The H series isoquinolinesulfonamide protein kinase inhibitors are widely used to block signaling pathways in order to elucidate mechanisms of cellular regulation and signal transduction. H-9 (hydrochloride), an isoquinolinesulfonamide protein kinase inhibitor, is a competitive inhibitor of PKC, PKG, and PKA with Ki values of 18, 0.87, and 1.9 μM, respectively. H-9 (hydrochloride) has been used to reduce the cAMP-mediated excitatory response to serotonin in C. elegans enteric neurons and to inhibit PKA-mediated phosphorylation in a rat seizure model.
