Jpn. J. Pharmacol. 84 (4), 474-475 (2000)

Ca²⁺-Sensitization of Contraction in the h1 Calponin-Deficient Smooth Muscle

Ryo Yoshimoto¹, Masatoshi Hori¹, Katsuhito Takahashi^2,3,4, Shun-ichiro Taniguchi⁵, Motoya Katsuki⁶,
Hiroshi Ozaki¹ and Hideaki Karaki^1,*

¹Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8511, Japan
²Department of Medicine, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka 537-8511, Japan
³The Graduate School of Pharmaceutical Science, Osaka University, Osaka 565-0871, Japan
⁴PRESTO, Japan Science and Technology Corporation
⁵Research Center on Aging and Adaptation, Shinshu University School of Medicine, Nagano 657-0013, Japan
⁶Department of DNA Biology and Embryo Engineering, Institute for Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
*Corresponding author.ﾊﾊFax:+81-3-5841-8183
E-mail: ahkrki@mail.ecc.u-tokyo.ac.jp

Abstract: Role of h1 calponin on Ca²⁺-sensitivity of smooth muscle contraction was investigated using h1 calponin gene-deficient mice (CP-/-) and wild type mice (CP+/+). PGF_2a induced a comparable force in intact aorta of CP+/+ and CP-/-. DPB showed similar effects to PGF_2a. In membrane-permeabilized ileal smooth muscle, PDBu enhanced Ca²⁺-sensitivity of contraction comparably in CP+/+ and CP-/-. GTPg-S showed similar effects. Our results suggest that h1 calponin does not regulate Ca²⁺-sensitivity in the contractile mechanism of smooth muscle.

Keywords: Calponin, Ca²⁺-sensitization, Smooth muscle contraction