Alterations in glutamine synthetase activity by FeCl2-induced focal and kindled amygdaloid seizures.

The purpose of this study was to determine the effects of two experimental models of chronic epilepsy in rats on the activity of the astroglial enzyme glutamine synthetase. FeCl2-induced cortical lesions that increased the sensitivity to pentylenetetrazol-induced generalized seizures also significantly increased glutamine synthetase activity in the homotopic site of the contralateral cortex. A decrease in cortical glutamine synthetase was found in the cortex ipsilateral to the stimulated amygdala in electrically kindled animals. These findings provide evidence that increased glutamine synthetase activity is associated with developing, submaximal seizures and that decreased activity is characteristic of mature, chronic seizure states such as that associated with kindled amygdala seizures.