スキンド盲腸紐平滑筋標本のX線回折

抄録

Mechanical response and structural changes of contractile filaments in skinned smooth muscles from guinea pig taenia caeci were simultaneously measured using X-ray diffraction technique. Cell membrane of the intact taenia was chemically permeabilized with β-escin. The diffraction pattern showed the 14.4-nm myosin reflection, the 5.9-nm actin layer-line and the equatorial peak at 1/11.4 nm⁻¹ originated from packed array of thin filaments as previously observed in intact preparatios from taenia caeci (Watanabe et al., 1993). During activation with Ca²⁺, the skinned preparations contracted and the intensity of 14.4-nm reflection significantly increased. When the contraction was inhibited by application of blebbistatin, a potent inhibitor of myosin II ATPase, the 14.4-nm reflection was significantly decreased. Since blebbistatin is known to disrupt myosin filament organization, X-ray diffraction may be a useful tool to evaluate dynamics of myosin filament organization in smooth muscle cells. [J Physiol Sci. 2008;58 Suppl:S65]