Effect of intra -perirhinal injection of 2-chloroadenosine on amygdaloid kindled seizures in rats

Introduction . Adeno sine is a neu romodulato r wh ich has ant ico nvulsa nt effects in different labor atory models of epi lepsy includ ing kindling, but the precis e site (S) of its act ion in the brain has not been recognized . In this study, possibleantico nvulsant effects of 2-chloroadenosine injected Locally into the perirhinal cortex of amygdala kindled rats was investigated. Materials and Methods. Animals were kindled by daily electrical stimu latio n. Full amygdale rast were microi nfused ( l,ul/ 4mi n) wit h 2-chlor oad enosine ( 2-CLA 5, 10, 15, 25 and 100nM), caffei ne (50 and 100,um) or artificia l cerebro spi na l fluid a pplied th rough a guide cannula located in the perirhinal cortex and were stimulated at 10, 30 and 120 min post drug injection. Results. At the doses employed, 2-CLA sig nificantly reduced after discharge duration and stage 5 seizure duration. The latency to stage 4 seizure was increased only at the highest dose of 2-CLA (100 nM), while even at this dose no significant change in seizure stage could be seen. The maximum effect of 2-CLA was obtained 30 min after microinjection of the drug. Pretreatment (i nt ra pe rir hinal) of anima ls with the nonselective adenosine anta go nist , caffeine (50 ,urn 1 ,ul), blocked the anticonvulsan t activity of 2-CLA. Conclusion. These results suggest that adenosine receptors located in the perirhinal cortex may play an important role in the suppression of se izure activity elicited from the amygdala.