AJP - Cell Physiology, Vol 263, Issue 4 C908-C912, Copyright © 1992 by American Physiological Society
Vasopressin decreases immunogold labeling of apical actin in the toad bladder granular cell
Y. Gao, N. Franki, F. Macaluso and R. M. Hays
Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461.
Studies with the confocal microscope have shown that arginine vasopressin
(AVP) depolymerizes F-actin in the apical region of the toad bladder
granular cell. However, the resolution of the fluorescence microscope is
not great enough to reveal the exact pattern of depolymerization or the
relative extent to which microvillar and subapical membrane actin pools
contribute to overall depolymerization. We have developed an electron
microscopic immunogold method that shows a significant decrease in
immunogold labeling of actin in the region just below the apical membrane,
with the decrease most pronounced in regions adjacent to the microvilli.
There was no significant change of immunogold labeling within the
microvilli themselves. Our studies show a reorganization of the actin
cytoskeleton in the region of the granular cell, where water
channel-carrying vesicles are positioned and fuse in response to AVP.
