Endothelin-1 increases isoprenaline-enhanced cyclic AMP levels in cerebralcortex

We examined the effect of ET-1 on cyclic AMP levels in rat cerebral cortex. The peptide caused a concentration-dependent increase of [H-3]cyclic AMP a ccumulation after 10 min of treatment. This effect was due to adenosine acc umulation since it was inhibited by the treatment with adenosine deaminase. ET-1, apart from being able to increase cyclic AMP, also potentiated the c yclic AMP generated by isoprenaline in the presence of adenosine deaminase. Experiments performed in the presence of BQ-123 or BQ-788, specific ETA or ETB receptor antagonists respectively indicated that ETB was the receptor involved. This effect was dependent on extracellular and intracellular calc ium concentration. These findings suggest that ET-1 plays a modulatory role in cyclic AMP generation systems in cerebral cortex. (C) 2000 Elsevier Sci ence B.V. All rights reserved.