INSP(3)-INDUCED CA2-ROOT GANGLION NEURONS( RELEASE IN DORSAL)

The intracellular calcium signalling was studied on subpopulation of f reshly isolated adult mouse dorsal root ganglia (DRG) neurones with la rge somatas (30-45 mu in diameter). The cytoplasmic Ca2+ concentration ([Ca2+](i)) was measured using indo-1 based microfluorimetry. The ext racellular application of ATP (100 mu M) 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 C a2+ elevation was inhibited by intracellular perfusion of DRG neurones with 20 mu M heparin, or by cells incubation with thapsigargin or rya nodine. We conclude that mouse proprioceptive sensory neurones are end owed with Ca2+-impermeable ionotropic P-2X purinoreceptors and metabot ropic P-2Y purinoreceptors, which, by means of phospholipase C-driven inositol-trisphosphate (InsP(3)) production, trigger the InsP(3)-induc ed Ca2+ release from intracellular stores. (C) 1997 Elsevier Science I reland Ltd.