Protein kinase C inhibitor BIM suspended TRPV1 effect on mu-opioid receptor

Abstract

The purpose of the present study was to elucidate the role of protein kinase A and C in the mechanism of capsaicin inhibition on mu-opiate receptors. H89, a protein kinase A inhibitor and BIM (bisindolylmaleimide), a protein kinase C inhibitor were used for this purpose. BIM suspended the inhibition of capsaicin in endomorphin-1 competition binding. The addition of BIM alone had no effect itself on this reaction. H89 however, exerted a strong inhibitory effect on the endomorphin-1 binding. We can conclude that protein kinase C certainly plays a role in the inhibition of capsaicin. The role of protein kinase A in this reaction could not be established, owing to the blocking effect of H89 on the mu-opioid receptors.