Aim: 

Disturbances in several distinct cell membrane ion transport processes have been demonstrated in essential hypertension. Studies on altered activity of the Na⁺/K⁺ pump in blood cells have provided conflicting results regarding its involvement in essential hypertension. The purpose of the study was to evaluate the relationship of cellular Na⁺ transport in blood cells and essential hypertension after blocking the Na⁺/K⁺ pump with low temperature.

Methods: 

Eighty-three 60-year-old men were investigated. Blood pressure was measured according to the standard requirement. Two heparinised blood samples from normotensive (n = 27) and hypertensive (n = 59) men were collected to investigate Na⁺ concentration in blood plasma (AVL ISE Analysator). One of the samples (blood sample I) was examined immediately and the second (blood sample II) was stored for 4 h at 1°C temperature to show altered Na⁺ transport across the erythrocyte membrane by blocking the activity of the Na⁺/ K⁺ pump with low temperature.

Results: 

Systolic blood pressure of hypertensive men was 157.51 ± 20.73, and diastolic was 93.08 ± 9.86. Na⁺ concentration in blood sample I of hypertensive men was significantly higher than it was in normotensive men (142.89 ± 1.83 and 141.19 ± 1.36 resp., p = 0.0002). Na⁺ concentration after storing the blood sample at low temperature significantly decreased in hypertensive men (135.7 ± 25.68 in blood sample II compared to 142.51 ± 1.71 in blood sample I, p = 0.04).

Conclusion: 

We evaluated impaired sodium transport across the erythrocyte membrane of hypertensive men after blocking the Na⁺/K⁺ pump with low temperature and estimated the relationship between altered sodium transport and essential hypertension. Our results support the hypothesis that essential hypertension is a "cell membrane" disease.