ha-1100 and Coronary-Vasospasm

We have recently demonstrated that protein kinase C (PKC) and Rho-kinase play important roles in coronary vasospasm in a porcine model. However, it remains to be examined whether there is an interaction between the two molecules to cause the spasm.. A segment of left porcine coronary artery was chronically treated with IL-1beta-bound microbeads in vivo. Two weeks after the operation, phorbol ester caused coronary spasm in vivo and coronary hypercontractions in vitro at the IL-1beta-treated segment; both were significantly inhibited by hydroxyfasudil, a specific Rho-kinase inhibitor. Guanosine 5'-[gamma-thio]triphosphate (GTPgammaS), which activates Rho with a resultant activation of Rho-kinase, enhanced Ca2+ sensitization of permeabilized vascular smooth muscle cells, which were resistant to the blockade of PKC by calphostin C. The GTPgammaS-induced Ca2+ sensitization was greater in the spastic segment than in the control segment. Western blot analysis revealed that only PKCdelta isoform was activated during the hypercontraction.. These results demonstrate that PKC and Rho-kinase coexist on the same intracellular signaling pathway, with PKC located upstream on Rho-kinase, and that among the PKC isoforms, only PKCdelta may be involved. Thus, the strategy to inhibit Rho-kinase rather than PKC may be a more specific and useful treatment for coronary spasm.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Blotting, Western; Calcium; Capillary Permeability; Coronary Vasospasm; Coronary Vessels; Disease Models, Animal; Enzyme Activation; Enzyme Inhibitors; Guanosine 5'-O-(3-Thiotriphosphate); In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Male; Monomeric GTP-Binding Proteins; Muscle Contraction; Muscle, Smooth, Vascular; Phorbol 12,13-Dibutyrate; Protein Kinase C; Protein Serine-Threonine Kinases; Protein Transport; rho-Associated Kinases; Swine