Author/Editor		Kleiman, Robin J; Tian, Ning; Križaj, David; Hwang, Thomas N; Copenhagen, David R; Reichardt, Louis F
Title		BDNF-Induced potentiation of spontaneous twitching in innervated myocytes requires calcium release from intracellular stores
Type		članek
Source		J Neurophysiol
Vol. and No.		Letnik 84, št. 1
Publication year		2000
Volume		str. 472-83
Language		eng
Abstract		Brain-derived neurotrophic factor (BDNF) can potentiate synaptic release at newly developed frog neuromuscular junctions. Although this potentiation depends on extracellular Ca(2+) and reflects changes in acetylcholine release, little is known about the intracellular transduction or calcium signaling pathways. We have developed a video assay for neurotrophin-induced potentiation of myocyte twitching as a measure of potentiation of synaptic activity. We use this assay to show that BDNF-induced synaptic potentiation is not blocked by cadmium, indicating that Ca(2+) influx through voltage-gated Ca(2+) channels is not required. TrkB autophosphorylation is not blocked in Ca(2+)-free conditions, indicating that TrkB activity is not Ca(2+) dependent. Additionally, an inhibitor of phospholipase C interferes with BDNF-induced potentiation. These results suggest that activation of the TrkB receptor activates phospholipase C to initiate intracellular Ca(2+) release from stores which subsequently potentiates transmitter release.
Descriptors		ACTION POTENTIALS ANIMALS BRAIN-DERIVED NEUROTROPHIC FACTOR CADMIUM CALCIUM CALCIUM CHANNELS ENZYME INHIBITORS ESTRENES INDOLES MOTOR NEURONS MUSCLE CONTRACTION OOCYTES PC12 CELLS PHOSPHODIESTERASE INHIBITORS PHOSPHORYLATION PHOSPHOTYROSINE PYRROLIDINONES RATS SYNAPSES THAPSIGARGIN TYROSINE XENOPUS