Intracellular Ca2+ transients in isolated perfused rat heart: measurement using the fluorescent indicator Fura-2AM

Field, Mark L; Azzawi, Ali; Styles, Peter; Henderson, Christopher; Seymour, A.-M.; Radda, George K.

doi:10.1016/0143-4160(94)90004-3

Cited by 21 publications

(13 citation statements)

References 29 publications

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“…The observation is compatible with a previous observation that in conscious pigs, late IP attenuated myocardial stunning and increased expression of HSP70 at the same time (Sun et al, 1995 (Janczewski and Lakatta, 1993), improvement of cardiac contractility is also a result of the restoration of [Ca 2ϩ ] i homeostasis. We found in the present study that resting [Ca 2ϩ ] i rose progressively during 10-min MI/A, an observation reported previously in both whole hearts (Field et al, 1994;Hotta et al, 1998) and isolated myocytes (Seki and MacLeod, 1995) subjected to ischemia, MI/A, or hypoxia. [Ca 2ϩ ] i increased even further into reperfusion, reaching its peak at reperfusion 2 to 3 min, and then declined, but not to the preischemia level.…”

Section: Discussionsupporting

confidence: 70%

Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca²⁺Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults

Liu

Kam²,

Zhou³

et al. 2004

J Pharmacol Exp Ther

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Heat shock protein 70 (HSP70) mediates delayed cardioprotection of preconditioning. Cytosolic calcium ([Ca 2ϩ ] i ) overload precipitates injury, whereas attenuation of [Ca 2ϩ ] i overload is believed to be responsible for cardioprotection. There is evidence suggesting a link between HSP70 and [Ca 2ϩ ] i homeostasis. We hypothesize that activation of HSP70 by preconditioning may restore [Ca 2ϩ ] i homeostasis altered by ischemic insults. To test the hypothesis, we determined the effects of preconditioning with metabolic inhibition or pretreating with U50,488H [trans-(ϩ)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]-benzeneacetamide (a -opioid receptor agonist)] on viability and injury, HSP70 expression, and [Ca 2ϩ ] i in ventricular myocytes subjected to metabolic inhibition and anoxia (MI/A), with blockade of HSP70 synthesis. In myocytes with vehicle pretreatment, the percentage of dead cells determined by trypan blue exclusion, the injury reflected by release of lactate dehydrogenase, and the resting [Ca 2ϩ ] i measured by spectrofluorometry significantly increased, whereas the amplitude of electrically induced [Ca 2ϩ ] i transient decreased, after 10 min with 10 mM 2-deoxy-D-glucose and 10 mM sodium dithionite, known to cause MI/A. However, when myocytes were subjected for 30 min to either 20 mM lactate and 10 mM 2-deoxy-D-glucose (MIP) or 30 M U50,488H (UP) 20 h before MI/A, the changes in viability and injury, and [Ca 2ϩ ] i responses were significantly attenuated. These were accompanied by a significantly increased HSP70 expression. Furthermore, blockade of HSP70 synthesis with selective antisense oligonucleotides abolished the beneficial effects of MIP or UP. This study provides first evidence that activation of HSP70 induced by preconditioning, which conferred delayed cardioprotection, restored partially the [Ca 2ϩ ] i homeostasis altered by ischemic insults.Preconditioning with metabolic inhibition (MIP) or stimulation of -opioid receptor (-OR) with a -OR agonist, U50,488H (UP), has been shown to confer delayed cardioprotection (Wu et al., 1999;Zhou et al., 2001). The protective effect of MIP or UP was accompanied by an enhanced expression of a stress-inducible heat shock protein 70 (HSP70) and blockade of the HSP70 synthesis with a selective antisense (AS) oligonucleotides abolished the protection, indicating that HSP70 mediated the delayed cardioprotection of MIP or UP (Zhou et al., 2001). However, the signaling transduction mechanisms of activation of HSP70 leading to cardioprotection are far from clear.Intracellular Ca 2ϩ ([Ca 2ϩ ] i ) overload is widely believed to be a precipitating cause of myocardial injury upon ischemia and reperfusion (IR) based on the observation that [Ca 2ϩ ] i overload is always associated with myocardial injury upon IR. In support of the notion, a host of experimental studies have shown that calcium channel antagonists limited the infarct size induced by IR (Przyklenk et al., 1999). In a recent study, we found that administration of a c...

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Section: Discussionsupporting

confidence: 70%

Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca²⁺Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults

Liu

Kam²,

Zhou³

et al. 2004

J Pharmacol Exp Ther

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“…The contributions of mitochondria and endothelial cells to total fluorescence have been assessed in several reports (2,(42)(43)(44); the results showed that these components do not affect the kinetic characteristics of Ca 2 transients under an aerobic condition. Field et al estimated that the contributions of mitochondrial and endothelial fura-2 fluorescence to total fluorescence were 43.9 5.5% and 33.6 2.7% in the fura-2 loaded perfused rat heart (42). We confirmed that approximately 50% of fura-2 fluorescence came from the mitochondria in Sprague-Dawley rats (data not shown).…”

Section: Study Limitationsmentioning

confidence: 99%

Impaired Ca2+ Handling in Perfused Hypertrophic Hearts from Dahl Salt-Sensitive Rats

et al. 2003

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“…10 We should consider certain problems arising from using a fluorescent dye to measure [Ca 2+ ]i in the isolated perfused heart. Changes involving a fraction of fura-2 fluorescence derived from nonmyocyte sources, particularly endothelial cells, have been suggested, 14,15,18,39 although the fraction derived from endothelial cells is unlikely to change remarkably during the cardiac cycle. Thus, meaningful differences in [Ca 2+ ]i dynamics could be found between the untreated heart and the KBR-treated heart.…”

