HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dietze, B. Articles by Melzer, W. Search for Related Content PubMed PubMed Citation Articles by Dietze, B. Articles by Melzer, W.

Voltage-controlled Ca²⁺ release in normal and ryanodine receptor type 3 (RyR3)-deficient mouse myotubes

B. Dietze, F. Bertocchini *, V. Barone *, A. Struk, V. Sorrentino *¹ and W. Melzer

Primary cultured myotubes were derived from satellite cells of the diaphragm obtained from both normal mice (RyR3+/+) and mice with a targeted mutation eliminating expression of the type 3 isoform of the ryanodine receptor (RyR3-/-). Using the whole-cell patch clamp technique, L-type Ca²⁺ currents were measured during step depolarizations. Simultaneously, intracellular Ca²⁺ transients were recorded with the fluorescent indicator dye fura-2.

After correction for non-instantaneous binding of Ca²⁺ to the indicator dye and taking into account the dynamics of Ca²⁺ binding to intracellular constituents, an estimate of the time course of the Ca²⁺ release rate from the sarcoplasmic reticulum (SR) was obtained.

The calculated SR Ca²⁺ release flux exhibited a marked peak within less than 12 ms after the onset of the voltage-clamp depolarization and fell rapidly thereafter to a five times lower, almost steady level. It declined rapidly after termination of the depolarization.

Signals in normal and RyR3-deficient myotubes showed no significant difference in the activation of Ca²⁺ conductance and in amplitude, time course and voltage dependence of the Ca²⁺ efflux from the SR.

In conclusion, the characteristics of voltage-controlled Ca²⁺ release reported here are similar to those of mature mammalian muscle fibres. In contrast to differences observed in the contractile properties of RyR3-deficient muscle fibres, a contribution of RyR3 to excitation-contraction coupling could not be detected in myotubes.

This article has been cited by other articles:

				C. Legrand, E. Giacomello, C. Berthier, B. Allard, V. Sorrentino, and V. Jacquemond Spontaneous and voltage-activated Ca2+ release in adult mouse skeletal muscle fibres expressing the type 3 ryanodine receptor J. Physiol., January 15, 2008; 586(2): 441 - 457. [Abstract] [Full Text] [PDF]

				R. P. Schuhmeier, E. Gouadon, D. Ursu, N. Kasielke, B. E. Flucher, M. Grabner, and W. Melzer Functional Interaction of CaV Channel Isoforms with Ryanodine Receptors Studied in Dysgenic Myotubes Biophys. J., March 1, 2005; 88(3): 1765 - 1777. [Abstract] [Full Text] [PDF]

				C. F. Perez, J. R. Lopez, and P. D. Allen Expression levels of RyR1 and RyR3 control resting free Ca2+ in skeletal muscle Am J Physiol Cell Physiol, March 1, 2005; 288(3): C640 - C649. [Abstract] [Full Text] [PDF]

				D. Ursu, R. P. Schuhmeier, and W. Melzer Voltage-controlled Ca2+ release and entry flux in isolated adult muscle fibres of the mouse J. Physiol., January 15, 2005; 562(2): 347 - 365. [Abstract] [Full Text] [PDF]

				R.P. Schuhmeier and W. Melzer Voltage-dependent Ca2+ Fluxes in Skeletal Myotubes Determined Using a Removal Model Analysis J. Gen. Physiol., December 29, 2003; 123(1): 33 - 52. [Abstract] [Full Text] [PDF]

				N. Kasielke, G. J. Obermair, G. Kugler, M. Grabner, and B. E. Flucher Cardiac-type EC-Coupling in Dysgenic Myotubes Restored with Ca2+ Channel Subunit Isoforms {alpha}1C and {alpha}1D Does not Correlate with Current Density Biophys. J., June 1, 2003; 84(6): 3816 - 3828. [Abstract] [Full Text] [PDF]

				R. P. Schuhmeier, B. Dietze, D. Ursu, F. Lehmann-Horn, and W. Melzer Voltage-Activated Calcium Signals in Myotubes Loaded with High Concentrations of EGTA Biophys. J., February 1, 2003; 84(2): 1065 - 1078. [Abstract] [Full Text] [PDF]

				D. Yang, Z. Pan, H. Takeshima, C. Wu, R. Y. Nagaraj, J. Ma, and H. Cheng RyR3 Amplifies RyR1-mediated Ca2+-induced Ca2+ Release in Neonatal Mammalian Skeletal Muscle J. Biol. Chem., October 19, 2001; 276(43): 40210 - 40214. [Abstract] [Full Text] [PDF]

				R. Rossi, R. Bottinelli, V. Sorrentino, and C. Reggiani Response to caffeine and ryanodine receptor isoforms in mouse skeletal muscles Am J Physiol Cell Physiol, August 1, 2001; 281(2): C585 - C594. [Abstract] [Full Text] [PDF]

				J. S. Clancy, H. Takeshima, S. L. Hamilton, and M. B. Reid Contractile function is unaltered in diaphragm from mice lacking calcium release channel isoform 3 Am J Physiol Regulatory Integrative Comp Physiol, October 1, 1999; 277(4): R1205 - R1209. [Abstract] [Full Text] [PDF]