EPAC Inhibition of SUR1 Receptor Increases Glutamate Release and Seizure Vulnerability.

EPAC (Exchange Proteins Activated by cAMP) regulates glutamate transmitter release in the central neurons, but a role underlying this regulation has yet to be identified. Here we show that EPAC binds directly to the intracellular loop of an ATP-sensitive potassium (KATP) channel type-1 sulfonylurea receptor (SUR1) receptor consisting of amino acids 859 - 881 (SUR1 859-881). Ablation of EPAC or expression of SUR1 859-881, which intercepts EPAC-SUR1 binding, increases the open probability of KATP channels consisting of the Kir6.1 subunit and SUR1. Opening of KATP channels inhibits glutamate release and reduces seizure vulnerability in adult mice. Therefore, EPAC inter-action with SUR1 controls seizure susceptibility and possibly acts via regulation of glutamate release. [ABSTRACT FROM AUTHOR]