Mechanism by which GABA, through its GABAA receptor, modulates glutamate release from rat cortical neurons in culture

In cortical neurons, the GABAA agonist, muscimol, increases: (a) basal glutamate release (with a EC50 of 99±7 mM); (b) intracellular calcium and (c) membrane potential, all of these in a dose-dependent manner. These muscimol effects were specific since they were reversed by bicuculline, a GABAA antagonist.