The A2-selective adenosine analog, CGS 21680, depresses locomotor activity but does not block amygdala kindled seizures in rats.

The actions of the highly selective A2 adenosine agonist, CGS 21680, in modulating kindled seizures and locomotor activity were examined. I.c.v. injections of CGS 21680 into the lateral cerebral ventricle in fully kindled rats were found to prolong the period of postictal EEG depression and reduce postictal spiking in a dose-dependent manner, while not affecting the behavioral seizure stage or afterdischarge duration. CGS 21680 injections also lead to a dose-related inhibition of locomotor activity in rats exposed to an open field apparatus compared to rats receiving control injections of saline. These observations implicate the involvement of the A2 adenosine receptor in postictal phenomena and the locomotor depressant actions of adenosine, but do not indicate a direct anticonvulsant activity following A2 activation.