Soares J C, Mallinger A G, Dippold C S, Frank E, Kupfer D J
Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pennsylvania, USA.
Biol Psychiatry. 1999 Feb 15;45(4):453-7. doi: 10.1016/s0006-3223(98)00048-1.
Abnormalities in cell membrane processes and intracellular signal transduction pathways may be implicated in the pathophysiology of bipolar disorder. In this study, we attempted to investigate, in euthymic bipolar patients: 1) in vivo signal transduction abnormalities of the phosphatidylinositol pathway in platelets; and 2) possible in vivo effects of lithium treatment on platelet membrane phospholipids.
We determined the relative absorbances of eight individual classes of platelet membrane phospholipids, using two-dimensional thin-layer chromatography in high-performance plates, followed by scanning laser densitometry, in a group of 10 lithium-treated euthymic bipolar patients and 11 normal controls.
The mean relative absorbance of phosphatidyl-inositol-4,5-bisphosphate (PIP2) was lower in the patient group (0.29 +/- 0.08% vs. 0.39 +/- 0.12%; t = 2.35, df = 19, p = .03); no significant differences between patients and controls were found for the other phospholipids.
This study provides in vivo evidence that bipolar patients on lithium treatment exhibit a decreased relative amount of PIP2 in the platelet cell membranes compared to normal controls.
