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Temperature Dependence of Catecholamine Secretion from Cultured Bovine Chromaffin Cells
Author(s) -
Kao LungSen,
Westhead Edward W.
Publication year - 1984
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1984.tb00940.x
Subject(s) - carbachol , catecholamine , acetylcholine , medicine , endocrinology , secretion , chemistry , arrhenius plot , epinephrine , cholinergic , chromaffin cell , stimulation , biology , adrenal medulla , activation energy , organic chemistry
Secretion of both epinephrine and norepinephrine by cultured chromaffin cells was studied at temperatures ranging from 0°C to 37°C. The percentage of epinephrine secreted was always lower than that of norepinephrine when the cells were stimulated with either acetylcholine or high K + at any temperature. When the cells were stimulated with acetylcholine or carbachol the percentage of catecholamine secreted at 10 min increased with temperature from 4°C to 24°C and then decreased from 24°C to 37°C. Potassium‐stimulated cells secreted increasing amounts of catecholamine as the temperature was increased to 37°C. We found, however, that the initial rates of secretion increased continuously as temperature increased throughout the range for both carbachol‐and K + ‐stimulated cells. The temperature maximum of acetylcholine‐stimulated secretion is caused by a faster shut‐off of secretion at higher temperature. The Arrhenius plots of initial rates show an inflection point at approximately 17°C for carbachol‐stimulated cells. The plot for K + ‐stimulated cells is a straight line over the entire temperature range. The transition could be caused by a conformational change in the cholinergic receptor/ion channel molecule.