TIRF imaging of quantal neuropeptide release from rodent primary sensory DRG neurons

【摘要】：Neuropeptide release plays important role in sensory and nociceptive information transmission in DRG neurons.However,this process has only been investigated using biochemical methods with limited temporal and spatial resolution.Thus the primary sites,kinetics and regulation of neuropeptide release remains unknown.Using real-time TIRF imaging,we examined neuropeptide release from cultured DRG neurons at the single-vesicle level for the first time.NPY-pHluorin was expressed in DRG neurons as a molecular marker of neuropeptide-containing dense-core vesicles(DCVs).Two types of events were identified.The main type exhibited full NPY-pHluorin release while the other type was characterized by rapid fusion pore opening-closures with confined NPY-pHluorin release.In addition to somatic release which has been identified before,we also recorded robust neuropeptide release from DRG neuron axon.DCV in the axon exhibited markedly higher release probabihty,faster release rate and shorter delay than soma although the calcium concentrations in axon was not higher.Noxius stimulation such as capsaicin directly evoked NPY-pHluorin release and modulate the fusion pore properties.These data suggested that neuropeptide release in DRG neurons was regulated by different cellular compartments and stimulations.