All animals have the ability to move. In most animals, striated muscles move the body and smooth muscles the internal organs. In both muscles, contraction results from interaction between myosin and actin filaments. Based on vertebrate studies, smooth and striated muscles are thought to have different protein components and filament structures. We have studied muscle ultrastructure in the paras...

Smooth muscle contraction regulated by myosin light chain phosphorylation is also regulated at the thin-filament level. Tropomyosin, a thin-filament regulatory protein, regulates contraction by modulating actin-myosin interactions. Present investigation shows that acetylcholine induces PKC-mediated and calcium-dependent phosphorylation of tropomyosin in colonic smooth muscle cells. Our data als...

Calponin and caldesmon are two thin filament-binding proteins found in smooth muscle that have both been attributed a role in modulating the interaction of actin and myosin. Using high-resolution dual-label immunocytochemistry we have determined the distribution of calponin relative to the contractile and cytoskeletal compartments of the smooth muscle cell. We show, using chicken gizzard smooth...

The basis of tonic vs. phasic contractile phenotypes of visceral smooth muscles is poorly understood. We used gel electrophoresis and quantitative scanning densitometry to measure the content and isoform composition of contractile proteins in opossum lower esophageal sphincter (LES), to represent tonic muscle, and circular muscle of the esophageal body (EB), to represent phasic smooth muscle. T...

BACKGROUND Leishmaniasis is caused by protozoa of Leishmania spp. genus. It is transmitted by the bite of the sand fly insect. It is believed that 12 million people are infected with this disease and that its annual incidence is 2 million; this number is increasing. OBJECTIVES The present study aimed to evaluate the expression of myofibroblasts through alpha smooth muscle actin labeling, and ...

BACKGROUND AND PURPOSE We examined the associations among the vascular beta-amyloid levels, smooth muscle actin, wall thickness, and lumen diameter to achieve greater understanding of the arteriolar changes that accompany Alzheimer disease (AD). METHODS Post-mortem pathology brain specimens from 76 patients with AD and 19 non-AD age control subjects were studied. We analyzed arterioles of the...

Arterial proteoglycans have been implicated in several important physiological processes ranging from lipid metabolism to regulation of smooth muscle cell growth. Vascular smooth muscle (VSM) cells are the major producers of proteoglycans in the medial layer of blood vessels. To study functional consequences of alterations in VSM proteoglycan metabolism we used 4-methylumbelliferyl-beta-D-xylos...