AJP - Heart and Circulatory Physiology, Vol 261, Issue 3 627-H631, Copyright © 1991 by American Physiological Society
Effect of local pH on interstitial fluid pressure
M. Gilanyi and A. G. Kovach
Experimental Research Department, Semmelweis University Medical School, Budapest, Hungary.
It has been suggested that electrostatic interactions between the electric
charges on the interstitial gel matrix play a significant role in
determining tissue elasticity and interstitial fluid pressure (IFP). The
relationship between the net charge and IFP, however, has not been
adequately established. Our purpose was to explore the net electric
charge-IFP relationship, and in vivo experiments were performed to test its
validity. IFP was measured in the subcutaneous tissue of anesthetized rats
with the chronically implanted capsule method, and the acid-base status in
blood and interstitial fluid was monitored. The net charge, which can be
varied by pH, was altered by electrolysis procedure. H+ and OH- generated
inside the capsule caused transient and dose-dependent IFP responses. The
curve, describing the relationship between capsular pressure changes and
amount of generated H+ and OH-, has a maximum at zero net charge, and the
excess electric charge, either positive or negative, results in a
significant decrease in capsular pressure in accordance with the
hypothesis. The time course, as well as the dose dependency, of IFP
suggests that the subcutaneous tissue gel in control condition has slightly
positive net charge.
