Electrophysiological properties of rat mesenteric lymphatic vessels and their regulation by stretch.
Electrophysiological properties of rat mesenteric lymphatic vessels and their regulation by stretch.
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大鼠肠系膜淋巴管的电生理特性及其拉伸调节。
DOI：
10.1089/lrb.2013.0045
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发表时间：
2014
影响因子：
1.4
通讯作者：
Davis,MichaelJ
中科院分区：
文献类型：
--
作者：
vonderWeid,Pierre-Yves;Lee,Stewart;Imtiaz,MohammadS;Zawieja,DavidC;Davis,MichaelJ
背景：在哺乳动物中，淋巴主要通过集合淋巴管的阶段性收缩（称为淋巴泵送）集中推进。在豚鼠和绵羊肠系膜淋巴管中进行的电生理学研究表明，收缩是由硝苯地平敏感的动作电位（AP）在淋巴肌中启动的。淋巴泵是高度敏感的管腔液体负荷和拉伸诱导泵的机械性能一直在研究，特别是在大鼠肠系膜淋巴管。然而，膜电位（Vm）和牵张诱导的淋巴泵的电生理事件尚未在大鼠中进行研究。因此，本研究的目的是检查大鼠肠系膜淋巴肌Vm在静息状态下的属性，并评估在Vm的变化所造成的膨胀。方法和结果：淋巴肌Vm测量尖锐的细胞内微电极无论是在未拉伸的条件下，或根据等距张力提供的线myograph。在未拉伸血管中，Vm为−48±2 mV（n=30）。AP（振幅<25 mV）以100/8/min的频率观察到，并被硝苯地平消除。在等长张力下，即使在最小张力下，Vm也较少极化（-36 1 mV，n=23）。张力的增加导致收缩强度和收缩/AP频率的增加，而Vm略有超极化和AP振幅没有显着altered.Conclusions：在我们的实验条件下，大鼠淋巴肌具有类似于其他物种的电生理特性。它响应于等长张力的增加，AP频率增加，但静息Vm没有显着影响。
Background:In mammals, lymph is propelled centrally primarily via the phasic contractions of collecting lymphatic vessels, known as lymphatic pumping. Electrophysiological studies conducted in guinea pig and sheep mesenteric lymphatic vessels indicate that contractions are initiated in the lymphatic muscle by nifedipine-sensitive action potentials (APs). Lymphatic pumping is highly sensitive to luminal fluid loading and the mechanical properties of this stretch-induced pumping have been consistently studied, in particular in rat mesenteric lymphatic vessels. However, membrane potential (Vm) and the electrophysiological events underlying stretch-induced lymphatic pumping have not been investigated in the rat. The aim of this study was thus to examine the properties of rat mesenteric lymphatic muscle Vm under resting conditions and to assess changes in Vm caused by distension.Methods and Results:Lymphatic muscle Vm was measured with sharp intracellular microelectrodes either in unstretched conditions or under isometric tension provided by a wire-myograph. In unstretched vessels, Vm was −48±2 mV (n=30). APs (amplitude ∼25 mV) were observed at a frequency of ∼8/min and were abolished by nifedipine. Under isometric tension, Vm was less polarized (-36±1 mV,n=23), even at minimum tension. Increase in tension led to increase in contraction strength and contraction/AP frequency, while Vm was slightly hyperpolarized and AP amplitude not markedly altered.Conclusions:In our experimental conditions, rat lymphatic muscle has electrophysiological characteristics similar to that in other species. It responds to an increase in isometric tension with an increase in AP frequency, but resting Vm is not significantly affected.