Choline up-regulates BDNF and down-regulates TrkB neurotrophin receptor in rat cortical cell culture

In this study, possible involvements of choline and nicotinic acetylcholine receptors (nAChRs) in neurotrophic-related neuronal plasticity were investigated. Primary cell cultures from rat cerebral cortex were exposed for 72 h to the alpha 7 nAChR selective agonist choline and protein expression levels of the neurotrophin receptors p75, TrkA, TrkB and TrkC were examined. The results revealed a choline-induced attenuation of the TrkB expression, whereas the other neurotrophin receptors were not affected. Further analysis of choline-exposed cell cultures showed an increased protein level of the TrkB ligand brain-derived neurotrophic factor (BDNF). This increase was obtained in cell cultures where the alpha 7 nAChR subunit was detected, but not in younger cell cultures where this subunit could not be detected. It is speculated that a choline-induced change of alpha 7 nAChRs activity may have resulted in the observed increase of BDNF level and down-regulation of the TrkB receptor. NeuroReport 20:828-832 (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.