title: Two distinct vesicle pools for depolarization-induced exocytosis in somata of dorsal root ganglion neurons.
abstract: The somata of dorsal root ganglion (DRG) neurons release neurotransmitters and neuropeptides. In addition to the conventional Ca2+-dependent secretion (CDS), Ca2+-independent but voltage-dependent secretion (CIVDS) also occurs in the somata of DRG neurons. Electrical stimulation induces both CDS and CIVDS, which differ in size and are coupled with different types of endocytosis contributed by CIVDS and CDS, respectively. However, it is unclear whether they use a common vesicle pool, so we investigated the relationship between the vesicle pools of CDS and CIVDS. Membrane capacitance recording and photolysis of a caged-Ca2+ compound showed that, in low external Ca2+ solutions, the depolarization-induced exocytosis contained two (fast and slow) phases, which were contributed by CIVDS and CDS, respectively. Depletion of the CDS readily releasable pool using photolysis did not affect the CIVDS. When the CIVDS and CDS vesicle pools were depleted by electrical stimulation, the pools had different sizes. Their kinetics of exocytosis-coupled endocytosis were also different. Thus, CIVDS and CDS used different vesicle pools in DRG neurons.
authors.affiliation: State Key Laboratory of Biomembrane Engineering, Institute of Molecular Medicine, Peking University, Beijing 100871, China. tao.liu06@gmail.com
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Shu-Jiang
authors.initials: SJ
authors.lastname: Shang
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Chang-He
authors.initials: CH
authors.lastname: Wang
authors.forename: Ye-Shi
authors.initials: YS
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Xiong
authors.forename: Liang-Hong
authors.initials: LH
authors.lastname: Zheng
authors.forename: Claire Xi
authors.initials: CX
authors.lastname: Zhang
authors.forename: Zhuan
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D025802:Electric Capacitance; D004705:Endocytosis / Q000502:physiology; D005089:Exocytosis / Q000502:physiology*; D005260:Female; D005727:Ganglia, Spinal / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D022142:Secretory Vesicles / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D018377:Neurotransmitter Agents; D002118:Calcium