Abstract
A high-conductance (100 pS in 53 mM trans Ca2+) Ca2+ channel was incorporated from heavy-density skeletal muscle sarcoplasmic reticulum (SR) fractions into planar lipid bilayers of the Mueller-Rudin type. cis Ca2+ in the range of 2-950 microM increased open probability (Po) in single channel records without affecting open event lifetimes. Millimolar ATP was found to be as good as or better than Ca2+ in activation; however, both Ca2+ and ATP were required to fully activate the channel, i.e., to bring Po = 1. Exponential fits to open and closed single channel lifetimes suggested that the channel may exist in many distinct states. Two open and two closed states were identified when the channel was activated by either Ca2+ or ATP alone or by Ca2+ plus nucleotide. Mg2+ was found to permeate the SR Ca channel in a trans-to- cis direction such that iMg2+/iCa2+ = 0.40. cis Mg2+ was inhibitory and in single channel recordings produced an unresolvable flickering of Ca- and nucleotide-activated channels. At nanomolar cis Ca2+, 4 microM Mg2+ completely inhibited nucleotide-activated channels. In the presence of 2 microM cis Ca2+, the nucleotide-activated macroscopic Ba conductance was inhibited by cis Mg2+ with an IC50 equal to 1.5 mM.
Full Text
The Full Text of this article is available as a PDF (866.1 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Affolter H., Coronado R. Agonists Bay-K8644 and CGP-28392 open calcium channels reconstituted from skeletal muscle transverse tubules. Biophys J. 1985 Aug;48(2):341–347. doi: 10.1016/S0006-3495(85)83789-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Almers W., Palade P. T. Slow calcium and potassium currents across frog muscle membrane: measurements with a vaseline-gap technique. J Physiol. 1981 Mar;312:159–176. doi: 10.1113/jphysiol.1981.sp013622. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Barrett J. N., Magleby K. L., Pallotta B. S. Properties of single calcium-activated potassium channels in cultured rat muscle. J Physiol. 1982 Oct;331:211–230. doi: 10.1113/jphysiol.1982.sp014370. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brown A. M., Wilson D. L., Lux H. D. Activation of calcium channels. Biophys J. 1984 Jan;45(1):125–127. doi: 10.1016/S0006-3495(84)84134-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ehrenstein G., Blumenthal R., Latorre R., Lecar H. Kinetics of the opening and closing of individual excitability-inducing material channels in a lipid bilayer. J Gen Physiol. 1974 Jun;63(6):707–721. doi: 10.1085/jgp.63.6.707. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Endo M. Calcium release from the sarcoplasmic reticulum. Physiol Rev. 1977 Jan;57(1):71–108. doi: 10.1152/physrev.1977.57.1.71. [DOI] [PubMed] [Google Scholar]
- Fabiato A. Myoplasmic free calcium concentration reached during the twitch of an intact isolated cardiac cell and during calcium-induced release of calcium from the sarcoplasmic reticulum of a skinned cardiac cell from the adult rat or rabbit ventricle. J Gen Physiol. 1981 Nov;78(5):457–497. doi: 10.1085/jgp.78.5.457. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fabiato A. Time and calcium dependence of activation and inactivation of calcium-induced release of calcium from the sarcoplasmic reticulum of a skinned canine cardiac Purkinje cell. J Gen Physiol. 1985 Feb;85(2):247–289. doi: 10.1085/jgp.85.2.247. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hess P., Lansman J. B., Tsien R. W. Different modes of Ca channel gating behaviour favoured by dihydropyridine Ca agonists and antagonists. Nature. 1984 Oct 11;311(5986):538–544. doi: 10.1038/311538a0. [DOI] [PubMed] [Google Scholar]
