Ion Transport Characteristics in Rhesus Monkey Erythrocytes: Relationship to Age and Blood Pressure

Abstract

Erythrocyte (RBC) ion transport characteristics were examined in six young Rhesus monkeys (RM) age 3.3 ± .3 (x ± S.D.) years and seven mature RM 15.4 ± 1 (x ± S.D.) years. It was found that the older RM when compared to the younger RM demonstrated significantly elevated mean arterial pressures (MAP) (96 ± 15 versus 75 ± 11 mmHg), RBC intracellular sodiums (RBC Na) (16.2 ± 4 versus 11 ± 3 mEq/liter RBC) and NaK ATPase pump rates per RBC (PR) (PR = ouabain sensitive K uptake ÷ ouabain binding sites per RBC) (104 ± 18 versus 83 ± 18 K ions/sec/pump unit).

However, it was also found that when the data from both groups were pooled and collectively analyzed a significantly positive correlation could be found between MAP and RBC Na_i (p < .001, r = .82), MAP and PR (p <.01, r = .67) as well as PR and RBC Nai (p < .001, r = .76). The fact that positive correlations exist among these parameters, independent of age, would suggest that while MAP, RBC Na_i and PR tend to be elevated with advancing age, these abberrations are not invariable consequences of age and best reflect the pivotal abberration of rising Na_i. While insufficient data exist to account for the rise in Na_i and no cause-effect relationship can be established it is clear that rising MAP and PR correlate best with rising Na_i.

Key Words:

• Na
• K ATPase
• Intracellular Sodium
• Ouabain
• Aging
• Blood Pressure