title: Extracellular Ca²⁺ per se inhibits quantal size of catecholamine release in adrenal slice chromaffin cells.
abstract: Classic calcium hypothesis states that depolarization-induced increase in intracellular Ca(2+) concentration ([Ca(2+)]i) triggers vesicle exocytosis by increasing vesicle release probability in neurons and neuroendocrine cells. The extracellular Ca(2+), in this calcium hypothesis, serves as a reservoir of Ca(2+) source. Recently we find that extracellular Ca(2+)per se inhibits the [Ca(2+)]i dependent vesicle exocytosis, but it remains unclear whether quantal size is regulated by extracellular, or intracellular Ca(2+) or both. In this work we showed that, in physiological condition, extracellular Ca(2+) per se specifically inhibited the quantal size of single vesicle release in rat adrenal slice chromaffin cells. The extracellular Ca(2+) in physiological concentration (2.5 mM) directly regulated fusion pore kinetics of spontaneous quantal release of catecholamine. In addition, removal of extracellular Ca(2+) directly triggered vesicle exocytosis without eliciting intracellular Ca(2+). We propose that intracellular Ca(2+) and extracellular Ca(2+)per se cooperately regulate single vesicle exocytosis. The vesicle release probability was jointly modulated by both intracellular and extracellular Ca(2+), while the vesicle quantal size was mainly determined by extracellular Ca(2+) in chromaffin cells physiologically.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Shujiang
authors.initials: S
authors.lastname: Shang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Changhe
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Qihui
authors.initials: Q
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Quanfeng
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Lianghong
authors.initials: L
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Huadong
authors.initials: H
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Xinjiang
authors.initials: X
authors.lastname: Kang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Yeshi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Hui
authors.initials: H
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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.
authors.forename: Shirong
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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. Electronic address: weibear@gmail.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiong
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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. Electronic address: Liu_Tao@sbic.a-star.edu.sg.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology 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. Electronic address: zzhou@pku.edu.cn.
authors.forename: Zhuan
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000311:Adrenal Glands / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism*; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000166:cytology / Q000378:metabolism*; D005089:Exocytosis / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D022142:Secretory Vesicles / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D002118:Calcium
keywords: Amperometry; Catecholamine; Chromaffin cell; Extracellular Ca(2+); Quantal release