Effect of chloride on Ca 2+ release from the sarcoplasmic reticulum of mechanically skinned skeletal muscle fibres

Coonan, Jason R.; Lamb, Graham D.

doi:10.1007/s004240050574

Cited by 18 publications

(16 citation statements)

References 35 publications

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“…The area under the curve (integral) of the force response after treatment with L-lactate was then compared with the average integral of control responses before and after treatment. The integral of the caffeine response has been previously shown to be approximately linearly proportional to the length of time the fiber is loaded (5,8,28). Thus the integral of the force response provides a good indication of the amount of releasable Ca 2ϩ in the SR.…”

Section: Methodsmentioning

confidence: 98%

“…Determination of net Ca 2ϩ leak from the SR. The methods employed in this study have been previously described in detail (5,8,28). Briefly, the SR of a skinned fiber was first depleted of virtually all the total SR Ca 2ϩ content with a K-HDTA solution containing 0.05 mM free [Mg 2ϩ ], 30 mM caffeine, and 0.5 mM total EGTA (termed the caffeine solution).…”

Section: Methodsmentioning

confidence: 99%

“…Effect of L-lactate on net Ca 2ϩ leak from the SR. The effects of L-lactate on the response to depolarization may be due in part to a reduction in Ca 2ϩ release from the SR. To examine this, we subjected single fibers from both the EDL and the soleus to the leak protocol described in METHODS to determine the rate of Ca 2ϩ release from the SR under conditions of zero Ca 2ϩ uptake (see 5,8,28).…”

Section: Effect Of Various Treatments On Depolarization-induced Respomentioning

confidence: 99%

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Effects of high myoplasmic l-lactate concentration on E-C coupling in mammalian skeletal muscle

Posterino

Fryer

2000

Journal of Applied Physiology

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The effects of high myoplasmic L-lactate concentrations (20-40 mM) at constant pH (7.1) were investigated on contractile protein function, voltage-dependent Ca(2+) release, and passive Ca(2+) leak from the sarcoplasmic reticulum (SR) in mechanically skinned fast-twitch (extensor digitorum longus; EDL) and slow-twitch (soleus) fibers of the rat. L-Lactate (20 mM) significantly reduced maximum Ca(2+)-activated force by 4 +/- 0.5% (n = 5, P < 0.05) and 5 +/- 0.4% (n = 6, P < 0.05) for EDL and soleus, respectively. The Ca(2+) sensitivity was also significantly decreased by 0.06 +/- 0. 002 (n = 5, P < 0.05) and 0.13 +/- 0.01 (n = 6, P < 0.001) pCa units, respectively. Exposure to L-lactate (20 mM) for 30 s reduced depolarization-induced force responses by ChCl substitution by 7 +/- 3% (n = 17, P < 0.05). This inhibition was not obviously affected by the presence of the lactate transport blocker quercetin (10 microM), or the chloride channel blocker anthracene-9-carboxylic acid (100 microM). L-Lactate (20 mM) increased passive Ca(2+) leak from the SR in EDL fibers (the integral of the response to caffeine was reduced by 16 +/- 5%, n = 9, P < 0.05) with no apparent effect in soleus fibers (100 +/- 2%, n = 3). These results indicate that the L-lactate ion per se has negligible effects on either voltage-dependent Ca(2+) release or SR Ca(2+) handling and exerts only a modest inhibitory effect on muscle contractility at the level of the contractile proteins.

