Differential osmotic behavior of water components in living skeletal muscle resolved by 1H-NMR

¹ Department of Physiology,Jikei University School of Medicine

^* To whom correspondence should be addressed. E-mail: masako{at}jikei.ac.jp.

Submitted on January 17, 2005
Revised on March 18, 2005
Accepted on 29 April 2005

	Abstract

Using frog sartorius muscle, we observed transverse relaxation process of 1H-NMR signals from myowater. The process could be well described by four characteristic exponentials; the extremely slow exponential of relaxation time constant (T2) > 0.4 s, the slow one of T2 around 0.15 s, the intermediate one of 0.03 s < T2 < 0.06 s and the rapid one of T2 < 0.03 s. Addition of isotonic extracellular solution affected only the extremely slow exponential linearly increasing its amplitude and gradually increasing its T2 toward that of the bulk solution (1.7 s). Therefore, this exponential should represent extracellular surplus solution independently of the other exponentials. At two thirds to three times the isotonicity, the amplitude of the intermediate exponential showed normal osmotic behavior in parallel with the volume change of the myofilament lattice measured with X-ray diffraction. At the same tonicity range, the amplitude of the rapid exponential showed converse osmotic behavior. Lower tonicities increased the amplitude of only the slow exponential. Studied tonicities did not affect the T2 values. The distinct osmotic behavior indicated that each characteristic exponential could be viewed as a distinct water group. In addition, the converse osmotic behavior suggested that the rapid exponential would not be a static water layer on the macromolecule surface.

Key Words: nuclear magnetic resonanse, osmolarity, proton, transverse relaxation

This article has been cited by other articles:

				M. Kimura and S. Takemori CH2-Units on (Poly-)ethylene Glycol Radially Dehydrate Cytoplasm of Resting Skinned Skeletal Muscle J. Biochem., June 1, 2008; 143(6): 841 - 847. [Abstract] [Full Text] [PDF]

				M. Kimura and S. Takemori CH2-Units on (Poly-)ethylene Glycol Radially Dehydrate Cytoplasm of Resting Skinned Skeletal Muscle J. Biochem., January 1, 2008; 143(1): 123 - 129. [Abstract] [Full Text] [PDF]

				S. Takemori, M. Yamaguchi, and M. Kimura Skinning Effects on Skeletal Muscle Myowater Probed by T2 Relaxation of 1H-NMR Biophys. J., May 15, 2007; 92(10): 3610 - 3614. [Abstract] [Full Text] [PDF]