CORRELATION BETWEEN BLOOD PRESSURE AND PLASMA MONOVALENT CATIONS AND THEIR RENAL EXCRETION IN HYPERTENSIVE PATIENTS AT PSYCHOEMOTIONAL STRESS

Abstract

Objective . To study the impact of psycho-emotional stress (PES) on the correlation between blood pressure (BP) and plasma sodium and potassium ions, and their renal excretion in patients with arterial hypertension (HTN). Design and methods. We examined 18 men with normal BP and 20 men with HTN of the second stage (mean age in both groups — 57 ± 3 years) who were exposed to PES. All the subjects responded by the increase in BP, pulse, diuresis, natriuresis, renal excretion of K+, clearance from Na+-CNa+. We evaluated Na+ and K+ by the flame photometer Flafo-40 (Germany), and the activity of plasma Na+ and K+ by potentiometric method with ion-selective minielectrodes ISE-M-K and the ISE-M-Na. Results. At PES, neither normotensives nor HTN patients showed any correlation between BP and either plasma sodium ions or their renal excretion. BP correlated negatively only with renal excretion of potassium ions in normotensives: the higher systolic (SBP) and diastolic (DBP) BP at all stages of the experiment (5 ties: –0,57, –0,52, –0,64, –0,56, –0,54) the lower renal excretion of potassium after PES. Normotensive subjects showed no correlation between BP and plasma potassium ions. Unlike the normotensive subjects, patients with HTN had no correlation between BP and renal excretion of potassium ions. However, patients with HTN showed negative correlation between BP (especially systolic) and plasma potassium ions: the higher SBP at baseline and at PES exposure (–0,42, –0,51), the lower the baseline concentration of plasma potassium. The higher SBP at all three stages of the experiment, the lower active potassium at baseline and at PES exposure (5 relations: –0,52, –0,45, –0,46, –0,53, –0,48). The higher SBP and DBP during and after PES exposure, the lower the coefficient of activity of potassium at PES (4 relations, –0,58, –0,47, –0,58, –0,45). Conclusions. 1) Correlation between BP and plasma sodium ions and renal sodium excretion was absent in both normotensives and HTN patients at PES exposure. 2) BP elevation negatively correlated with the renal excretion of potassium ions in normotensive subjects during PES exposure. 3) BP increase negatively correlated with the plasma potassium ions (potassium ions, active potassium and its coefficient of activity) in hypertensive patients during the PES. 4) In normotensive subjects BP negatively correlated only with the renal excretion of potassium ions during the PES. In HTN patients BP correlated negatively only with potassium ions, active potassium and potassium coefficient of activity. 5) Potassium ions play a significant role in the BP regulation and the mechanisms are different in normotensive and hypertensive individuals.