7565633

pubmed:Citation

3

Antigenic stimulation of rat basophilic leukemia cells releases Ca2+ from internal stores and increases membrane permeability to Ca2+. The delta isomer of hexachlorocyclohexane (delta-HCH) is structurally similar to myo-inositol-1,4,5-trisphosphate (IP3) and is a potent releaser of stored Ca2+ from permeabilized cells. This release of Ca2+ is not mediated by a competitive interaction with the IP3 receptor on the Ca2+ release channel on the endoplasmic reticulum. In intact cells, delta-HCH and, to a lesser extent, lindane (gamma-hexachlorocyclohexane) transiently increase the intracellular Ca2+ concentration. The return to basal concentrations is mediated by the plasma membrane Ca2+ pumps and not by resequestration of Ca2+ into intracellular stores. Treatment of cells with delta-HCH (25-100 microM), but not lindane, leads to a progressive inhibition of the antigen- and thapsigargin-stimulated Ca2+ signal. Caffeine, a modulator of the ryanodine receptor Ca2+ channel, attenuates the rise in intracellular Ca2+ induced by delta-HCH, suggesting that ryanodine receptor-like Ca2+ channels may be present in RBL cells. At 25 microM delta-HCH, a concentration that does not inhibit the antigen-stimulated Ca2+ signal, the release of [3H]serotonin from antigen-stimulated cells is enhanced as is secretion of [3H]serotonin from cells pretreated with 25-100 microM lindane. The depletion of Ca2+ from intracellular stores by delta-HCH should evoke Ca2+ entry into the cells by a capacitative mechanism; however; divalent cation permeability across the plasma membrane (Mn2+ influx) is not increased but rather is decreased by delta-HCH. An understanding of the mechanism of action of delta-HCH in releasing stored Ca2+ and blocking Ca2+ influx across the plasma membrane may provide insights into the regulation of capacitative Ca2+ entry in nonexcitable cells.

eng

IM

MEDLINE

0026-895X

Print

NLM

512-22

pubmed-meshheading:7565633-Adenosine Triphosphate, pubmed-meshheading:7565633-Animals, pubmed-meshheading:7565633-Antigens, pubmed-meshheading:7565633-Binding, Competitive, pubmed-meshheading:7565633-Caffeine, pubmed-meshheading:7565633-Calcium, pubmed-meshheading:7565633-Calcium-Transporting ATPases, pubmed-meshheading:7565633-Cell Membrane Permeability, pubmed-meshheading:7565633-Endoplasmic Reticulum, pubmed-meshheading:7565633-Enzyme Inhibitors, pubmed-meshheading:7565633-Inositol 1,4,5-Trisphosphate, pubmed-meshheading:7565633-Intracellular Fluid, pubmed-meshheading:7565633-Isomerism, pubmed-meshheading:7565633-Leukemia, Basophilic, Acute, pubmed-meshheading:7565633-Lindane, pubmed-meshheading:7565633-Manganese, pubmed-meshheading:7565633-Rats, pubmed-meshheading:7565633-Sensitivity and Specificity, pubmed-meshheading:7565633-Signal Transduction, pubmed-meshheading:7565633-Stimulation, Chemical, pubmed-meshheading:7565633-Terpenes, pubmed-meshheading:7565633-Thapsigargin, pubmed-meshheading:7565633-Tritium, pubmed-meshheading:7565633-Tumor Cells, Cultured

The delta isomer of hexachlorocyclohexane induces rapid release of the myo-inositol-1,4,5-trisphosphate-sensitive Ca2+ store and blocks capacitative Ca2+ entry in rat basophilic leukemia cells.

Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't