Elemental maps in human allantochorial placental vessels cells: 1. High K⁺ and acetylcholine effects

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• 作者：Michelet-Habchi ; C. ; Barberet ; Ph. ; Dutta ; R.K. ; Guiet-Bara ; A. ; Bara ; M. ; Moretto ; Ph.
• 关键词：61.16.&minus ; d ; 87.64.&minus ; t ; Placental vessels ; Acetylcholine ; Ionic channels ; Microanalysis ; Micro-PIXE ; Scanning proton microprobe
• 刊名：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• 出版年：2003
• 出版时间：September, 2003
• 年：2003
• 卷：210
• 期：Complete
• 页码：354-358
• 全文大小：258 K

文摘

Regulation of vascular tone in the fetal extracorporeal circulation most likely depends on circulating hormones, local paracrine mechanisms and changes in membrane potential of vascular smooth muscle cells (VSMCs) and of vascular endothelial cells (VECs). The membrane potential is a function of the physiological activities of ionic channels (particularly, K⁺ and Ca²⁺ channels in these cells). These channels regulate the ionic distribution into these cells. Micro-particle induced X-ray emission (PIXE) analysis was applied to determine the ionic composition of VSMC and of VEC in the placental human allantochorial vessels in a physiological survival medium (Hanks’ solution) modified by the addition of acetylcholine (ACh: which opens the calcium-sensitive K⁺ channels, K_Ca) and of high concentration of K⁺ (which blocks the voltage-sensitive K⁺ channels, K_df). In VSMC (media layer), the addition of ACh induced no modification of the Na, K, Cl, P, S, Mg and Ca concentrations and high K⁺ medium increased significantly the Cl and K concentrations, the other ion concentrations remaining constant. In endothelium (VEC), ACh addition implicated a significant increase of Na and K concentration, and high K⁺ medium, a significant increase in Cl and K concentration. These results indicated the importance of K_df, K_Ca and K_ATP channels in the regulation of K⁺ intracellular distribution in VSMC and VEC and the possible intervention of a Na–K–2Cl cotransport and corroborated the previous electrophysiological data.