A role for purinergic receptors at the inner hair cell-afferent synapse?

Previously published evidence is reviewed for a functional role of ATP and its receptors at the chemical synapse between the mammalian inner hair cell and the primary afferent dendrites of the VIIIth nerve. New findings are also presented, both from gross cochlear potentials and single neurone recordings during intracochlear perfusion of ATP-receptor antagonists and agonists. Both the previous and present results are consistent with the notion that endogenous ATP may act to regulate the excitability of the primary afferent dendrite, possibly acting on P2X2 receptors.