All-or-none cell shortening of isolated single smooth muscle cells to acetylcholine and Ca2+ sensitization.

Smooth muscle cells were isolated from estrogenized rat myometrium by collagenase digestion. Electron microscopic examination and measurement of cell lengths by image-splitting micrometry were carried out after fixation with acrolein. Mean lengths of cells before and after isolation were 81.7 and 66.9 μm, respectively. Responses of cells were compared with contractions of isolated strips recorded isometrically. Effects of carbachol and KCl were examined in 2 mM Ca, 2 mM Ca + 4 mM EGTA, and 2 mM Ca + 10−8 M nitrendipine solution. Carbachol and KCl produced concentration-dependent shortening of isolated cells maximal at 30 s after addition. The concentrations of carbachol required to produce shortenings were about 100-fold less than those required to produce isometric contractions; but no major difference was observed in the concentration dependence of cell shortening and isometric contraction produced by potassium-induced depolarization. In 2 mM Ca solution, there was a phasic response, followed by a tonic response such that more than 50% of maximum cell shortening was maintained for 10 min. However, in 2 mM Ca + 4 mM EGTA or 10−8 M nitrendipine, the tonic contraction was abolished and cells rapidly relaxed after 30 s. If carbachol was added to cells after varying times in the EGTA-containing solution, the ability to initiate a contraction declined exponentially with a half-time of 160 s. Effects of depolarization by KCl were examined in 2 mM Ca plus nitrendipine and 2 mM Ca + 4 mM EGTA solution. Shortening occurred in 2 mM Ca solution by depolarization but not if nitrendipine was added. Though shortening was not observed in 2 mM Ca + 4 mM EGTA solution by KCl, subsequent addition of carbachol induced shortening. These results suggested that there was an intracellular Ca store site from which Ca was released by carbachol and which was not affected by depolarization in the absence of external Ca. No evidence was obtained that the contraction persists in Ca2+-free medium in isolated cells, which is in agreement with previous findings in small muscle strips in which only a similar transient response was obtained.

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119 Effects of inhibition of tubulin polymerization and depolymerization on tensile properties and cell shortening dunng detachment of cultured aortic smooth muscle cells

The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME ◽

10.1299/jsmebio.2005.18.45 ◽

2006 ◽

Vol 2005.18 (0) ◽

pp. 45-46

Author(s):

Kazuaki NAGAYAMA ◽

Akira TSUGAWA ◽

Takeo MATSUMOTO

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Tensile Properties ◽

Muscle Cells ◽

Tubulin Polymerization ◽

Aortic Smooth Muscle Cells ◽

Aortic Smooth Muscle ◽

Cell Shortening

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Ca2+ and MgATP2- dependence of shortening in skinned single smooth muscle cells

AJP Cell Physiology ◽

10.1152/ajpcell.1987.252.4.c418 ◽

1987 ◽

Vol 252 (4) ◽

pp. C418-C427 ◽

Cited By ~ 4

Author(s):

D. M. Warshaw ◽

W. J. McBride ◽

M. S. Hubbard

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Single Cells ◽

Muscle Cells ◽

Calcium Sensitivity ◽

Measuring System ◽

Free Calcium ◽

Computer Assisted ◽

Cell Shortening ◽

Toad Bufo

Most studies of skinned smooth muscle have been performed in whole tissue preparations. In this study, we report the development of a chemically skinned single smooth muscle cell preparation from the toad, Bufo marinus, stomach. Isolated smooth muscle cells were skinned using saponin. The effect of various ionic environments (i.e., changing free Ca2+ and MgATP2-) on skinned cell contractile response was assessed by measuring cell lengths from populations of cells using a computer-assisted length-measuring system. Comparison of cell length histograms were used to determine the extent of cell shortening in response to a given ionic perturbation. Once skinned, the single cells shortened with a sensitivity to free calcium (ED50 = 1.5 microM Ca2+) that was three orders of magnitude lower than potassium depolarized cells (ED50 = 1.5 mM Ca2+). In addition to the calcium sensitivity, the effect of free MgATP2- on the extent of cell shortening was investigated. The extent of cell shortening was dependent on free MgATP2- with the maximum shortening response occurring at MgATP2- greater than 1 mM.

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Immunogold localization of HMB-45 antigen in pulmonary lymphangiomyomatosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141366 ◽

1995 ◽

Vol 53 ◽

pp. 998-999

Author(s):

J.M. Minda ◽

E. Dessy ◽

G. G. Pietra

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Room Temperature ◽

Osmium Tetroxide ◽

Muscle Cells ◽

Ultrastructural Localization ◽

Reproductive Age ◽

Thin Sections ◽

Smooth Muscle Proliferation ◽

Hmb 45

Pulmonary lymphangiomyomatosis (PLAM) is a rare disease occurring exclusively in women of reproductive age. It involves the lungs, lymph nodes and lymphatic ducts. In the lungs, it is characterized by the proliferation of smooth muscle cells around lymphatics in the bronchovascular bundles, lobular septa and pleura The nature of smooth muscle proliferation in PLAM is still unclear. Recently, reactivity of the smooth muscle cells for HMB-45, a melanoma-related antigen has been reported by immunohistochemistry. The purpose of this study was the ultrastructural localization of HMB-45 immunoreactivity in these cells using gold-labeled antibodies.Lung tissue from three cases of PLAM, referred to our Institution for lung transplantation, was embedded in either Poly/Bed 812 post-fixed in 1% osmium tetroxide, or in LR White, without osmication. For the immunogold technique, thin sections were placed on Nickel grids and incubated with affinity purified, monoclonal anti-melanoma antibody HMB-45 (1:1) (Enzo Diag. Co) overnight at 4°C. After extensive washing with PBS, grids were treated with Goat-anti-mouse-IgG-Gold (5nm) (1:10) (Amersham Life Sci) for 1 hour, at room temperature.

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