Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes 2415, São Paulo, Brazil.
World J Gastroenterol. 2010 Aug 7;16(29):3651-63. doi: 10.3748/wjg.v16.i29.3651.
To investigate the effects of malnutrition and re-feeding on the P2X(2) receptor, nitric oxide synthase (NOS), calretinin, calbindin and choline acetyltransferase (ChAT) in neurons of the rat ileum.
We analyzed the co-localization, numbers and sizes of P2X(2)-expressing neurons in relation to NOS-immunoreactive (IR), calbindin-IR, ChAT-IR, and calretinin-IR neurons of the myenteric and submucosal plexus. The experimental groups consisted of: (1) rats maintained on normal feed throughout pregnancy until 42 d post-parturition (N); (2) rats deprived of protein throughout pregnancy and 42 d post-parturition (D); and (3) rats undernourished for 21 d post-parturition and then given a protein diet from days 22 to 42 (DR). The myenteric and submucosal plexuses were evaluated by double labeling by immunohistochemical methods for P2X(2) receptor, NOS, ChAT, calbindin and calretinin.
We found similar P2X(2) receptor immunoreactivity in the cytoplasm and surface membranes of myenteric and submucosal neurons from the N, D and DR groups. Double labeling of the myenteric plexus demonstrated that approximately 100% of NOS-IR, calbindin-IR, calretinin-IR and ChAT-IR neurons in all groups also expressed the P2X(2) receptor. In the submucosal plexus, the calretinin-IR, ChAT-IR and calbindin-IR neurons were nearly all immunoreactive for the P2X(2) receptor. In the myenteric plexus, there was a 19% increase in numbers per cm(2) for P2X(2) receptor-IR neurons, 64% for NOS-IR, 84% for calretinin-IR and 26% for ChAT-IR neurons in the D group. The spatial density of calbindin-IR neurons, however, did not differ among the three groups. The submucosal neuronal density increased for calbindin-IR, calretinin-IR and ChAT-IR neurons. The average size of neurons in the myenteric plexus neurons in the D group was less than that in the controls and, in the re-fed rats; there was a 34% reduction in size only for the calretinin-IR neurons.
This work demonstrates that expression of the P2X(2) receptor is present in inhibitory, intrinsic primary afferent, cholinergic secretomotor and vasomotor neurons. Undernutrition affected P2X(2) receptor expression in the submucosal plexus, and neuronal and size. These changes were rescued in the re-fed rats.
研究营养不良和再喂养对大鼠回肠神经元 P2X（2）受体、一氧化氮合酶（NOS）、钙视网膜蛋白、钙结合蛋白和胆碱乙酰转移酶（ChAT）的影响。
我们分析了 P2X（2）-表达神经元与 NOS-免疫反应性（IR）、钙结合蛋白-IR、ChAT-IR 和钙视网膜蛋白-IR 神经元在肌间和黏膜下神经丛中的共定位、数量和大小。实验组包括：（1）在整个孕期和产后 42 天维持正常喂养的大鼠（N）；（2）整个孕期和产后 42 天剥夺蛋白质的大鼠（D）；（3）产后 21 天营养不良，然后从第 22 天到第 42 天给予蛋白质饮食的大鼠（DR）。通过免疫组织化学方法对 P2X（2）受体、NOS、ChAT、钙结合蛋白和钙视网膜蛋白进行双重标记，评估肌间和黏膜下神经丛。
我们发现 N、D 和 DR 组的肌间和黏膜下神经元的 P2X（2）受体免疫反应性在细胞质和表面膜中相似。肌间神经丛的双重标记显示，所有组中约 100%的 NOS-IR、钙结合蛋白-IR、钙视网膜蛋白-IR 和 ChAT-IR 神经元也表达 P2X（2）受体。在黏膜下神经丛中，钙视网膜蛋白-IR、ChAT-IR 和钙结合蛋白-IR 神经元几乎都对 P2X（2）受体呈免疫反应性。在肌间神经丛中，D 组 P2X（2）受体-IR 神经元、NOS-IR 神经元、钙视网膜蛋白-IR 神经元和 ChAT-IR 神经元的数量分别增加了 19%、64%、84%和 26%。然而，三组之间钙结合蛋白-IR 神经元的空间密度没有差异。黏膜下神经元密度增加了钙结合蛋白-IR、钙视网膜蛋白-IR 和 ChAT-IR 神经元。D 组肌间神经丛神经元的平均大小小于对照组，而在再喂养大鼠中，仅钙视网膜蛋白-IR 神经元的大小减少了 34%。
本研究表明，P2X（2）受体的表达存在于抑制性、内源性初级传入、胆碱能分泌运动和血管运动神经元中。营养不良影响黏膜下神经丛中 P2X（2）受体的表达、神经元数量和大小。这些变化在再喂养大鼠中得到了挽救。
