AJP - Heart and Circulatory Physiology, Vol 243, Issue 2 307-H317, Copyright © 1982 by American Physiological Society
Intra-arterial histamine increases blood-brain transport in rats
P. M. Gross, G. M. Teasdale, D. I. Graham, W. J. Angerson and A. M. Harper
The neurotransmitter histamine is located in multiple compartments in the
brain and may influence cerebral vessels during some conditions. We made
measurements of cerebrovascular transport of labeled sucrose,
alpha-aminoisobutyric acid (AIB), and horseradish peroxidase during
sustained infusion of histamine into the internal carotid artery of
anesthetized rats. Histamine increased the rates of transport of sucrose
and AIB up to 237% in several brain regions and in different areas of
cerebral cortex. The effect was dose dependent, was reversible within 2 h,
and was mediated primarily by histamine H2-receptors. An increase in
cortical water content occurred, and electron microscopic examination
revealed that perivascular astroglial processes were swollen. There was a
twofold increase in the number of endothelial pits and vesicles in cortical
capillaries perfused by histamine. We conclude that histamine can influence
the function of the blood-brain barrier.
