Two mechanisms for inward rectification of current flow through the purinoceptor P2X2 class of ATP-gated channels

被引:37
作者
Zhou, Z [1 ]
Hume, RI [1 ]
机构
[1] Univ Michigan, Dept Biol, Ann Arbor, MI 48109 USA
来源
JOURNAL OF PHYSIOLOGY-LONDON | 1998年 / 507卷 / 02期
关键词
D O I
10.1111/j.1469-7793.1998.353bt.x
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
1. The ATP receptor subunit P2X(2) was expressed in Xenopus oocytes and human embryonic kidney (HEK) 293 cells. ATP-activated currents were studied with two-electrode voltage clamp recordings from oocytes, whole-cell recordings from HEK 293 cells, and outside-out patch clamp recordings from both cell types. The steady-state current-voltage (I-V) relation showed profound inward rectification in all recording configurations. 2. Recordings from outside-out patches demonstrated that inward rectification does not require intracellular Mg2+ or polyamines, and that inward rectification was present when the same solution was used on both sides of the patch. 3. Voltage jump experiments were performed to evaluate the voltage dependence of channel gating. After fast voltage jumps, instantaneous current jumps were followed by substantial relaxations to the steady state. The time course of the current relaxations could be fitted by single exponential functions. The instantaneous I-V relation was less inwardly rectifying than the steady-state I-V relation; however, it was not linear. 4. Single channel recordings indicated that the single channel conductance became smaller when the membrane potential became more positive. This decrease could quantitatively account for inward rectification of the instantaneous I-V relation. 5. We conclude that inward rectification of P2X(2) is due to two mechanisms: voltage-dependent gating and voltage dependence of the single channel conductance.
引用
收藏
页码:353 / 364
页数:12
相关论文
共 37 条
[11]   Single channel properties of ATP-gated cation channels (P2X receptors) heterologously expressed in Chinese hamster ovary cells [J].
Evans, RJ .
NEUROSCIENCE LETTERS, 1996, 212 (03) :212-214
[12]   Ionic permeability of, and divalent cation effects on, two ATP-gated cation channels (P2X receptors) expressed in mammalian cells [J].
Evans, RJ ;
Lewis, C ;
Virginio, C ;
Lundstrom, K ;
Buell, G ;
Surprenant, A ;
North, RA .
JOURNAL OF PHYSIOLOGY-LONDON, 1996, 497 (02) :413-422
[13]   ATP MEDIATES FAST SYNAPTIC TRANSMISSION IN MAMMALIAN NEURONS [J].
EVANS, RJ ;
DERKACH, V ;
SURPRENANT, A .
NATURE, 1992, 357 (6378) :503-505
[14]   STRONG VOLTAGE-DEPENDENT INWARD RECTIFICATION OF INWARD RECTIFIER K+ CHANNELS IS CAUSED BY INTRACELLULAR SPERMINE [J].
FAKLER, B ;
BRANDLE, U ;
GLOWATZKI, E ;
WEIDEMANN, S ;
ZENNER, HP ;
RUPPERSBERG, JP .
CELL, 1995, 80 (01) :149-154
[15]   SPERMINE AND SPERMIDINE AS GATING MOLECULES FOR INWARD RECTIFIER K+ CHANNELS [J].
FICKER, E ;
TAGLIALATELA, M ;
WIBLE, BA ;
HENLEY, CM ;
BROWN, AM .
SCIENCE, 1994, 266 (5187) :1068-1072
[16]  
GEETHAHABIB M, 1990, J BIOL CHEM, V265, P13655
[17]   Potential, impedance, and rectification in membranes [J].
Goldman, DE .
JOURNAL OF GENERAL PHYSIOLOGY, 1943, 27 (01) :37-60
[18]  
Hille B., 1992, IONIC CHANNELS EXCIT
[19]   THE EFFECT OF SODIUM IONS ON THE ELECTRICAL ACTIVITY OF THE GIANT AXON OF THE SQUID [J].
HODGKIN, AL ;
KATZ, B .
JOURNAL OF PHYSIOLOGY-LONDON, 1949, 108 (01) :37-77
[20]   RECTIFICATION OF ACETYLCHOLINE-ELICITED CURRENTS IN PC12 PHEOCHROMOCYTOMA CELLS [J].
IFUNE, CK ;
STEINBACH, JH .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1990, 87 (12) :4794-4798