The characterization of the increase of membrane conductance after depolarization in single rat adrenal chromaffin cells.
- Author:
Wonil LIM
1
;
Sang Jeong KIM
;
Jun KIM
Author Information
1. Department of Physiology & Biophysics, Seoul National University, College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-799, Korea.
- Publication Type:Original Article
- Keywords:
Chromaffin cell;
Small conductance calcium-activated potassium channel;
Patch-clamp techniques;
Membrane conductance;
Membrane capacitance
- MeSH:
Animals;
Apamin;
Calcium;
Chromaffin Cells*;
Exocytosis;
Membranes*;
Patch-Clamp Techniques;
Permeability;
Rats*;
Tubocurarine
- From:The Korean Journal of Physiology and Pharmacology
1998;2(1):95-100
- CountryRepublic of Korea
- Language:English
-
Abstract:
The conductance change evoked by step depolarization was studied in primarily cultured rat adrenal chromaffin cells using patch-clamp and capacitance measurement techniques. When we applied a depolarizing pulse to a chromaffin cell, the inward calcium current was followed by an outward current and depolarization-induced exocytosis was accompanied by an increase in conductance trace. The slow inward tail current which has the same time course as the conductance change was observed in current recording. The activation of slow tail current was calcium-dependent. Reversal potentials agreed with Nernst equation assuming relative permeability of Cs+ to K+ is 0.095. The outward current and tail current were blocked by apamin (200 nM) and d-tubocurarine (2 mM). The conductance change was blocked by apamin and did not affect membrane capacitance recording. We confirmed that conductance change after depolarization comes from the activation of the SK channel and can be blocked by application of the SK channel blockers. Consequently, it is necessary to consider blocking of the SK channel during membrane capacitance recording.
