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Sci Signal. 2017 Jun 20;10(484). pii: eaal1683. doi: 10.1126/scisignal.aal1683.

Ligand- and voltage-gated Ca2+ channels differentially regulate the mode of vesicular neuropeptide release in mammalian sensory neurons.

Author information

1
State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences, and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China.
2
State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences, and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China. changhewang@xjtu.edu.cn zzhou@pku.edu.cn.

Abstract

Neuropeptides released from dorsal root ganglion (DRG) neurons play essential roles in the neurotransmission of sensory inputs, including those underlying nociception and pathological pain. Neuropeptides are released from intracellular vesicles through two modes: a partial release mode called "kiss-and-run" (KAR) and a full release mode called "full fusion-like" (FFL). Using total internal reflection fluorescence (TIRF) microscopy, we traced the release of pH-sensitive green fluorescent protein-tagged neuropeptide Y (pHluorin-NPY) from individual dense-core vesicles in the soma and axon of single DRG neurons after Ca2+ influx through either voltage-gated Ca2+ channels (VGCCs) or ligand-gated transient receptor potential vanilloid 1 (TRPV1) channels. We found that Ca2+ influx through VGCCs stimulated FFL and a greater single release of neuropeptides. In contrast, Ca2+ influx through TRPV1 channels stimulated KAR and a pulsed but prolonged release of neuropeptides that was partially mediated by Dynamin 1, which limits fusion pore expansion. Suppressing the Ca2+ gradient to an extent similar to that seen after TRPV1 activation abolished the VGCC preference for FFL. The findings suggest that by generating a steeper Ca2+ gradient, VGCCs promote a more robust fusion pore opening that facilitates FFL. Thus, KAR and FFL release modes are differentially regulated by the two principal types of Ca2+-permeable channels in DRG neurons.

PMID:
28634208
DOI:
10.1126/scisignal.aal1683
[Indexed for MEDLINE]

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