Signalling pathways involved in the short-term potentiation of dopamine release by BDNF

Brain-derived neurotrophic factor (BDNF) has been shown to modulate synaptic plasticity in the corpus striatum in vitro by activation of the tyrosine kinase linked receptor, TrkB. However, the signalling pathways that mediate this modulation of plasticity are poorly understood. Three proteins mediating signalling pathways are activated by the binding of BDNF to TrkB: phosphoinositol-3 kinase (PI3K); Ras-MEK and phospholipase C-gamma (PLCgamma). The present study investigates which of these pathways are necessary for BDNF-mediated potentiation of synaptic output of dopamine from slices and synaptosomes of rat corpus striatum. The results indicate that activation of the PI3K and Ras-MEK pathways, but not PLCgamma, are involved. Inhibitors of transcription and translation had no effect on the potentiation of depolarisation-stimulated (15 mM KCl) dopamine release mediated by BDNF.