Mechanisms involved in ATP-evoked Ca2+ oscillations in isolated human granulosa-luteal cells

Squires, Paul E. and Lee, P. S. N. and Ho Yuen, B. and Leung, P. C. K. and Buchen, A. M. J. (1997) Mechanisms involved in ATP-evoked Ca2+ oscillations in isolated human granulosa-luteal cells. Cell Calcium, 21 (5). pp. 365-374. ISSN 0143-4160

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Item Type:Article
Item Status:Live Archive

Abstract

Using single-cell microfluorimetry, we have shown that ATP evoked repetitive Ca2+ oscillations in intact Fura-2 loaded human granulosa-luteal cells (hG/LCs) in the absence of extracellular Ca2+. Sustained increases in Ca2+(i) required extracellular Ca2+ and ATP depleted stores were refreshed by brief (2 min) incubation with external Ca2+. Basal Ca2+(i) was unaffected by caffeine (1 mM), but 20 mM caffeine inhibited ATP-evoked Ca2+ release in the absence of external Ca2+. Thimerosal (10 μM) evoked repetitive Ca2+ spikes, under Ca2+-free conditions, which fused to form an elevated plateau when external Ca2+ was replaced. Thimerosal-induced changes in Ca2+(i) were reversibly inhibited by the thiol reducing agent dithiothreitol (1 mM). The periodicity and amplitude of the Ca2+(i) oscillations produced by thimerosal and ATP differ. ATP- or thimerosal-evoked changes in Ca2+(i) were unaffected by dantrolene sodium (10 μM). The Ca2+-ATPase inhibitor thapsigargin (1μM) increased Ca2+(i) and attenuated subsequent ATP-evoked changes in Ca2+(i). We conclude that ATP stimulates an oscillatory release of Ca2+ from InsP3-sensitive stores in hG/LCs.

Keywords:adenosine triphosphate, caffeine, calcium ion, dantrolene, dithiothreitol, fura 2, inositol trisphosphate, thapsigargin, thiomersal, article, calcium cell level, calcium transport, controlled study, extracellular calcium, female, granulosa cell, human, human cell, luteal cell, microfluorometry, priority journal, spike, Adenosine Triphosphate, Calcium, Calcium-Transporting ATPases, Cells, Cultured, Central Nervous System Stimulants, Enzyme Inhibitors, Fluorometry, Granulosa Cells, Humans, Inositol 1,4,5-Trisphosphate, Luteal Cells, Muscle Relaxants, Central, Thimerosal
Subjects:C Biological Sciences > C990 Biological Sciences not elsewhere classified
Divisions:College of Science > School of Life Sciences
ID Code:14359
Deposited On:20 Jun 2014 12:03

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