Abstract
1. Kinetic states and modes of a large-conductance Ca2+-activated K+ channel in excised patches of membrane from cultured rat skeletal muscle were studied with the patch clamp technique. Up to 10(6) open and shut intervals were analysed from each of seven different excised membrane patches containing a single channel. 2. Plots of the mean durations of consecutive groups of ten to fifty open and shut intervals were made to assess kinetic stability of the channel. Occasional abrupt decreases in the mean open interval duration from normal to different distinct levels, which were maintained for hundreds to thousands of consecutive intervals, indicated entry of the channel into different modes. 3. Four different kinetic modes were identified: normal mode, which included 96% of the intervals; intermediate open mode with 3.2% of the intervals; brief open mode with 0.5% of the intervals; and buzz mode with 0.1% of the intervals. The mean open interval durations were 61% of normal during the intermediate open mode, 12% of normal during the brief open mode, and 2.6% of normal during the buzz mode. 4. Most mode transitions were observed from the normal mode to one of the other modes and then back to normal. Sojourns in the normal mode lasted 5-1000 s. Sojourns in the intermediate open, brief open, and buzz modes lasted 1.5-150, 1-7, and 0.01-1 s, respectively. 5. During normal activity the distributions of interval durations were typically described by the sum of three to four exponential components for the open intervals and six to eight exponential components for the shut intervals, and this was the case for data obtained over a wide range of open channel probability resulting from different Ca2+i. These observations suggest that the channel can enter at least three to four open and six to eight shut states during normal activity. 6. The numbers of detected states for data sets of different sample sizes drawn from normal activity agreed with theoretical predictions, and were essentially independent of the segment of normal activity from which the data sets were drawn. These observations are consistent with relative stability of channel kinetics during normal activity. Detection of each additional open or shut state after the first was found to require a 3- to 10-fold increase in the number of analysed events. 7. The intermediate open mode differed from the normal mode in that the longest open component of the four normal open components was absent.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- Adams P. R., Constanti A., Brown D. A., Clark R. B. Intracellular Ca2+ activates a fast voltage-sensitive K+ current in vertebrate sympathetic neurones. Nature. 1982 Apr 22;296(5859):746–749. doi: 10.1038/296746a0. [DOI] [PubMed] [Google Scholar]
- Ansari A., Berendzen J., Bowne S. F., Frauenfelder H., Iben I. E., Sauke T. B., Shyamsunder E., Young R. D. Protein states and proteinquakes. Proc Natl Acad Sci U S A. 1985 Aug;82(15):5000–5004. doi: 10.1073/pnas.82.15.5000. [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]
- Bers D. M. A simple method for the accurate determination of free [Ca] in Ca-EGTA solutions. Am J Physiol. 1982 May;242(5):C404–C408. doi: 10.1152/ajpcell.1982.242.5.C404. [DOI] [PubMed] [Google Scholar]
- Bezanilla F., Armstrong C. M. Inactivation of the sodium channel. I. Sodium current experiments. J Gen Physiol. 1977 Nov;70(5):549–566. doi: 10.1085/jgp.70.5.549. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blatz A. L., Magleby K. L. Correcting single channel data for missed events. Biophys J. 1986 May;49(5):967–980. doi: 10.1016/S0006-3495(86)83725-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blatz A. L., Magleby K. L. Ion conductance and selectivity of single calcium-activated potassium channels in cultured rat muscle. J Gen Physiol. 1984 Jul;84(1):1–23. doi: 10.1085/jgp.84.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blatz A. L., Magleby K. L. Quantitative description of three modes of activity of fast chloride channels from rat skeletal muscle. J Physiol. 1986 Sep;378:141–174. doi: 10.1113/jphysiol.1986.sp016212. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Careri G., Fasella P., Gratton E. Statistical time events in enzymes: a physical assessment. CRC Crit Rev Biochem. 1975 Aug;3(2):141–164. doi: 10.3109/10409237509102555. [DOI] [PubMed] [Google Scholar]
