Effect of an increase in occlusal vertical dimension on the rate of cyclic actin-myosin interaction in guinea-pig masseter muscle

• Published in: Archives of oral biology Vol. 42; no. 7; pp. 505 - 512
• Main Authors: Kawasaki, K., Saeki, Y., Ohnuki, Y.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.1997
• Subjects: Actins - chemistry; Actins - metabolism; actomyosin kinetics; Adenosine Triphosphatases - analysis; Adenosine Triphosphatases - metabolism; Animals; ATPase activity; bite opening; Drug Interactions; Guinea Pigs; guinea-pig; in vitro motility assay; Male; Malocclusion - etiology; Malocclusion - metabolism; masseter muscle; Masseter Muscle - chemistry; Masseter Muscle - metabolism; Myosins - chemistry; Myosins - metabolism; Orthodontic Appliances; Vertical Dimension; bite opening; N-Tris (hydroxynethyl)methyl-2-amino-ethanesulphonic acid; guinea-pig; in vitro motility assay; dithiothreitol; TES; ATPase activity; masseter muscle; DTT; actomyosin kinetics
• ISSN: 0003-9969; 1879-1506
• DOI: 10.1016/S0003-9969(97)00038-1

To study the effects of increased occlusal vertical dimension on these kinetics, the actin-filament sliding velocity on masseter myosins in an in vitro motility assay and the ATPase activity of masseter myosins from normal (control [and bite-opened (5.6 mm increase in the vertical dimension for 1 week (guinea.-pigs were measured. In control myosin preparations, the average value ( mean ± SD, n = 5) for the actin-filament sliding velocity at 25°C was 4.0 ± 0.3 μm/sec. In bite-opened myosin preparations ( n = 5), it was 3.4 ± 0.3 μm/sec a significant ( p < 0.01) decrease. Myosin ATPase activity was also decreased significantly ( p < 0.01) from 1.0 ± 0.1 to 0.7 ± 0.1 μmol Pi mg per min (mean ± SD, n = 5) after the bite opening. These results strongly suggest that in guinea-pigs an increase in occlusal vertical dimension for 1 week decreases the turnover rate of actin-myosin interaction in the masseter through charges in the myosin isozyme. These changes may result in a slowing of the rate of detachment of myosin cross-bridges from actin filaments.