Biomaterial Database

Effects of modulators of myosin phosphorylation on isometric force and shortening velocity in skinned smooth muscle. 1990

J D Strauss, and P T Szymanski, and J Di Salvo, and R J Paul

Department of Physiology and Biophysics, College of Medicine, University of Cincinnati, OH 45267-0576.

Using different modulators of myosin phosphorylation, we were able to demonstrate several different relations between Fo and Vus. The data from our studies using phosphatase indicate that force and velocity may be similarly influenced by high concentration of this enzyme which is known to modulate phosphorylation. H8, however, generated a relation in which Vus is sensitive to this modulator of myosin phosphorylation and Po is relatively insensitive except at high concentrations of H8. Whether these relations are attributable to changes in phosphorylation is still questionable and under investigation. Because H8 is competitive with respect to ATP and the effect is calcium-insensitive, it may instead have a direct effect on the actin-myosin interaction. ML9, a compound which has been reported to have effects upon MLCK through a mechanism similar to that of H8, yields a relation different than H8 but similar to the phosphatase, that is, both force and velocity decreased in a nearly parallel manner. Using these modulators, we have found that the relation between Po and Vus is not unique, reinforcing the hypothesis that crossbridge number and cycle rate may be independently modulated in smooth muscle. (Paul, 1989).

UI	MeSH Term	Description	Entries
D007537	Isometric Contraction	Muscular contractions characterized by increase in tension without change in length.	Contraction, Isometric,Contractions, Isometric,Isometric Contractions
D007546	Isoquinolines	A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D009218	Myosins	A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.	Myosin ATPase,ATPase, Actin-Activated,ATPase, Actomyosin,ATPase, Myosin,Actin-Activated ATPase,Actomyosin ATPase,Actomyosin Adenosinetriphosphatase,Adenosine Triphosphatase, Myosin,Adenosinetriphosphatase, Actomyosin,Adenosinetriphosphatase, Myosin,Myosin,Myosin Adenosinetriphosphatase,ATPase, Actin Activated,Actin Activated ATPase,Myosin Adenosine Triphosphatase
D010744	Phosphoric Monoester Hydrolases	A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate.	Phosphatase,Phosphatases,Phosphohydrolase,Phosphohydrolases,Phosphomonoesterase,Phosphomonoesterases,Phosphoric Monoester Hydrolase,Hydrolase, Phosphoric Monoester,Hydrolases, Phosphoric Monoester,Monoester Hydrolase, Phosphoric
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001381	Azepines	Seven membered heterocyclic rings containing a NITROGEN atom.	Hexamethyleneimines