Purinergic Signaling in Terminal Schwann Cells Associated with Sensory Endings
Laboratory of Histology and Cytology, Hokkaido University Graduate School of Medicine
Abstract: The terminal Schwann cells that represent glial elements in cutaneous mechanoreceptors are characterized by their processes that branch into lamellar coverings of different axon terminals. By experiments with isolated lanceolate endings―motion detectors of rat vibrissae―we have previously shown these cells to respond to application of the intercellular signal substance ATP with an elevation of the cytoplasmic Ca2+ concentration through activation of their purinceptors P2Y2. This report presents our recent confocal image analyses demonstrating that the Schwann lamellae can detect ATP release induced by local mechanical stimuli with their own purinoceptors to generate a Ca signal confined within the length of the processes (1), and that endogenous ecto-ATPase regulates the range of intracellular signal propagation (2), and that caveola-dependent localization of Ca signaling molecules to the Schwann lamellae is essential for the subcellular compartmentalization in the purinergic cell signals. Possible Schwann cell effects induced by the compartmentalized signals on the accompanying mechanoreceptor axons in the intact organ will be discussed.
Key words: mechanoreceptors, lanceolate endings, ATP, glia, confocal microscope