Asberg A, Holm T, Vassbotn T, Andreassen A K, Hartmann A
Department of Pharmacology, School of Pharmacy, University of Oslo, Norway.
Microvasc Res. 1999 Jul;58(1):41-8. doi: 10.1006/mvre.1999.2153.
Iontophoretic administration of acetylcholine chloride (ACh) and sodium nitroprusside (SNP) combined with laser Doppler skin blood perfusion measurements are used for determination of endothelial-dependent and -independent vasodilation. However, the method is biased by nonspecific vasodilation. The primary aim of this study was to investigate if iontophoresis-induced nonspecific vasodilation may be attenuated by addition of high molar concentrations of NaCl to the iontophoresis solutions. Secondary we investigated the applicability of 5 mol/liter NaCl solution as vehicle for ACh and SNP in this method. Skin perfusion changes were determined for iontophoresis of pure vehicles, deionized water and 5 mol/liter NaCl solution, in 12 healthy volunteers. Responses in skin perfusion to iontophoresis of ACh and SNP dissolved in both vehicles were also investigated. Addition of 5 mol/liter NaCl to deionized water significantly attenuated the nonspecific vasodilation and lowered the potential applied over the skin. The inter- and intraindividual coefficients of variation to ACh and SNP responses became, however, higher using hyperosmolar vehicle. During iontophoresis of SNP (in deionized water) we were unable to distinguish between SNP and vehicle effects. This study shows that the nonspecific vasodilation induced by iontophoresis can be attenuated by addition of 5 mol/liter NaCl, possibly due to lower electrical potential over the skin. However, the variability of the method was not improved. When deionized water was used as vehicle the effect of SNP could not be differentiated from that of the vehicle. This was not the case for ACh.
通过离子电渗法给予氯化乙酰胆碱（ACh）和硝普钠（SNP）并结合激光多普勒测量皮肤血流灌注，用于测定内皮依赖性和非内皮依赖性血管舒张。然而，该方法存在非特异性血管舒张的偏差。本研究的主要目的是调查在离子电渗溶液中添加高摩尔浓度的NaCl是否可以减弱离子电渗诱导的非特异性血管舒张。其次，我们研究了5摩尔/升NaCl溶液作为该方法中ACh和SNP载体的适用性。在12名健康志愿者中，测定了纯载体、去离子水和5摩尔/升NaCl溶液离子电渗时的皮肤灌注变化。还研究了皮肤对溶解于两种载体中的ACh和SNP离子电渗的反应。向去离子水中添加5摩尔/升NaCl可显著减弱非特异性血管舒张，并降低施加在皮肤上的电势。然而，使用高渗载体时，ACh和SNP反应的个体间和个体内变异系数变得更高。在SNP（溶解于去离子水中）离子电渗期间，我们无法区分SNP和载体的作用。本研究表明，添加5摩尔/升NaCl可减弱离子电渗诱导的非特异性血管舒张，这可能是由于皮肤表面较低的电势所致。然而，该方法的变异性并未得到改善。当使用去离子水作为载体时，无法区分SNP和载体的作用。ACh的情况并非如此。
