The intracellular calcium signaling was studied on subpopulation of freshly isolated adult mouse dorsal root ganglia (DRG) neurones with large somatas (30-45 μ in diameter). The cytoplasmic Ca2+ concentration ([Ca2+](i)) was measured using indo-1 based microfluorimetry. The extracellular application of ATP (100 μM) triggered both inward current and [Ca2+](i) elevation. Removal of extracellular Ca2+ had no effect on both ATP-induced current and [Ca2+](i) transient. The ATP-induced Ca2+ elevation was inhibited by intracellular perfusion of DRG neurones with 20 μM heparin, or by cells incubation with thapsigargin or ryanodine. We conclude that mouse proprioceptive sensory neurones are endowed with Ca2+ - impermeable ionotropic P(2X) purinoreceptors and metabotropic P(2Y) purinoreceptors, which, by means of phospholipase C-drive inositol- trisphosphate (InsP3) production, trigger the InsP3-induced Ca2+ release from intracellular stores.
- Ca release
- Cytoplasmic calcium
- Inositol-trisphosphate (InsP)
- Sensory neurones
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