- Colquhoun D., Hawkes A. G. On the stochastic properties of single ion channels. Proc R Soc Lond B Biol Sci. 1981 Mar 6;211(1183):205–235. doi: 10.1098/rspb.1981.0003. [DOI] [PubMed] [Google Scholar]
- DEL CASTILLO J., KATZ B. Interaction at end-plate receptors between different choline derivatives. Proc R Soc Lond B Biol Sci. 1957 May 7;146(924):369–381. doi: 10.1098/rspb.1957.0018. [DOI] [PubMed] [Google Scholar]
- Finer-Moore J., Stroud R. M. Amphipathic analysis and possible formation of the ion channel in an acetylcholine receptor. Proc Natl Acad Sci U S A. 1984 Jan;81(1):155–159. doi: 10.1073/pnas.81.1.155. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gallin E. K. Calcium- and voltage-activated potassium channels in human macrophages. Biophys J. 1984 Dec;46(6):821–825. doi: 10.1016/S0006-3495(84)84080-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Golowasch J., Kirkwood A., Miller C. Allosteric effects of Mg2+ on the gating of Ca2+-activated K+ channels from mammalian skeletal muscle. J Exp Biol. 1986 Sep;124:5–13. doi: 10.1242/jeb.124.1.5. [DOI] [PubMed] [Google Scholar]
- Gray P. T., Bevan S., Ritchie J. M. High conductance anion-selective channels in rat cultured Schwann cells. Proc R Soc Lond B Biol Sci. 1984 Jun 22;221(1225):395–409. doi: 10.1098/rspb.1984.0041. [DOI] [PubMed] [Google Scholar]
- Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [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]
- Horn R., Lange K. Estimating kinetic constants from single channel data. Biophys J. 1983 Aug;43(2):207–223. doi: 10.1016/S0006-3495(83)84341-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horn R. Statistical methods for model discrimination. Applications to gating kinetics and permeation of the acetylcholine receptor channel. Biophys J. 1987 Feb;51(2):255–263. doi: 10.1016/S0006-3495(87)83331-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Illingworth J. A. A common source of error in pH measurements. Biochem J. 1981 Apr 1;195(1):259–262. doi: 10.1042/bj1950259. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Latorre R., Vergara C., Hidalgo C. Reconstitution in planar lipid bilayers of a Ca2+-dependent K+ channel from transverse tubule membranes isolated from rabbit skeletal muscle. Proc Natl Acad Sci U S A. 1982 Feb;79(3):805–809. doi: 10.1073/pnas.79.3.805. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Liebovitch L. S., Fischbarg J., Koniarek J. P., Todorova I., Wang M. Fractal model of ion-channel kinetics. Biochim Biophys Acta. 1987 Jan 26;896(2):173–180. doi: 10.1016/0005-2736(87)90177-5. [DOI] [PubMed] [Google Scholar]
- Magleby K. L., Pallotta B. S. Burst kinetics of single calcium-activated potassium channels in cultured rat muscle. J Physiol. 1983 Nov;344:605–623. doi: 10.1113/jphysiol.1983.sp014958. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Magleby K. L., Pallotta B. S. Calcium dependence of open and shut interval distributions from calcium-activated potassium channels in cultured rat muscle. J Physiol. 1983 Nov;344:585–604. doi: 10.1113/jphysiol.1983.sp014957. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marty A. Blocking of large unitary calcium-dependent potassium currents by internal sodium ions. Pflugers Arch. 1983 Feb;396(2):179–181. doi: 10.1007/BF00615524. [DOI] [PubMed] [Google Scholar]
