FAST PURINERGIC TRANSMISSION IN THE CENTRAL-NERVOUS-SYSTEM

Fast synaptic transmission. mediated by P-2x ATP receptors is a recent discovery in the central nervous system and new information on the di stribution of P-2x binding sites and mRNA for P-2x receptor subunits i n the brain suggests that transmission mediated by ATP may be widespre ad. P-2x ATP receptors have many functional similarities to other rece ptors mediating fast excitatory synaptic transmission and some signifi cant differences. ATP release is calcium-dependent and vesicular in na ture. Individual synaptic currents are small in size (around 10 pA at -70 mV), have a fast rise-time and decay with a time-course (decay tau = 18 ms at -70 mV) intermediate between that of AMPA receptor-mediate d synaptic currents and NMDA receptor-mediated synaptic currents. It i s likely that P-2x ATP receptor channels are permeable to calcium sugg esting by analogy with glutamatergic transmission that purinergic tran smission will participate in the regulation of calcium-dependent proce sses in neurones. (C) 1996 Academic Press Ltd