AJP - Cell Physiology, Vol 233, Issue 3 74-C85, Copyright © 1977 by American Physiological Society
Protein transport across cerebral vessels during metrazole-induced convulsions
E. T. Hedley-Whyte, A. V. Lorenzo and D. W. Hsu
The effects of pentylenetetrazole-induced convulsions on cerebrovascular
permeability for horseradish peroxidase were studied in locally
anesthetized, artificially respired, paralyzed cats. Horseradish peroxidase
circulated for 1, 2.5, 5, 10, 30, and 60 min and accumulated in
medium-size, i.e., arterial or venous, blood vessel walls. Cerebral
neuropil was permeated earliest in thalamic nuclei including medial and
lateral geniculate nuclei. No tight junctions containing horseradish
peroxidase were found. With 1.0 and 2.5 min circulation of horseradish
peroxidase, arterial adventitia and basement membranes contained more
peroxidase than surrounding interstitial space in contrast to veins and
capillaries. Convulsions increased the number of endothelial vesicles
containing horseradish peroxidase in arteries, veins, and capillaries but
total number (stained plus unstained) of endothelial vesicles was increased
slightly only in capillaries. We conclude that increased permeability is
initially at the arterial level, although veins may also become permeable.
The role of the endothelial vesicles in transit or protein in and out of
the nervous system is not clear.
