scholarly journals Induction of spreading during fibroblast movement.

1979 ◽  
Vol 81 (3) ◽  
pp. 684-691 ◽  
Author(s):  
W T Chen
Keyword(s):  
Leading Edge ◽  
Fold Increase ◽  
Embryonic Chick ◽  
Trailing Edge ◽  
Area Increase ◽  
Spread Area ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
Highly Correlated ◽  
The Relationship

This paper describes the phenomenon of retraction-induced spreading of embryonic chick heart fibroblasts moving in culture. Measurable criteria of cell spreading (increase in area of the spreading lamella, and total spread area of the cell) are found to change predictably with retraction of a portion of the cell margin. Ruffling activity was found to increase. The leading lamella of a spread fibroblast ordinarily advances slowly, with an average area increase of approximately 21 mu2m/min. A 10- to 30-fold increase in spreading occurs within 8 s after onset of retraction at the trailing edge and then decreases slightly so that by 1 min the increase in spreading is five to tenfold. During this period, there is a linear relationship between area increase at the leading edge and area decrease at the trailing edge. During the next 10--15 min, spreading gradually decreases to normal. Although the relationship between area spreading and area retracting of fibroblasts at different phases of movement is not significantly linear, it is highly correlated (Table II). These results suggest that the rate of fibroblast spreading may be inversely related to the degree of spreading of the cell as a whole.

Surface changes during retraction-induced spreading of fibroblasts

1981 ◽  
Vol 49 (1) ◽  
pp. 1-13 ◽  
Author(s):  
W.T. Chen
Keyword(s):  
Surface Membrane ◽  
Leading Edge ◽  
Time Lapse ◽  
Adjacent Cell ◽  
Embryonic Chick ◽  
Abrupt Increase ◽  
Trailing Edge ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
Surface Changes

Retraction of the trailing edge of an embryonic chick heart fibroblast results in an abrupt increase in protrusive activity at the leading edge of the cell. This increase was studied with time-lapse cinemicrography and scanning electron microscopy. Increased spreading following retraction results primarily from an increase in the duration of the extension phase of lamellipodial spreading. Much ruffling accompanies this increased spreading, particularly during its earliest phase. Upon retraction of the trailing edge, folds appear on the surface of the retracted tail and adjacent cell body and, soon after, microvilli-like structures appear as well. Once the moving cell has fully respread, however, the upper surface is once again smooth and free of folds and microvilli. Artificial detachment of a spreading lamella with a microneedle, and its consequent retraction, also causes increased protrusive activity of the remaining lamellae of the cell. These results are consistent with the hypothesis that retraction of one part of the cell makes surface membrane and cytoplasm available for forming protrusions elsewhere.

scholarly journals Co-culture of embryonic chick heart cells and ciliary ganglia induces parasympathetic responsiveness in embryonic chick heart cells

1993 ◽  
Vol 292 (2) ◽  
pp. 395-399 ◽  
Author(s):  
J V Barnett ◽  
M Taniuchi ◽  
M B Yang ◽  
J B Galper
Keyword(s):  
G Proteins ◽  
Fold Increase ◽  
Heart Cell ◽  
Heart Cells ◽  
Embryonic Chick ◽  
In Ovo ◽  
Chronotropic Response ◽  
Muscarinic Stimulation ◽  
Chick Heart ◽  
Embryonic Chick Heart

We have developed a system for the co-culture of embryonic chick heart cells obtained from embryos at 3.5 days in ovo with ciliary ganglia from chick embryos at 7 days in vivo. After 3 days of co-culture, removal of the ciliary ganglia resulted in complete degeneration of axons within 6-8 h, leaving the post-innervated heart cell culture devoid of neurons. Embryonic chick heart cells at 3.5 days in ovo are unresponsive to muscarinic stimulation. However, following 3 days of co-culture with ciliary ganglia, the heart cells developed a negative chronotropic response to muscarinic stimulation (paired t test, P < 0.02) which persisted for at least 24 h after removal of the ciliary ganglion. The development of muscarinic responsiveness was associated with an increase in the levels of specific alpha-subunits of the guanine nucleotide binding proteins (G-proteins), with a 3-fold increase in the level of alpha 39 (39 kDa subunit) and a 2.5-fold increase in the level of alpha 41. The level of the G-protein subunit alpha s remained unchanged. Culture of embryonic chick heart cells at 3.5 days in ovo with medium conditioned by the growth of embryonic chick heart cells and ciliary ganglia had an effect on the chronotropic response to muscarinic stimulation and on alpha 39 and alpha 41 levels identical to that of co-culture. These data suggest that a soluble factor released during the co-culture of embryonic chick heart cells and ciliary ganglia is capable of inducing muscarinic responsiveness. These studies suggest that innervation of the heart may induce parasympathetic responsiveness by increasing the availability of G-proteins which couple the muscarinic receptor to a physiological response.

Potassium permeability of embryonic avian heart cells in tissue culture

1979 ◽  
Vol 236 (3) ◽  
pp. C163-C170 ◽  
Author(s):  
C. R. Horres ◽  
J. F. Aiton ◽  
M. Lieberman
Keyword(s):  
Membrane Permeability ◽  
Heart Cells ◽  
Embryonic Chick ◽  
Potassium Permeability ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
External Potassium ◽  
Free Media ◽  
The Relationship ◽  
Low K

The relationship between the external potassium concentration ([K]o) and membrane permeability has been reexamined using a tissue-cultured preparation of embryonic chick heart cells in which diffusional limitations are minimal. The unidirectional K efflux and electrochemical gradients were determined as a function of [K]o, and the results showed that potassium permeability was constant within the range of 1-20 mM [K]o. Membrane potentials were obtained in K-free solutions and correlated with 42K efflux and intracellular ion content measurements under the same conditions. In contrast to preparations of the intact embryonic chick heart, 42K efflux does not decrease in K-free media. Simulations of tracer measurements at reduced [K]o from naturally occurring cardiac muscle indicate that the experimentally observed decrease in 42K efflux could result from diffusional limitations. This observation, when coupled with the experimental results, suggests that the effect of low [K]o on membrane permeability in homeothermic preparations of cardac muscle should be reevaluated.

Acetylcholinesterase-acetylcholine, an enzyme system essential to rhythmicity in the preneural embryonic chick heart

1966 ◽  
Vol 154 (3) ◽  
pp. 675-683 ◽  
Author(s):  
George Hugo Paff ◽  
Robert Joseph Boucek ◽  
Thorne Parsons Glander
Keyword(s):  
Enzyme System ◽  
Embryonic Chick ◽  
Chick Heart ◽  
Embryonic Chick Heart
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