|
|
|
|
|
|
|
||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The Journal of General Physiology, Vol 91, 73-106, Copyright © 1988 by The Rockefeller University Press
ARTICLES |
T Hoshi and RW Aldrich
Department of Neurobiology, Stanford University School of Medicine, California 94305.
Properties of the whole-cell K+ currents and voltage-dependent activation and inactivation properties of single K+ channels in clonal pheochromocytoma (PC-12) cells were studied using the patch-clamp recording technique. Depolarizing pulses elicited slowly inactivating whole-cell K+ currents, which were blocked by external application of tetraethylammonium+, 4-aminopyridine, and quinidine. The amplitudes and time courses of these K+ currents were largely independent of the prepulse voltage. Although pharmacological agents and manipulation of the voltage-clamp pulse protocol failed to reveal any additional separable whole-cell currents in a majority of the cells examined, single-channel recordings showed that, in addition to the large Ca++- dependent K+ channels described previously in many other preparations, PC-12 cells had at least four distinct types of K+ channels activated by depolarization. These four types of K+ channels differed in the open- channel current-voltage relation, time course of activation and inactivation, and voltage dependence of activation and inactivation. These K+ channels were designated the Kw, Kz, Ky, and Kx channels. The typical chord conductances of these channels were 18, 12, 7, and 7 pS in the excised configuration using Na+-free saline solutions. These four types of K+ channels opened in the presence of low concentrations of internal Ca++ (1 nM). Their voltage-dependent gating properties can account for the properties of the whole-cell K+ currents in PC-12 cells.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  C.-X. Fan, X.-K. Chen, C. Zhang, L.-X. Wang, K.-L. Duan, L.-L. He, Y. Cao, S.-Y. Liu, M.-N. Zhong, C. Ulens, et al. A Novel Conotoxin from Conus betulinus, kappa -BtX, Unique in Cysteine Pattern and in Function as a Specific BK Channel Modulator J. Biol. Chem., April 4, 2003; 278(15): 12624 - 12633. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Savic, P. Pedarzani, and M. Sciancalepore Medium Afterhyperpolarization and Firing Pattern Modulation in Interneurons of Stratum Radiatum in the CA3 Hippocampal Region J Neurophysiol, May 1, 2001; 85(5): 1986 - 1997. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Chabbert, J. M. Chambard, A. Sans, and G. Desmadryl Three Types of Depolarization-Activated Potassium Currents in Acutely Isolated Mouse Vestibular Neurons J Neurophysiol, March 1, 2001; 85(3): 1017 - 1026. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R.W. Aldrich, T. Hoshi, and W.N. Zagotta Differences in Gating among Amino-terminal Variants of Shaker Potassium Channels Cold Spring Harb Symp Quant Biol, January 1, 1990; 55(0): 19 - 27. [Abstract] [PDF]
|
|
|
|
 |
|
 D. Yue, J. Lawrence, and E Marban Two molecular transitions influence cardiac sodium channel gating Science, April 21, 1989; 244(4902): 349 - 352. [Abstract] [PDF]
|
|
|
|
|
|
T Hoshi, S. Garber, and R. Aldrich Effect of forskolin on voltage-gated K+ channels is independent of adenylate cyclase activation Science, June 17, 1988; 240(4859): 1652 - 1655. [Abstract] [PDF]
|
|
|
|
