Cell-to-cell spread of calcium signals mediated by ATP receptors in mast cells

Abstract

RAT basophilic leukaemia cells, like mast cells from which they are derived, have surface Feɛ receptors that trigger secretion of inflammatory mediators when crosslinked. Both GIF-binding proteins and a rise in cytosolic calcium concentration ([Ca²⁺]_i) are implicated in the secretory mechanism^1–5. Here we use a video-imaging technique to report that transient rises in [Ca²⁺]_i initiated in an individual cell can spread from cell to cell in a wave-like pattern by means of a secreted intermediate, in the absence of gap-junctional communication. We find that the leukaemia cells, peritoneal mast cells and mucosal mast cells have cell-surface P₂-type purinergic receptors that can trigger similar [Ca²⁺]_i transients. We provide evidence that ATP is rapidly released, and that it can amplify [Ca²⁺]_i signals and initial secretory responses during antigen-stimulation of rat basophilic leukaemia cells.