动脉平滑肌和胶原蛋白对去甲肾上腺素的神经元外摄取的摄取动力学及离子需求

Uptake kinetics and ion requirements for extraneuronal uptake of noradrenaline by arterial smooth muscle and collagen.

Gillespie J S, Towart R

Br J Pharmacol. 1973 Mar;47(3):556-67. doi: 10.1111/j.1476-5381.1973.tb08186.x.

Abstract

The ionic requirements for noradrenaline uptake into vascular smooth muscle cells were studied by perfusing rabbit isolated ear arteries with noradrenaline (10(-3)M) either in Krebs solution or in Krebs solution modified by altering the concentration of one or more ion. Noradrenaline uptake was measured by quantitative microphotometry.2. Some uptake into smooth muscle continued in isotonic sucrose in the absence of all ions. Omission of Na(+) from the Krebs solution partially inhibited uptake as did high (100 mM) K(+). Omission of K(+), Ca(++) or Mg(++) had no effect on uptake. Lithium was able completely to substitute for Na(+).3. Alteration in ion concentration did not affect the binding of noradrenaline to collagen.4. The kinetics of uptake of noradrenaline into smooth muscle were analysed and found to be saturable with a Km of 4.9 x 10(-4)M.5. It is concluded that the ionic requirements of the transport mechanism for the uptake of noradrenaline by vascular smooth muscle show a relatively low specificity.

摘要

通过用去甲肾上腺素（10⁻³M）灌注兔离体耳动脉来研究血管平滑肌细胞摄取去甲肾上腺素的离子需求，去甲肾上腺素分别存在于 Krebs 溶液中或通过改变一种或多种离子浓度而改良的 Krebs 溶液中。去甲肾上腺素摄取量通过定量显微光度测定法进行测量。
在没有所有离子的情况下，在等渗蔗糖中平滑肌仍有一些摄取。从 Krebs 溶液中去除 Na⁺ 会部分抑制摄取，高浓度（100 mM）的 K⁺ 也会如此。去除 K⁺、Ca²⁺ 或 Mg²⁺ 对摄取没有影响。锂能够完全替代 Na⁺。
离子浓度的改变不影响去甲肾上腺素与胶原蛋白的结合。
对去甲肾上腺素摄取到平滑肌中的动力学进行了分析，发现其具有饱和性，Km 为 4.9×10⁻⁴M。
得出结论，血管平滑肌摄取去甲肾上腺素的转运机制的离子需求显示出相对较低的特异性。