Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Hannover, Germany.
Center for Systems Neuroscience (ZSN), Hannover, Germany.
Neurogastroenterol Motil. 2023 Nov;35(11):e14674. doi: 10.1111/nmo.14674. Epub 2023 Sep 13.
Coping with the ingested food, the gastric regions of fundus, corpus, and antrum display different motility patterns. Intrinsic components of such patterns involving mechanosensitive enteric neurons (MEN) have been described in the guinea pig gastric corpus but are poorly understood in the fundus and antrum.
To elucidate mechanosensitive properties of myenteric neurons in the gastric fundus and antrum, membrane potential imaging using Di-8-ANEPPS was applied. A small-volume injection led to neuronal compression. We analyzed the number of MEN and their firing frequency in addition to the involvement of selected mechanoreceptors. To characterize the neurochemical phenotype of MEN, we performed immunohistochemistry.
In the gastric fundus, 16% of the neurons reproducibly responded to mechanical stimulation and thus were MEN. Of those, 83% were cholinergic and 19% nitrergic. In the antrum, 6% of the neurons responded to the compression stimulus, equally distributed among cholinergic and nitrergic MEN. Defunctionalizing the sensory extrinsic afferents led to a significant drop in the number of MEN in both regions.
We provided evidence for MEN in the gastric fundus and antrum and further investigated mechanoreceptors. However, the proportions of the chemical phenotypes of the MEN differed significantly between both regions. Further investigations of synaptic connections of MEN are crucial to understand the hardwired neuronal circuits in the stomach.
为了应对摄入的食物，胃底、胃体和胃窦区域表现出不同的运动模式。在豚鼠胃体中已经描述了涉及机械敏感肠神经元（MEN）的这种模式的内在成分，但在胃底和胃窦中了解甚少。
为了阐明胃底和胃窦内肌间神经元的机械敏感特性，使用 Di-8-ANEPPS 进行了膜电位成像。小体积注射导致神经元压缩。我们分析了 MEN 的数量及其放电频率，以及选定的机械感受器的参与情况。为了表征 MEN 的神经化学表型，我们进行了免疫组织化学。
在胃底，16%的神经元可重复地对机械刺激作出反应，因此是 MEN。其中，83%是胆碱能的，19%是氮能的。在胃窦，6%的神经元对压缩刺激作出反应，胆碱能和氮能 MEN 各占一半。感觉外传入神经功能丧失导致两个区域的 MEN 数量显著下降。
我们为胃底和胃窦中的 MEN 提供了证据，并进一步研究了机械感受器。然而，这两个区域 MEN 的化学表型比例有显著差异。进一步研究 MEN 的突触连接对于理解胃中的硬性神经元回路至关重要。
