Human native Ca_v1 channels in chromaffin cells: contribution to exocytosis and firing of spontaneous action potentials

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• 作者：Alicia Herná ; ndez-Vivanco^a ; Sara Sanz-Lá ; zaro^a ; Amanda Jimé ; nez-Pompa^a ; Nuria Garc&iacute ; a-Magro^a ; Beatriz Carmona-Hidalgo^a ; Alberto Pé ; rez-Alvarez^a ; Jose Carlos Caba-Gonzá ; lez^a ; Angel Tabernero^b ; Sergio Alonso y Gregorio^b ; Juan Passas^c ; Jesú ; s Blá ; zquez^d ; Carmen Gonzá ; lez-Enguita^e ; Cristina de Castro-Guer&iacute ; n^b ; Almudena Albillos^a ; ^{almudena.albillos@uam.es}
• 关键词：Cav1 channel ; Human ; Chromaffin cell ; Patch-clamp ; Exocytosis ; Action-potential
• 刊名：European Journal of Pharmacology
• 出版年：2017
• 出版时间：5 February 2017
• 年：2017
• 卷：796
• 期：Complete
• 页码：115-121
• 全文大小：838 K
• 卷排序：796

文摘

The present study was performed to evaluate the Cav1 channel subtypes expressed in human chromaffin cells and the role that these channels play in exocytosis and cell excitability. Here we show that human chromaffin cells obtained from organ donors express Cav1.2 and Cav1.3 subtypes using molecular and pharmacological techniques. Immunocytochemical data demonstrated the presence of Cav1.2 and Cav1.3 subtypes, but not Cav1.1 or Cav1.4. Electrophysiological experiments were conducted to investigate the contribution of Cav1 channels to the exocytotic process and cell excitability. Cav1 channels contribute to the exocytosis of secretory vesicles, evidenced by the block of 3 μM nifedipine (36.5±2%) of membrane capacitance increment elicited by 200 ms depolarizing pulses. These channels show a minor contribution to the initiation of spontaneous action potential firing, as shown by the 2.5 pA of current at the threshold potential (−34 mV), which elicits 10.4 mV of potential increment. In addition, we found that only 8% of human chromaffin cells exhibit spontaneous action potentials. These data offer novel information regarding human chromaffin cells and the role of human native Cav1 channels in exocytosis and cell excitability.