Adenosine involvement in postictal events in amygdala-kindled rats.

The actions of adenosine in modulating amygdala kindling were examined using the stable adenosine analog 5'-N'-ethylcarboxamidoadenosine (NECA) and caffeine, an adenosine antagonist. Systemically administered NECA was found to significantly reduce the rate of postictal spiking and to significantly increase the duration of postictal EEG depression in amygdala kindled rats. In contrast, systemically administered caffeine significantly increased kindled seizure duration and reduced the duration of postictal EEG depression. Systemic administration of the methylxanthine derivative, 8-sulfophenyl theophylline (8-PST), failed to block the effects of NECA on kindling. Since systemically administered 8-PST blocks peripheral adenosine receptors, but has only limited CNS activity, the effects of NECA appear to be centrally mediated. These observations further demonstrate a role for adenosine in postictal phenomena and support the hypothesis that a release of endogenous adenosine contributes to the termination of ongoing seizure activity.