Inhibition of Glutamate Release by Bia 2-093 and Bia 2-024, Two Novel Derivatives of Carbamazepine, Due to Blockade of Sodium but Not Calcium Channels11Abbreviations: Aed, Antiepileptic Drug; Cbz, Carbamazepine; Oxc, Oxcarbazepine; and 4-Ap, 4-Aminopyridine.