title: Temperature sensitivity of catecholamine secretion and ion fluxes in bovine adrenal chromaffin cells.
abstract: The effects of temperature on ion fluxes and catecholamine secretion that are mediated by nicotinic acetylcholine receptors (nAChRs), voltage-sensitive calcium channels (VSCCs), and voltage-sensitive sodium channels (VSSCs) were investigated using bovine adrenal chromaffin cells. When the chromaffin cells were stimulated with DMPP, a nicotinic cholinergic agonist, or 50 mM K+, the intracellular calcium ([Ca2+]i) elevation reached a peak and decreased more slowly at lower temperatures. The DMPP-induced responses were more sensitive to temperature changes compared to high K+-induced ones. In the measurement of intracellular sodium concentrations ([Na+]i), it was found that nicotinic stimulation required a longer time to attain the maximal level of [Na+]i at lower temperatures. In addition, the VSSCs-mediated [Na+]i increase evoked by veratridine was also reduced as the temperature decreased. The measurement of [3H]norepinephrine (NE) secretion showed that the secretion within the first 3 min evoked by DMPP or high K+ was greatest at 37 degrees C. However, at 25 degrees C, the secretion evoked by DMPP, but not that by the 50 mM K+, was greater after 10 min of stimulation. This data suggest that temperature differentially affects the activity of nAChRs, VSCCs, and VSSCs, resulting in differential [Na+]i and [Ca2+]i elevation, and in the [3H]NE secretion by adrenal chromaffin cells.
authors: Department of Life Science, Pohang University of Science and Technology, Korea.
authors: T J
authors: TJ
authors: Park
authors: I S
authors: IS
authors: Lee
authors: H
authors: H
authors: Ha
authors: K T
authors: KT
authors: Kim
mesh_terms: D000311:Adrenal Glands / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism*; D007477:Ions; D009638:Norepinephrine / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism; D013696:Temperature; D014316:Tritium
chemical_list: D015220:Calcium Channels; D002395:Catecholamines; D007477:Ions; D015222:Sodium Channels; D014316:Tritium; D009638:Norepinephrine