A functional AMPA receptor-calcium channel complex in the postsynaptic membrane.

Ca(2+) channels play critical roles in the regulation of synaptic activity. In contrast to the well established function of voltage-activated Ca(2+) channels in the presynaptic membrane for neurotransmitter release, some studies are just beginning to elucidate the functions of the Ca(2+) channels in the postsynaptic membrane. In this study, we demonstrated the functional association of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors with the neuronal Ca(2+) channels. A series of biochemical studies showed the specific association of Ca(v)2.1 (alpha(1A)-class) and Ca(v)2.2 (alpha(1B)-class) with AMPA receptors in the postsynaptic membrane. Our electrophysiological and Ca(2+) imaging analyses of recombinant Ca(v)2.1 and AMPA receptors also showed functional coupling of the two channels. Considering the critical roles of postsynaptic intracellular concentration of Ca(2+) ([Ca(2+)](i)) increase and AMPA receptor trafficking for long-term potentiation (LTP) and long-term depression (LTD), the functional association of Ca(2+) channels with the AMPA receptors may provide new insights into the mechanism of synaptic plasticity.