D. A. T. Dick

Erythrocyte membrane cation carrier in manic-depressive psychosis

Erythrocyte Na-K ATPase and sodium pump site numbers were estimated in groups of depressed, manic and recovered patients. The activity of Na-K ATPase per pump site was lower in the depressed group than in the recovered group. In the manic group Na-K ATPase was lower than that of the recovered group, whereas there was no difference in the pump site numbers. In the more severe manics the activity of Na-K ATPase per pump site was significantly lower than that of the recovered patients. Therefore, the change occurring in the erythrocyte membrane cation carrier in manic-depressive psychosis is probably in the activity of individual Na-K ATPase molecules and not in the number of Na-K ATPase molecules per cell.

Lithium therapy and erythrocyte membrane cation carrier

Plasma cortisol and erythrocyte Na-K ATPase, ouabain sensitive K+ influx, lithium, sodium and potassium concentrations were measured twice when patients were on placebo and twice when they were on lithium therapy. The erythrocyte Na-K ATPase was significantly higher during the lithium than during the placebo treated period, whereas the other biochemical values measured showed no significant difference between the two phases.

Erythrocyte membrane cation carrier in mania.

Erythrocyte sodium and potassium concentrations, erythrocyte membrane ATPase (Na-K specific and non-specific) and the rate of potassium influx into erythrocytes (ouabain-sensitive and insensitive) were estimated in a group of female patients suffering from mania and repeated on about two thirds of them when they had recovered. With recovery there was a statistically significant increase in the erythrocyte ouabain-sensitive potassium influx. The other parameters showed no significant overall change with recovery but the initial severity correlated significantly and negatively with the change in erythrocyte Na-K ATPase with recovery. The changes that occurred in the erythorcyte sodium concentration and Na-K ATPase activity were not random since they correlated significantly with changes in the active potassium influx.

Plasma vanadium concentration in manic-depressive illness.

133 samples of plasma taken from 9 normal control and 8 manic-depressive subjects were analysed for vanadium by atomic absorption spectrometry. Mean plasma vanadium concentrations were 0 . 15 microM in normal control, 0 . 34 microM in manic and 0 . 28 microM in depressed subjects, and 0 . 23 microM in manic-depressive subjects after recovery. The differences between normal subjects and manic and recovered subjects were statistically significant. Significant negative correlations were found between plasma vanadium concentration and the ratio of Na-K-Mg ATPase to Mg-ATPase in 2 manic-depressive subjects, but not in normal subjects. The results suggest that vanadium may be a cause of the variations in Na-K-Mg ATPase and sodium pump activity which are associated with manic-depressive illness.

Erythrocyte membrane cation carrier, relapse rate of manic-depressive illness and response to lithium.

Biochemical studies of manic-depressive psychosis usually correlates biochemical findings with current affective state and hence any significant findings could be secondary to mood change. The present study attempts to correlate measures of the erythrocyte membrane cation carrier with clinical events, remote in time from the biochemical assay. Eprythrocyte sodium concentration, ouabain-sensitive potassium influx and Na-K ATPase were estimated in 11 patients before and after the cross-over point in a 2-year double blind clinical trial ratio tended to suffer most episodes of affective illness in the 2 years. Patients who had a low initial Na-K ATPase or a high initial flux sodium ATPase ratio, or in whom this ratio fell most with lithium or whose Na-K ATPase rose most with lithium, clinically responded best to lithium.

Lithium and erythrocyte membrane cation carrier studies in normal and manic depressive subjects.

Changes in the erythrocyte membrane cation carrier following lithium ingestion in normal human subjects were studied; ouabain sensitive potassium influx fell significantly during the lithium treated phase. Lithium was fed to rats and no change in erythrocyte Na-K ATPase was shown. These findings contrast with studies of lithium in manic depressive psychosis. The fluctuations in the erythrocyte membrane cation carrier were studied in 5 normal subjects over 12 weeks and the correlations between the parameters calculated. The erythrocyte sodium concentration correlated positively with the ouabain sensitive potassium influx. This too contrasts with findings in manic depressive psychosis.

Changes in the Erythrocyte Sodium Pump with Age

Various estimations of the erythrocyte sodium pump were determined in 18 female and 11 male adult subjects. In the female group, but not in the male group, the sodium concentration increased with age; the erythrocyte active transport decreased and passive transport increased with age and could account for the observed change in erythrocyte sodium concentration with age. The erythrocyte Na-K ATPase decreased with age in the females and this could account for the observed change in active transport.

Changes in Erythrocyte Membrane Cation Carrier with Age in Women

Erythrocyte Na-K ATPase and specific ouabain binding (sodium pump site numbers) were estimated in 21 normal female subjects. The Na-K ATPase activity and the number of pump sites in the older women were significantly lower than those of the younger women, but there was no evidence of change in activity at individual pump sites. When divided into pre- and post-menopausal groups there was no correlation within each group between biochemical parameters and age.