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Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Effect Of Various Treatments On Depolarization-induced Respomentioning

confidence: 99%

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Effects of high myoplasmic l-lactate concentration on E-C coupling in mammalian skeletal muscle

Posterino

Fryer

2000

Journal of Applied Physiology

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“…The concept of a counterion channel in the ER to balance negative charges occurring through Ca 2+ release and reuptake into the ER store has long been proposed [7]. In the SR, Cl − channels play an essential role in excitation-contraction coupling, by balancing charge movement during calcium release and reuptake [13,22]. This has also been well described in airway smooth muscle cells.…”

Section: Bestrophin 1 Controls Intracellular Ca 2+ Signalsmentioning

confidence: 96%

ER-localized bestrophin 1 activates Ca2+-dependent ion channels TMEM16A and SK4 possibly by acting as a counterion channel

Barro-Soria

Aldehni

Almaça

et al. 2009

Pflugers Arch - Eur J Physiol

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Bestrophins form Ca(2+)-activated Cl(-) channels and regulate intracellular Ca(2+) signaling. We demonstrate that bestrophin 1 is localized in the endoplasmic reticulum (ER), where it interacts with stromal interacting molecule 1, the ER-Ca(2+) sensor. Intracellular Ca(2+) transients elicited by stimulation of purinergic P2Y(2) receptors in HEK293 cells were augmented by hBest1. The p21-activated protein kinase Pak2 was found to phosphorylate hBest1, thereby enhancing Ca(2+) signaling and activation of Ca(2+)-dependent Cl(-) (TMEM16A) and K(+) (SK4) channels. Lack of bestrophin 1 expression in respiratory epithelial cells of mBest1 knockout mice caused expansion of ER cisterns and induced Ca(2+) deposits. hBest1 is, therefore, important for Ca(2+) handling of the ER store and may resemble the long-suspected counterion channel to balance transient membrane potentials occurring through inositol triphosphate (IP(3))-induced Ca(2+) release and store refill. Thus, bestrophin 1 regulates compartmentalized Ca(2+) signaling that plays an essential role in Best macular dystrophy, inflammatory diseases such as cystic fibrosis, as well as proliferation.

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“…The effect could be attributed predominantly to the Clions and may reflect increased leakiness of the sarcoplasmic reticulum caused by Cl - [1]. The diffusion of KCl into the fibre pools led to a rapid run down of the cells.…”

Section: Discussionmentioning

confidence: 98%

Tools for flash-photolysis experiments on voltage-clamped muscle fibre segments

Schuhmeier

Tewes

Szentesi

et al. 2000

Pfl�gers Archiv European Journal of Physiology

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An experimental set-up is described that allows the combination of rapid transmembrane voltage changes and photometric calcium recording with the fast photochemical turnover of substances applied externally or intracellularly to cut skeletal muscle fibres. It consists of a double-vaseline-gap system, designed for use with a xenon-flash-lamp device and a dual-wavelength microscope photometer. The pools of the vaseline gap chamber that contain the solutions surrounding the cut ends and the voltage-clamped segment of the muscle fibre are closed and have volumes of 20-50 microl. Thin tubes allow rapid solution change or continuous perfusion in the chamber compartments. Accessory tools were constructed to simplify focussing and measuring the flash-light intensity. A pilot light delivered from a red laser diode is used as a guide beam to target the ultraviolet (UV) flash to the preparation. The light distribution in the focal region and the relative changes in flash intensity with increasing numbers of flashes were quantified with an instrument that integrates the photo-current of a UV-sensitive silicon diode. The function of the set-up was demonstrated by measuring the efficiency of Ca2+ release from DM-nitrophen in quartz capillaries using the Ca(2+)-sensitive dye antipyrylazo III and by recording the flash-induced recovery of L-type calcium currents in muscle fibres blocked by the light-sensitive dihydropyridine drug nifedipine.

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Effect of chloride on Ca 2+ release from the sarcoplasmic reticulum of mechanically skinned skeletal muscle fibres

Cited by 18 publications

References 35 publications

Effects of high myoplasmic l-lactate concentration on E-C coupling in mammalian skeletal muscle

Effects of high myoplasmic l-lactate concentration on E-C coupling in mammalian skeletal muscle

ER-localized bestrophin 1 activates Ca2+-dependent ion channels TMEM16A and SK4 possibly by acting as a counterion channel

Tools for flash-photolysis experiments on voltage-clamped muscle fibre segments

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