Premium
The effects of removing external sodium upon the control of potassium (86Rb+) permeability in the isolated human sweat gland
Author(s) -
Wilson SM,
Bovell DL,
Elder HY,
Jenkinson DM,
Pediani JD
Publication year - 1990
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1990.sp003443
Subject(s) - potassium , chemistry , calcium , sodium , endocrinology , medicine , acetylcholine , bicarbonate , stimulation , sweat , permeability (electromagnetism) , cholinergic , biophysics , biochemistry , membrane , biology , organic chemistry
The changes in cytoplasmic free calcium ([Ca2+]i) which occur in isolated human sweat glands during cholinergic stimulation have been studied indirectly by monitoring potassium permeability. The acetylcholine‐evoked permeability increase normally consists of transient and sustained phases which are attributed to the mobilization of intracellular calcium stores and to calcium influx respectively. Such consistent responses to acetylcholine could not be obtained during superfusion with bicarbonate‐free, HEPES‐buffered solutions. The human sweat gland in vitro therefore appears to have a strict requirement for bicarbonate. The sustained component of the response was not affected by total removal of external sodium, suggesting that calcium influx does not occur via a sodium‐dependent system. The transient component, however, was abolished when external sodium was replaced by N‐methyl‐D‐glucammonium (NMDG+). It therefore appears that secretagogue‐evoked mobilization of cytoplasmic calcium is dependent, in some way, upon external sodium. This dependence is not, however, absolute as the response was essentially normal when sodium was replaced by lithium.