Intracellular Distribution of Calcium-45 in Arteries of Normal and Hypertensive Dogs ∗

Summary

The intracellular distribution of ⁴⁵Ca in arterial wall from normal and from experimentally hypertensive male mongrel dogs was studied, because indirect evidence suggests that the calcium ion has an important role in the maintenance of blood pressure, and because well-documented changes occur in the electrolyte and water composition of walls of arteries in hypertension. Chronic renal hypertension was created in 12 dogs by cellophane perinephritis. Arterial tissue was obtained under sodium pentobarbital anesthesia 2 hours after intravenous loading with ⁴⁵Ca. Tissue was obtained similarly from 7 sham operated control dogs and from 10 normal unoperated dogs. Arterial tissue was differentially centrifuged and the radioactivity of intracellular fractions was determined. Intracellular distribution in aorta and radial artery was similar to that in carotid artery. Mean percentage uptakes by the individual intracellular fractions in normal dog carotid artery were: 700g fraction, 26.9%; 5000g fraction, 20.1%; 123,000g fraction, 34.3%; 17-hour fraction, 18.6%. The intracellular distribution of ⁴⁵Ca was statistically similar in carotid artery in normal, control, and hypertensive dogs.