INTESTINAL FUNCTION IN A HIBERNATOR: ADAPTIVE CHANGES

冬眠者的肠黏膜似乎能维持 直到春季出现的吸收能力，尽管缺乏 冬眠期间的瘤胃营养。相比之下，在非 冬眠的哺乳动物导致显著减少 3天后恢复吸收功能。这个项目的目的是 确定肠道营养和营养成分的季节变化 电解液的运输发生在年循环期间 冬眠地松鼠，并确定其机制和 导致肠道运输适应性调节的信号 在一年一度的周期中发挥作用。肠糖和电解质 春季将对地松鼠的运输进行评估， 夏天、秋天和冬天。冬季学习将涉及冬眠 松鼠以及被允许保持活动的松鼠 在温暖的房间里进食。跨血管内皮细胞葡萄糖流量， 将在空肠段中测量钠和氯化物 改进型Ussing-型燃烧室。葡萄糖跨过刷子流入 将测量边界膜以确定是否在 葡萄糖载体的数量或葡萄糖对其亲和力 承运商要对运输功能的适应性变化负责。 每组松鼠的肠道质量和结构将 通过测量重量、蛋白质和DNA含量来估计， 以及绒毛和隐窝大小的粘膜 与生理实验中使用的节段相邻的节段。 血液和组织样本将从用于 用于稍后分析多肽和其他物质的传输实验 可能与季节变化有关的信使 肠道结构和功能。药理和 组织学工具将被用来识别中介信号 肠神经刺激引起的粘膜反应。这些研究 预计将提供对自然节奏的洞察 胃肠道和导致适应性的信号 冬眠期间的调节。

The intestinal mucosa of the hibernator appears to maintain absorptive capacity until spring emergence despite the lack of luminal nutrition during hibernation. In contrast, fasting in non- hibernating mammals results in a significant reduction in absorptive function after 3 days. The aims of this project are to determine if seasonal variations in intestinal nutrient and electrolyte transport occur during the annual cycle for the hibernating ground squirrel, and to identify the mechanisms and signals that lead to adaptive regulation of intestinal transport function during the annual cycle. Intestinal sugar and electrolyte transport will be assessed in ground squirrels during the spring, summer, fall and winter. Winter studies will involve hibernating squirrels as well as squirrels that were allowed to remain active and feeding in a warm room. Transepithelial fluxes of glucose, sodium and chloride will be measured in jejunal segments set up in modified Ussing-type chambers. Glucose influx across the brush border membrane will be measured to determine if changes in the number of glucose carrier sites or the affinity of glucose for its carrier are responsible for adaptive changes in transport function. Intestinal mass and structure in each group of squirrels will be estimated by measuring the weights, protein and DNA content, and villus and crypt dimensions of mucosa harvested from segments adjacent to those used in the physiological experiments. Blood and tissue samples will be collected from squirrels used in the transport experiments for later analysis of peptides and other messengers that might be involved in seasonal changes in intestinal structure and function. Pharmacological and histological tools will be used to identify the signals that mediate the mucosal response to enteric neural stimulation. These studies are expected to provide insight into the natural rhythms of the gastrointestinal tract and the signals that lead to adaptive regulation during hibernation.