
Rat Heart Mitochondria ◽  
Isolated Rat

Uncoupling and Antioxidant Effects of Ursolic Acid in Isolated Rat Heart Mitochondria

2011 ◽  
Vol 74 (7) ◽  
pp. 1640-1644 ◽  
Author(s):  
Julius Liobikas ◽  
Daiva Majiene ◽  
Sonata Trumbeckaite ◽  
Lolita Kursvietiene ◽  
Ruta Masteikova ◽  
...  
Keyword(s):  
Ursolic Acid ◽  
Rat Heart ◽  
Isolated Rat Heart ◽  
Heart Mitochondria ◽  
Rat Heart Mitochondria ◽  
Antioxidant Effects ◽  
Isolated Rat

scholarly journals Celecoxib Decreases Mitochondrial Complex IV Activity and Induces Oxidative Stress in Isolated Rat Heart Mitochondria: An Analysis for its Cardiotoxic Adverse Effect

2020 ◽  
Author(s):  
Saman Atashbar ◽  
Elham Mohammad Khanlou ◽  
Saleh Khezri ◽  
Peyman Kurdpour ◽  
Ahmad Salimi
Keyword(s):  
Lipid Peroxidation ◽  
Rat Heart ◽  
Isolated Rat Heart ◽  
Mitochondrial Swelling ◽  
Heart Mitochondria ◽  
Isolated Mitochondria ◽  
Biochemical Assays ◽  
Ros Formation ◽  
Rat Heart Mitochondria ◽  
Isolated Rat

Abstract Background In spite of the cardiotoxic effect of selective cyclooxygenase-2 inhibitors, they are most widely used as anti-inflammatory and analgesic drugs. Today, valdecoxib and rofecoxib have been withdrawn on the market but celecoxib remains. In this study, we focused on an analysis of celecoxib toxic effects on isolated mitochondrial. Methods isolated rat heart mitochondria were obtained using differential centrifugation. Using flowcytometry and biochemical assays we searched succinate dehydrogenases (SDH), mitochondrial membrane potential (MMP), reactive oxygen species (ROS) formation, mitochondrial swelling, lipid peroxidation and mitochondrial complexes activity in rat heart isolated mitochondria. Results In here our results indicated a significant decrease in activity of complexes IV after exposure with celecoxib (16 µg/ml). This decrease in activity of complexes IV is paralleled by the MMP collapse, ROS formation, mitochondrial swelling and lipid peroxidation. Conclusion For the first time, this introductory study has showed a significant decrease in activity of complexes IV and mitochondrial dysfunction after exposure with celecoxib in rat heart isolated mitochondria.

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