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Abstract #23358 Published in IGR 11-1
Rho-kinase, but not protein kinase C, is involved in generation of the spontaneous tone in the resting phase of the isolated pig iris sphincter muscle
Okano M; Uchikawa Y; Tanaka N; Mutoh J; Ohkura M; Hisa H; Yamamoto RCurrent Eye Research 2009; 34: 177-183
PURPOSE: The purpose of the present study was to clarify the role of Rho-kinase and/or protein kinase C in the resting tension of the isolated pig iris sphincter muscle. MATERIALS AND METHODS: The motor activity of the isolated pig iris sphincter muscle was measured isometrically. RESULTS: EGTA, a chelator of extracellular Ca2+, significantly reduced the resting tension. Y27632, a Rho-kinase inhibitor, significantly reduced the resting tension in a concentration-dependent manner. The resting tension diminished by Y27632 was significantly recovered by the addition of calyculin A, a myosin light chain phosphatase (MLCP) inhibitor, in a concentration-dependent manner. GF109203X, a protein kinase C inhibitor, had no effect on the resting tension. CONCLUSION: These results suggest that, in the isolated pig iris sphincter muscle, Rho-kinase plays an important role in the generation of spontaneous tone in the resting phase via the inhibition of MLCP activity.
Dr. M. Okano, Department of Orthoptics and Visual Sciences, School of Health Sciences, Kyushu University of Health and Welfare, Nobeoka, Miyazaki, Japan
Classification:
3.8 Pharmacology (Part of: 3 Laboratory methods)
2.8 Iris (Part of: 2 Anatomical structures in glaucoma)
11.14 Investigational drugs; pharmacological experiments (Part of: 11 Medical treatment)