INTERACTION OF FLUORESCEIN DERIVATIVES WITH GLIBENCLAMIDE BINDING-SITES IN RAT-BRAIN

In rat brain, [H-3]glibenclamide binds with high affinity to sulfonylurea receptors associated with ATP-sensitive potassium (K-ATP) channels. K-ATP channels may play a modulatory role in neurotransmitter release and are involved in acute pathological events occurring in the brain. Fluorescein derivatives, which are suitable tools for the labelling of nucleotide binding sites, influence K-ATP channels and sulfonylurea receptors properties in insulinoma and cardiac cells. In this study, a negative allosteric action of fluorescein derivatives on glibenclamide binding sites has been shown in rat cortical neurons. This supports the hypothesis of interactions between nucleotide- and sulfonylurea-binding sites within the sulfonylurea receptor.