TY - JOUR
T1 - The control of pigment migration in isolated erythrophores of holocentrus ascensionis (Osbeck). II. The role of calcium
AU - Luby-Phelps, Katherine
AU - Porter, Keith R.
N1 - Funding Information:
We would like to thank George Wray for his help with the high-voltage electron microscopy, Joyce Albersheim for her assistance with the preparation of this manuscript and Dr. John C. Gilkey for many helpful discussions of the work and for providing the calculator program for setting up the Ca-EGTA buffer system. This work was supported by a grant to K. Ft. P. from the Muscular Dystrophy Association.
PY - 1982/6
Y1 - 1982/6
N2 - The integumental pigment cells (erythrophores) of the squirrel fish, Holocentrus ascensionis, are specialized for rapid radial transport of the pigment granules contained within their cytoplasm. Pigment granules in isolated denervated erythrophores alternate spontaneously between a centrally aggregated state and a radially dispersed state. In the absence of external calcium, pigment aggregation does not occur spontaneously and cannot be induced by the aggregating agents epinephrine or high concentration of external K+. Pigment aggregation is also impaired in the presence of D600 or papaverine, compounds reported to antagonize calcium influx into the cell. Pigment aggregation can be induced by experimental elevation of the concentration of cytoplasmic free Ca2+, with a Ca-EGTA buffer system in conjunction with ionophore A23187. The threshold concentration of Ca2+ required to produce this effect is 5 × 10-5 M. These results suggest that cytoplasmic free Ca2+ is involved in mediating pigment aggregation and that some, if not all, the Ca2+ is supplied by influx from the extracellular space.
AB - The integumental pigment cells (erythrophores) of the squirrel fish, Holocentrus ascensionis, are specialized for rapid radial transport of the pigment granules contained within their cytoplasm. Pigment granules in isolated denervated erythrophores alternate spontaneously between a centrally aggregated state and a radially dispersed state. In the absence of external calcium, pigment aggregation does not occur spontaneously and cannot be induced by the aggregating agents epinephrine or high concentration of external K+. Pigment aggregation is also impaired in the presence of D600 or papaverine, compounds reported to antagonize calcium influx into the cell. Pigment aggregation can be induced by experimental elevation of the concentration of cytoplasmic free Ca2+, with a Ca-EGTA buffer system in conjunction with ionophore A23187. The threshold concentration of Ca2+ required to produce this effect is 5 × 10-5 M. These results suggest that cytoplasmic free Ca2+ is involved in mediating pigment aggregation and that some, if not all, the Ca2+ is supplied by influx from the extracellular space.
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U2 - 10.1016/0092-8674(82)90160-X
DO - 10.1016/0092-8674(82)90160-X
M3 - Article
C2 - 6811138
AN - SCOPUS:0019971762
SN - 0092-8674
VL - 29
SP - 441
EP - 450
JO - Cell
JF - Cell
IS - 2
ER -