Li R, El-Mallakh RS. Differential response of bipolar and normal control lymphoblastoid cell sodium pump to ethacrynic acid.
J Affect Disord 2004;
80:11-7. [PMID:
15094253 DOI:
10.1016/s0165-0327(03)00044-2]
[Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2002] [Accepted: 12/30/2002] [Indexed: 11/16/2022]
Abstract
BACKGROUND
While the pathogenesis of manic-depressive, or bipolar, illness is unknown, an excess of intracellular sodium and calcium concentrations is thought to contribute to the development of the illness. Previous work has demonstrated a reduced adaptive response of the sodium pump to ethacrynic acid in lymphocytes obtained from bipolar subjects compared to psychiatrically normal controls.
METHODS
To further examine this phenomenon, we investigated several aspects of sodium pump response (transcription, translation, activity, and intracellular ion concentration) in lymphoblastoid cell lines derived from bipolar subjects and matched normal controls. Cells were treated with ethacrynic acid 100 microM for 3 days.
RESULTS
Normal control-derived cells exhibited an upregulation of sodium pump mRNA synthesis, protein expression, pump-specific binding and activity, and were able to maintain a normal intracellular sodium concentration. Cells derived from bipolar individuals did not alter sodium pump parameters in any way, and consequently, had a higher intracellular sodium concentration.
LIMITATIONS
While bipolar lymphoblasts were from an inbred Old Order Amish population, the normal controls were from an outbred population.
CONCLUSIONS
The results suggest that bipolar illness is associated with an abnormality in cellular sodium homeostatic regulation.
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