Bipolar Research Today is a free monthly online journal that collates and summarizes the latest research about Bipolar, including details on bipolar disorder, symptoms, treatment, depression, medication.

Chronic treatment with mood stabilizers increases membrane GRK3 in rat frontal cortex.

Ertley RN, Bazinet RP, Lee HJ, Rapoport SI, Rao JS

Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.

BACKGROUND: G-protein receptor kinases (GRKs) are a family of serine/threonine kinases involved in the homologous desensitization of agonist activated G-protein coupled receptors (GPCRs). G-protein coupled receptor supersensitivity, possibly as a result of decreased GRK, has been suggested in affective disorders. METHODS: We used immunobloting to determine if chronic, therapeutically relevant doses of lithium (Li+), carbamazepine (CBZ), and valproate (VPA), would increase GRK2/3 protein levels in rat frontal cortex. RESULTS: Chronic Li+ (24%) and CBZ (44%) significantly increased GRK3 in the membrane but not cytosol fractions. Chronic VPA had no effect on GRK3. G-protein receptor kinase 2 protein levels were unchanged by all treatments. The GRK3 membrane to cytosol ratio was increased significantly in Li+ and CBZ treated rats. CONCLUSIONS: These results show that chronically administered Li+ and CBZ, but not VPA, increase the translocation of GRK3 from cytosol to membrane, possibly correcting supersensitivity of GPCRs in bipolar disorder.

Published 15 January 2007 in Biol Psychiatry, 61(2): 246-9.
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