- Marty A. Ca-dependent K channels with large unitary conductance in chromaffin cell membranes. Nature. 1981 Jun 11;291(5815):497–500. doi: 10.1038/291497a0. [DOI] [PubMed] [Google Scholar]
- McManus O. B., Blatz A. L., Magleby K. L. Inverse relationship of the durations of adjacent open and shut intervals for C1 and K channels. Nature. 1985 Oct 17;317(6038):625–627. doi: 10.1038/317625a0. [DOI] [PubMed] [Google Scholar]
- McManus O. B., Blatz A. L., Magleby K. L. Sampling, log binning, fitting, and plotting durations of open and shut intervals from single channels and the effects of noise. Pflugers Arch. 1987 Nov;410(4-5):530–553. doi: 10.1007/BF00586537. [DOI] [PubMed] [Google Scholar]
- Methfessel C., Boheim G. The gating of single calcium-dependent potassium channels is described by an activation/blockade mechanism. Biophys Struct Mech. 1982;9(1):35–60. doi: 10.1007/BF00536014. [DOI] [PubMed] [Google Scholar]
- Miller D. J., Smith G. L. EGTA purity and the buffering of calcium ions in physiological solutions. Am J Physiol. 1984 Jan;246(1 Pt 1):C160–C166. doi: 10.1152/ajpcell.1984.246.1.C160. [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]
- Neher E., Stevens C. F. Conductance fluctuations and ionic pores in membranes. Annu Rev Biophys Bioeng. 1977;6:345–381. doi: 10.1146/annurev.bb.06.060177.002021. [DOI] [PubMed] [Google Scholar]
- Noda M., Shimizu S., Tanabe T., Takai T., Kayano T., Ikeda T., Takahashi H., Nakayama H., Kanaoka Y., Minamino N. Primary structure of Electrophorus electricus sodium channel deduced from cDNA sequence. Nature. 1984 Nov 8;312(5990):121–127. doi: 10.1038/312121a0. [DOI] [PubMed] [Google Scholar]
- Pallotta B. S. Calcium-activated potassium channels in rat muscle inactivate from a short-duration open state. J Physiol. 1985 Jun;363:501–516. doi: 10.1113/jphysiol.1985.sp015724. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pallotta B. S., Magleby K. L., Barrett J. N. Single channel recordings of Ca2+-activated K+ currents in rat muscle cell culture. Nature. 1981 Oct 8;293(5832):471–474. doi: 10.1038/293471a0. [DOI] [PubMed] [Google Scholar]
- Pallotta B. S. N-bromoacetamide removes a calcium-dependent component of channel opening from calcium-activated potassium channels in rat skeletal muscle. J Gen Physiol. 1985 Nov;86(5):601–611. doi: 10.1085/jgp.86.5.601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Patlak J. B., Gration K. A., Usherwood P. N. Single glutamate-activated channels in locust muscle. Nature. 1979 Apr 12;278(5705):643–645. doi: 10.1038/278643a0. [DOI] [PubMed] [Google Scholar]
- Patlak J. B., Ortiz M. Slow currents through single sodium channels of the adult rat heart. J Gen Physiol. 1985 Jul;86(1):89–104. doi: 10.1085/jgp.86.1.89. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Petersen O. H., Maruyama Y. Calcium-activated potassium channels and their role in secretion. Nature. 1984 Feb 23;307(5953):693–696. doi: 10.1038/307693a0. [DOI] [PubMed] [Google Scholar]
- Roux B., Sauvé R. A general solution to the time interval omission problem applied to single channel analysis. Biophys J. 1985 Jul;48(1):149–158. doi: 10.1016/S0006-3495(85)83768-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vergara C., Latorre R. Kinetics of Ca2+-activated K+ channels from rabbit muscle incorporated into planar bilayers. Evidence for a Ca2+ and Ba2+ blockade. J Gen Physiol. 1983 Oct;82(4):543–568. doi: 10.1085/jgp.82.4.543. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wong B. S., Lecar H., Adler M. Single calcium-dependent potassium channels in clonal anterior pituitary cells. Biophys J. 1982 Sep;39(3):313–317. doi: 10.1016/S0006-3495(82)84522-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yellen G. Ionic permeation and blockade in Ca2+-activated K+ channels of bovine chromaffin cells. J Gen Physiol. 1984 Aug;84(2):157–186. doi: 10.1085/jgp.84.2.157. [DOI] [PMC free article] [PubMed] [Google Scholar]