Section: Study Limitationsmentioning

confidence: 99%

“…7 A demonstration of an alteration of [Ca 2+ ]i in pathologic models of the whole heart remains elusive; measurements of [Ca 2+ ]i have been carried out mainly in single-cell models and the factors involved in the ischemic whole heart are more complex than in anoxic or hypoxic myocytes. Langendorff's perfused heart loaded with [Ca 2+ ]i indicators has been used, [12][13][14][15][16][17][18] but the influence of NCX inhibition on [Ca 2+ ]i overload induced by ischemia -reperfusion was not addressed in those studies. The present study was designed to test the inhibitory effect of KBR on the increase in [Ca 2+ ]i occurring via the NCX during low-Na + perfusion, and also to determine the effect of KBR on the Ca 2+ transients, including systolic and diastolic fluctuations during low-flow ischemia and reperfusion.…”

mentioning

confidence: 99%

Inhibition by KB-R7943 of the Reverse Mode of the Na+/Ca2+ Exchanger Reduces Ca2+ Overload in Ischemic-Reperfused Rat Hearts.

Seki

Taniguchi

Takeda

et al. 2002

Circ J

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Publication No. 85-23, revised 1996). Adult male Sprague-Dawley rats weighing 300-350 g were anesthetized with pentobarbital Na (30 mg/kg, ip). The heart was quickly isolated and the aorta was cannulated for retrograde Langendorff perfusion. N-2-hydroxy-ethylpiperazine-N'-2-ethanesulfonic acid (HEPES)-buffered Tyrode solution (140 mmol/L NaCl, 6 mmol/L KCl, 1 mmol/L MgCl2, 2 mmol/L CaCl2, 10 mmol/L HEPES, 10 mmol/L J 2002; 66: 390 -396 (Received September 28, 2001; revised manuscript received January 9, 2002; accepted January 11, 2002 ]i dynamics and left ventricular pressure were monitored in perfused beating hearts. The effects of KB-R7943 (KBR), a selective inhibitor of the NCX in the reverse mode, were analyzed during low-Na + exposure and ischemia -reperfusion. Hearts from Sprague-Dawley rats were retrogradely perfused and loaded with 4 mol/L fura-2 to measure the fluorescence ratio as an index of [Ca 2+ ]i. To evaluate KBR effects on the reverse mode exchanger, the increase in [Ca 2+ ]i induced by low-Na + exposure (Na + : 30 mmol/L, 10 mmol/L caffeine pre-treatment) was measured with and without 10 mol/L KBR (n=5). In another series, the hearts were subjected to 10 min of low-flow ischemia with pacing, followed by reperfusion in the absence (n=6) or in the presence of 10 mol/L KBR (n=6). Background autofluorescence was subtracted to estimate the ratio in the ischemia -reperfusion protocol. KBR significantly suppressed the increase in [Ca 2+ ]i induced by low-Na + (40.2±11.2% of control condition, p=0.014), as well as on increase in diastolic [Ca 2+ ]i during ischemia (% increase from pre-ischemia in [Ca 2+ ]i at 10 min: KBR, 17.9±6.4%; no KBR, 44.4±7.7%; p=0.024). After reperfusion, diastolic [Ca 2+ ]i normalized more rapidly in KBR-treated hearts (% increase at 1 min: KBR, 4.5±7.0%; no KBR, 39.8±12.2%; p=0.03). Treatment with KBR also accelerated recovery of the rate -pressure product on reperfusion (1 min: KBR, 8,944±1,554 min -1 ·mmHg; no KBR, 4,970±1,325; p<0.05). Thus, inhibition of the reverse mode exchanger by KBR reduced ischemic Ca 2+ overload and possibly improved functional myocardial recovery during reperfusion in a whole heart model. (Circ J 2002; 66: 390 -396) Circ

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Intracellular Ca2+ transients in isolated perfused rat heart: measurement using the fluorescent indicator Fura-2AM

Cited by 21 publications

References 29 publications

Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca²⁺Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults

Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca²⁺Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults

Impaired Ca2+ Handling in Perfused Hypertrophic Hearts from Dahl Salt-Sensitive Rats

Inhibition by KB-R7943 of the Reverse Mode of the Na+/Ca2+ Exchanger Reduces Ca2+ Overload in Ischemic-Reperfused Rat Hearts.

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Intracellular Ca2+ transients in isolated perfused rat heart: measurement using the fluorescent indicator Fura-2AM

Cited by 21 publications

References 29 publications

Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca2+Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults

Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca2+Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults

Impaired Ca2+ Handling in Perfused Hypertrophic Hearts from Dahl Salt-Sensitive Rats

Inhibition by KB-R7943 of the Reverse Mode of the Na+/Ca2+ Exchanger Reduces Ca2+ Overload in Ischemic-Reperfused Rat Hearts.

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Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca²⁺Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults

Effects of Heat Shock Protein 70 Activation by Metabolic Inhibition Preconditioning or κ-Opioid Receptor Stimulation on Ca²⁺Homeostasis in Rat Ventricular Myocytes Subjected to Ischemic Insults