Fluctuation analysis of nonselective cation currents induced by AIF complex in guinea-pig chromaffin cells.
Properties of aluminium fluoride (AIF) complex-activated nonselective cation (NS) channels in guinea-pig chromaffin cells were investigated using the patch clamp technique. As the membrane potential was hyperpolarized from the holding potential of -55 mV, the AIF-induced nonselective cation current (INS) diminished progressively. With hyperpolarizations to -100 mV or more negative potentials, the AIF.INS almost instantaneously disappeared. The apparent unit conductance of AIF INS was estimated to be 3 pS by fluctuation analysis. The open state probability of AIF-activated NS channels became large with a decrease in concentration of free Mg2+ ions inside the cell and was less than 0.5 at 12 microM Mg2+. It is concluded that NS channels in the chromaffin cell apparently differ from those in smooth muscle cells.
Inoue
M
M
Department of Physiology, School of Medicine, Fukuoka University, Japan.
Imanaga
I
I
D017607:Aluminum Compounds / Q000494:pharmacology*; D000703:Analog-Digital Conversion; D000818:Animals; D002412:Cations; D019439:Chromaffin Cells / Q000187:drug effects*; D004553:Electric Conductivity; D005459:Fluorides / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000187:drug effects*; D006168:Guinea Pigs; D007473:Ion Channels / Q000187:drug effects*; D008274:Magnesium / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D018408:Patch-Clamp Techniques; D014743:Videotape Recording
D017607:Aluminum Compounds; D002412:Cations; D007473:Ion Channels; D019204:GTP-Binding Proteins; D008274:Magnesium; D005459:Fluorides; C032311:aluminum fluoride