Short-term response of postnatal rat vestibular neurons following brain-derived neurotrophic factor or neurotrophin-3 application

The effects of the application of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) neurotrophins on the intracellular calcium level ([Ca2+](i)) were studied in vestibular ganglion neurons (VGNs) from postnatal slay 3 (P3) rats cultured for 50 hr, We first assessed the expression of trkB and trkC mRNA receptors in cultured VGNs, Immunobloting and immunocytochemistry confirmed the presence of the neurotrophin receptors on neurons, Both neurotrophins induced transient [Ca2+](i) elevations in VGNs: BDNF-treated neurons responded in 65% and NT-3-treated neurons in 56%, The responses could be inhibited by anti-BDNF or anti-NT-3 antibodies, The [Ca2+](i) elevation was dependent on extracellular calcium since it was abolished in calcium-free medium but also implicates the release of calcium from intracellular stores as tested by prior depletion with thapsigargin, Our results suggest the implication of a shortterm calcium regulation in VGNs, which could reflect specific fast effects of neurotrophins in the early postnatal rat vestibular system. (C) 1997 Wiley-Liss, Inc.