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Understanding of the pathogenesis of cerebral vasospasm requires basic study of the contraction mechanism of cerebral arteries. In this study, the morphological and biochemical properties of actomyosin from bovine cerebral arteries were examined. Arrays of thick and thin filaments were clearly seen on electron micrographs of a cross section of a muscle strip stretched to 1.5 times its normal length in Krebs-Ringer solution. The diameters of the thick and thin filaments were 110.0 +/- 19.9 A and 51.0 +/- 8.0 A, respectively. The average ratio of thick to thin filaments was about 1:15 to 1:16. The gel pattern of Ca2+-sensitive actomyosin extracted from bovine cerebral arteries revealed the presence of myosin, actin, and tropomyosin, but not skeletal troponin. The Mg-ATPase activity of actomyosin was greatly enhanced in the presence of Ca2+. Rapid superprecipitation occurred after the clearing phase, when 1 mM Mg-ATP was added to a suspension of actomyosin with 10(-5) M Ca2+. This superprecipitation did not occur with a lower Ca2+ concentration of 10(-8) M. Intracellular free Ca2+ appears to play a crucial role in the regulation of contraction and relaxation of cerebral arterial smooth muscle.
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
January 1978,
Neurologia medico-chirurgica,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
October 1976,
Biochimica et biophysica acta,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
December 1997,
Biology of reproduction,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
November 1998,
The American journal of physiology,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
May 1965,
Nature,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
January 1986,
The Japanese journal of physiology,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
January 1983,
Progress in biophysics and molecular biology,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
January 1995,
Advances in second messenger and phosphoprotein research,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
July 1962,
Physiological reviews. Supplement,
T Takagi, and
H Fukuoka, and
E C Tan, and
N Itoh, and
K Hotta
January 1982,
Society of General Physiologists series,
