Intranigral gamma-vinyl-GABA (GVG) suppresses electroshock seizures (ES). This anticonvulsant action was blocked by systemic treatment with the alpha 2-antagonist idazoxan. Consequently, we tested the idea that intranigral GABA mimetics suppress ES by increasing noradrenergic (NE) neuronal activity. Contrary to our hypothesis, GVG decreased NE turnover. This result indicates that while the seizure-suppressant effect of intranigral GVG requires alpha 2-mediated NE neurotransmission, the mechanism of this anticonvulsant action is not by increasing NE neuronal activity.