Ecto-ATPase activity in cerebellum: implication to the function of synaptic transmission

The involvement of ATP in synaptic transmission was examined in synapses on granule cells of the rat cerebellum using ecto-ATPase activity. Reaction p roduct was found in a majority but not all synapses between axodendritic, a xoaxonic, and dendrodendritic appositions of granule cells and was associat ed with extracellular surface of both pre- and postsynaptic membranes. Spec ificity of the detection was justified by using diethyl pyrocarbonate, spec ific inhibitor of ecto-ATPase activity. These observations provide direct m orphological evidence in support of the view that ATP participates in synap tic transmission and indicate functional heterogeneity of synapses in cereb ellum. (C) 1999 Elsevier Science B.V. All rights reserved.