Changes in endothelial actin cytoskeleton in venules with time
after histamine treatment.
Baldwin, Ann L., and Gavin Thurston.
Department of Physiology, College of Medicine, University of
Arizona, Tucson, Arizona 85724, Tel: 602-626-6264, Fax: 602-626-2383,
Department of Ophthalmology, University of British Columbia, 2550
Willow St., Vancouver BC Canada, V5Z 3N9
APStracts 2:0193H, 1995.
In this study the time course of development and recovery of
histamine-induced venular leaks was followed in conjunction with
rearrangement of endothelial actin fibers. The microvasculature of a
single mesenteric window of anesthetized Sprague Dawley rats was
perfused with buffered saline, with or without 10 histamine, for 3-30
minutes. Fluoroscein isothiocyanate (FITC)-albumin was added for the
last 3 minutes. The microvasculature was perfusion fixed, stained
with rhodamine phalloidin (for filamentous actin), and viewed using
confocal microscopy. The number and relative size of FITC-albumin
leaks per venule length were measured. After 3 minutes histamine
focal leaks appeared in some of the venules. Most focal leaks were
accompanied by local breaks in the endothelial peripheral actin rim.
Larger leaks were also present, accompanied by greater disruption of
the venular endothelial peripheral actin rim, diffuse F-actin
staining, and adherent platelets and leukocytes. Few central actin
fibers were visible even in endothelial cells associated with large
leaks. After 10-15 minutes of histamine, larger leaks were more
abundant but with fewer adherent cells. Central actin fibers in
endothelial cells increased in number, peaking after 20 minutes of
histamine, while the diffuse actin staining declined. Leak area/[mu]m
of venule peaked at 10-15 minutes but the numbers of leaks/[mu]m did
not vary significantly from 3-30 minutes. These data suggest that the
central fibers are not involved with the phase of increasing
permeability, but they may play a role in the structural and
functional recovery of endothelial cells perturbed by histamine.
Received 27 December 1994; accepted in final form 25 April 1995.
APS Manuscript Number H1136-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 16 May 1995.