GSK269962A (GSK269962A HCl) is a selective ROCK(Rho-associated protein kinase) inhibitor with IC50 values of 1.6 and 4 nM for ROCK1 and ROCK2, respectively.

GSK269962A completely abolished the actin stress fiber formation induced by angiotensin II in human smooth muscles. Such suppressive effect on actin fiber formation was observed beginning at around 1 μM GSK269962A. GSK269962A induced vasorelaxation in preconstricted rat aorta(tissue baths) with an IC50 of 35 nM. the relaxation induced by GSK269962A is reversible. GSK269962A suppressed IL-6 mRNA transcription and reduced LPS-induced IL-6 and TNF-α protein production in macrophages

Oral administration of GSK269962A produced a profound dose-dependent reduction of systemic blood pressure in spontaneously hypertensive rats. The reduction of blood pressure was acute and substantial. The maximal effect on blood pressure was observed approximately 2 h after oral gavages. The reduction of blood pressure was accompanied by an acute, dose-dependent increase in heart rate, presumably due to the activation of baroreflex mechanism. ROCK inhibition with the use of GSK 269962 in the 10 mg/kg dose, in turn, triggered an increase in VV(voided volume), PVR(post-void residual), VT(volume threshold), VE(voiding efficiency), ICI(intercontraction interval), BC(bladder compliance), and VTNVC(volume threshold to elicit NVC).

The enzyme activity and kinetics of the purified ROCK1(3-543) are determined using scintillation proximity assay. In this assay, purified ROCK1 is incubated with peptide substrate (Biotin-Ahx-AKRRLSSLRA-CONH2), and 33ATP and the subsequent incorporation of 33P into the peptide is quantified by streptavidin bead capture. For IC50 determination, test compounds are dissolved at 10 mM in 100% DMSO, with subsequent serial dilution in 100% DMSO. Compounds are typically assayed over an 11-point dilution range with a concentration in the assay of 10 μM to 0.2 nM in 3-fold dilutions. For dose-response curves, data are normalized and expressed as percentage inhibition using the formula 100×[(U-C1)/(C2-C1)], where U is the unknown value, C1 is the average of the high signal (0%) control wells, and C2 is the average of the low signal (100%) control wells. Curve fitting is performed The results for each compound are recorded as pIC50 values[1].

Human primary smooth muscle cells were serum-starved(cells were grown on coverslips, and at approximately 50% confluence, they were serum-starved overnight) and stimulated with AngII (100 nM) for 2 h. ROCK inhibitors (3 μM for SB-772077-B or GSK269962A) were added 30 min before AngII stimulation, and cells were fixed and stained with rhodamine phalloidin. Confocal images of actin stain were obtained.(Only for Reference)