Frequently Asked Questions Live Chat and Frequently Asked Questions are available for this Product. Caution Photosensitive Biochem/physiol Actions KN-93 is a selective Ca2+/calmodulin-dependent protein kinase II inhibitor, which has been implicated in the regulation of smooth muscle contractility. CaM kinase II activation was inhibited by KN-93 pretreatment (IC50 ~1 μM). KN-93 inhibited histamine-induced tonic force maintenance, whereas early force development and MLC20 phosphorylation responses during the entire time course were unaffected. Both force development and maintenance in response to KCl were inhibited by KN-93. Rapid increases in KCl-induced MLC20 phosphorylation were also inhibited by KN-93, whereas steady-state MLC20 phosphorylation responses were unaffected. In contrast, phorbol 12,13-dibutyrate (PDBu) did not activate CaM kinase II and PDBu-stimulated force development was unaffected by KN-93. Thus KN-93 appears to target a step(s) essential for force maintenance in response to physiological stimuli, suggesting a role for CaM kinase II in regulating tonic contractile responses in arterial smooth muscle. Pharmacological activation of protein kinase C bypasses the KN-93 sensitive step. |