- Ikemoto N., Antoniu B., Mészáros L. G. Rapid flow chemical quench studies of calcium release from isolated sarcoplasmic reticulum. J Biol Chem. 1985 Nov 15;260(26):14096–14100. [PubMed] [Google Scholar]
- Kirino Y., Osakabe M., Shimizu H. Ca2+-induced Ca2+ release from fragmented sarcoplasmic reticulum: Ca2+-dependent passive Ca2+ efflux. J Biochem. 1983 Oct;94(4):1111–1118. doi: 10.1093/oxfordjournals.jbchem.a134454. [DOI] [PubMed] [Google Scholar]
- Martonosi A. N. Mechanisms of Ca2+ release from sarcoplasmic reticulum of skeletal muscle. Physiol Rev. 1984 Oct;64(4):1240–1320. doi: 10.1152/physrev.1984.64.4.1240. [DOI] [PubMed] [Google Scholar]
- Meissner G. Adenine nucleotide stimulation of Ca2+-induced Ca2+ release in sarcoplasmic reticulum. J Biol Chem. 1984 Feb 25;259(4):2365–2374. [PubMed] [Google Scholar]
- Meissner G., Darling E., Eveleth J. Kinetics of rapid Ca2+ release by sarcoplasmic reticulum. Effects of Ca2+, Mg2+, and adenine nucleotides. Biochemistry. 1986 Jan 14;25(1):236–244. doi: 10.1021/bi00349a033. [DOI] [PubMed] [Google Scholar]
- Meissner G. Monovalent ion and calcium ion fluxes in sarcoplasmic reticulum. Mol Cell Biochem. 1983;55(1):65–82. doi: 10.1007/BF00229243. [DOI] [PubMed] [Google Scholar]
- Miller C. Voltage-gated cation conductance channel from fragmented sarcoplasmic reticulum: steady-state electrical properties. J Membr Biol. 1978 Apr 20;40(1):1–23. doi: 10.1007/BF01909736. [DOI] [PubMed] [Google Scholar]
- Moczydlowski E., Latorre R. Gating kinetics of Ca2+-activated K+ channels from rat muscle incorporated into planar lipid bilayers. Evidence for two voltage-dependent Ca2+ binding reactions. J Gen Physiol. 1983 Oct;82(4):511–542. doi: 10.1085/jgp.82.4.511. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nagasaki K., Kasai M. Channel selectivity and gating specificity of calcium-induced calcium release channel in isolated sarcoplasmic reticulum. J Biochem. 1984 Dec;96(6):1769–1775. doi: 10.1093/oxfordjournals.jbchem.a135009. [DOI] [PubMed] [Google Scholar]
- Nagasaki K., Kasai M. Fast release of calcium from sarcoplasmic reticulum vesicles monitored by chlortetracycline fluorescence. J Biochem. 1983 Oct;94(4):1101–1109. doi: 10.1093/oxfordjournals.jbchem.a134453. [DOI] [PubMed] [Google Scholar]
- Smith J. S., Coronado R., Meissner G. Sarcoplasmic reticulum contains adenine nucleotide-activated calcium channels. Nature. 1985 Aug 1;316(6027):446–449. doi: 10.1038/316446a0. [DOI] [PubMed] [Google Scholar]
- Somlyo A. P. The messenger across the gap. Nature. 1985 Jul 25;316(6026):298–299. doi: 10.1038/316298b0. [DOI] [PubMed] [Google Scholar]
- Vergara J., Tsien R. Y., Delay M. Inositol 1,4,5-trisphosphate: a possible chemical link in excitation-contraction coupling in muscle. Proc Natl Acad Sci U S A. 1985 Sep;82(18):6352–6356. doi: 10.1073/pnas.82.18.6352. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Volpe P., Salviati G., Di Virgilio F., Pozzan T. Inositol 1,4,5-trisphosphate induces calcium release from sarcoplasmic reticulum of skeletal muscle. Nature. 1985 Jul 25;316(6026):347–349. doi: 10.1038/316347a0. [DOI] [PubMed] [Google Scholar]
- Yamamoto N., Kasai M. Mechanism and function of the Ca2+-gated cation channel in sarcoplasmic reticulum vesicles. J Biochem. 1982 Aug;92(2):485–496. doi: 10.1093/oxfordjournals.jbchem.a133956. [DOI] [PubMed] [Google Scholar]