Hypertension, Vol 6, 454-459, Copyright © 1984 by American Heart Association
R Bradlaugh, AM Heagerty, RF Bing, JD Swales and H Thurston
The wide range of membrane electrolyte transport abnormalities associated
with experimental, genetic, and essential hypertension may either reflect
an underlying global change in the cell membrane or may be directly related
to the underlying disturbance that causes hypertension or to changes in
sodium balance. To investigate this further, we studied sodium transport
and intracellular electrolyte composition in the thymocytes of normal rats
undergoing salt loading or depletion, and in rats with renovascular,
mineralocorticoid, or spontaneous hypertension compared to appropriate
age-matched normotensive control rats. In normotensive rats, although there
was no significant difference between the blood pressures at the two
extremes of sodium balance, sodium loading caused a nonsignificant rise in
sodium transport, whereas sodium depletion was associated with a
significant fall in sodium transport and intracellular sodium. When cells
from salt-loaded or normal animals were incubated in a medium containing
their own serum, sodium transport was slightly stimulated in both, but
there was no significant difference in the sodium efflux-rate constant of
thymocytes obtained from rats on the normal as opposed to the high salt
intake. Compared to normotensive rats, there was no significant change in
the sodium efflux-rate constant in any of the hypertensive rat models
studied. However, the sodium efflux-rate constant fell with age in both the
spontaneously hypertensive and Wistar-Kyoto normotensive rats. The present
studies show that dietary sodium intake and aging had considerable effects
on rat thymocyte sodium transport, but neither of these changes was related
to a change in blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
Rat thymocyte sodium transport. Effects of changes in sodium balance and experimental hypertension