Tissue cations and water in arterial hypertension

Human hypertensive subjects were found to have an increased sodium and water concentration in renal artery and psoas muscle. Hypertensive rats showed a high water content in their aortas. If the water and sodium content were increased in hypertensive arterioles as well as arteries, the swelling of the arteriolar walls would narrow the lumens enough to account for much of the increased peripheral resistance. Low sodium diets may alleviate hypertension by lowering the sodium and water contents in arteriolar walls toward normal values.

Aorta electrolytes of hypotensive potassium-deficient rats

The hypotension of potassium-deficiency is associated with a decrease in aorta potassium concentration, the sodium content remaining unchanged, resulting in a high sodium/potassium ratio. Loss of arterial tone may result and thus contribute to the lowering of blood pressure. Cortisone administration to such rats does not alter the low aorta potassium content but appreciably reduces the sodium concentration. The return to a more normal sodium/potassium ratio in the aorta following cortisone may restore the arterial tone and thus explain the blood pressure rise to normal levels.

An enzymatic ion exchange model for active sodium transport

An enzymatic ion exchange model for active sodium transport is described. Kinetic equations relating net flux to time, and to concentration difference across the actively transporting membrane are derived. The second of these equations is tested, using the isolated frog skin in the "short-circuit" apparatus of Ussing. Reasonable linearity, as predicted by this equation, is observed. The passive permeability coefficient for Na(+), is calculated as 5.3 x 10(-4) +/- 5.3 x 10(-4) cm./hr. If cholinesterase is assumed to be the enzyme responsible for transport, the activity required to account for the observations reported here is 17.7 x 10(-4) mmoles/cm.(2)/hr.