Altered smooth muscle contraction and sodium pump activity in the inflamed rat intestine.
Altered smooth muscle contraction and sodium pump activity in the inflamed rat intestine.
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改变发炎大鼠肠道中的平滑肌收缩和钠泵活动。
DOI：
10.1152/ajpgi.1989.257.4.g570
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
S. Collins
中科院分区：
文献类型：
--
作者：
M. Muller;J. Huizinga;S. Collins
我们检查了 6 天前感染旋毛虫的大鼠空肠纵肌对卡巴胆碱的收缩力增加背后的膜功能变化。使用[N-甲基-3H]东莨菪碱 (NMS) 检查颗粒级分中的毒蕈碱受体特征。受感染大鼠肌肉上的结合位点总数显着减少，但对 NMS 的亲和力没有变化。同样，在竞争研究中，卡巴胆碱与高或低亲和力位点的结合在组织中与对照或感染大鼠没有显着差异。然而，我们观察到，与对照大鼠相比，感染者的质膜中 K+ 刺激的哇巴因敏感的对硝基苯磷酸酶 (pNPPase)（Na+ -K+ 泵的酶标记物）的活性受到 89% 的抑制。 86Rb 摄取研究中也获得了类似的结果。在收缩性研究中，通过证明 K+、Rb+ 或 Cs+ 引起的泵激活与组织松弛相关，其效力等级顺序与这些离子刺激 pNPPase 活性的顺序相同，从而获得了 Na+ -K+ 泵生电性的证据。相反，钒酸盐的泵抑制作用增加了对照或感染大鼠肌肉的张力并消除了肌肉的阶段性收缩。与此同时，对照大鼠的肌肉对卡巴胆碱的反应增强，但受感染的大鼠则没有。此外，通过去除细胞外 K 的泵抑制增加了对照组织的张力，但降低了螺旋毛虫感染大鼠的肌肉张力，这可能是由于先前存在的泵抑制。这些结果与抑制电钠泵活性有助于感染旋毛虫的大鼠空肠肌肉收缩性增加的假设相一致。
We examined changes in membrane function underlying the increased contractility of jejunal longitudinal muscle to carbachol in rats infected 6 days previously with Trichinella spiralis. Muscarinic receptor characteristics were examined in particulate fractions using [N-methyl-3H]scopolamine (NMS). There was a significant reduction in the total number of binding sites on muscle from infected rats, but the affinity for NMS was unchanged. Similarly, in competition studies, the binding of carbachol to high or low affinity sites was not significantly different in tissue from control or infected rats. However, we observed an 89% suppression of the activity of K+ -stimulated ouabain-sensitive p-nitrophenylphosphatase (pNPPase), an enzyme marker for the Na+ -K+ pump, in plasma membranes from infected compared with control rats. Similar results were obtained in 86Rb uptake studies. In contractility studies, evidence for the electrogenicity of the Na+ -K+ pump was obtained by demonstrating that pump activation by K+, Rb+, or Cs+ was associated with tissue relaxation with a rank order of potency that was identical to that for stimulation of pNPPase activity by these ions. Conversely, pump inhibition by vanadate increased tone and abolished phasic contractions in muscle from control or infected rats. This was accompanied by an increased response to carbachol in muscle from control but not infected rats. In addition, pump inhibition by removing extracellular K increased tone in control tissue but decreased tone in muscle from T. spiralis-infected rats, presumably because of preexisting pump suppression. These results are consistent with the hypothesis that suppression of electrogenic Na-pump activity contributes to the increased contractility of jejunal muscle in rats infected with T. spiralis.