Early Dysfunction of Islet Nerves in Type 1 Diabetes

描述（由申请人提供）：我们对非糖尿病动物的十年研究 和人类的研究表明，胰高血糖素对胰岛素诱导的低血糖的反应， (IIH)都是通过药物介导的由于这种特异性胰高血糖素反应丧失， 在1型糖尿病的早期，早期自主神经缺陷可能是原因。我们 最近的初步数据表明，早期，明显和选择性的损害， BB糖尿病大鼠胰岛交感神经末梢。因此，我们的第一个 具体的目的是将该神经末梢的时间过程和幅度联系起来 BB糖尿病大鼠中受损胰高血糖素反应的损害。交感胰岛 神经末梢将通过双重免疫组织化学观察囊泡 单胺转运蛋白2（VMAT 2）和胰高血糖素。第二个具体目标是 通过阻止神经末梢，防止胰高血糖素对IIH的反应丧失 损伤使用神经生长因子（NOF）治疗BB大鼠发病前， 他们的糖尿病我们的第三个具体目标是复制胰高血糖素的损失 通过神经刺激和免疫抑制的组合， 6-羟基多巴胺（6-OHDA）诱导的终末损伤和胰岛B细胞丢失 链脲佐菌素（STZ）诱导的。 由于神经末梢损伤损害神经元细胞体的反应性， 对于激活，我们的第四个具体目标是确定其大小 BB糖尿病大鼠的反应性受损及其对 胰高血糖素对IIH的反应。这些神经元的反应将通过 包括那些表达核Fos的细胞因此，腹腔神经节（CG）Fos 将在阻断IIH之前和期间评估表达。 在BB糖尿病的第一周和用全身性或全身性 通过病毒转染诱导的NGF或神经节NGF。 最后的具体目标是确定神经末梢的贡献 损伤，胰岛B细胞损失和神经节神经生长因子的损失， 响应能力。因此，糖尿病抗性BB大鼠将接受以下组合： 6-将测量OHDA和STZ以及CG Fos对夹紧IIH的响应。 最后，在本实验中通过ELISA测量神经节的NGF水平， 以前的实验直接将它们与受损的反应性联系起来。 这些实验将共同确定 （神经末梢或细胞体）的胰岛交感神经功能障碍的BB 糖尿病大鼠及其对胰高血糖素对IIH的反应丧失的贡献。

DESCRIPTION (provided by applicant): Our ten-year study of nondiabetic animals and humans shows that the glucagon response to insulin-induced hypoglycemia (IIH) is autonomically mediated. Since this specific glucagon response is lost early in type 1 diabetes, an early autonomic defect may be responsible. Our recent preliminary data demonstrate an early, marked and selective damage to islet sympathetic nerve terminals in BB diabetic rats. Therefore, our first specific aim is to relate the time course and magnitude of this nerve terminal damage to impaired glucagon responses in BB diabetic rats. Islet sympathetic nerve terminals will be visualized by dual immunohistochemistry for vesicular monoamine transporter 2 (VMAT2) and glucagon. Our second specific aim is to prevent the loss of the glucagon response to IIH by preventing nerve terminal damage using nerve growth factor (NOF) to treat BB rats before the onset of their diabetes. Our third specific aim is to reproduce the loss of the glucagon response to IIH in diabetes resistant BB rats by a combination of nerve terminal damage induced by 6-hydroxydopamine (6-OHDA) and islet B-cell loss induced by streptozotocin(STZ). Since nerve terminal damage impairs the responsiveness of neuronal cell bodies to activation, our fourth specific aim is to determine the magnitude of this impaired responsiveness in BB diabetic rats and its contribution to the loss of the glucagon response to IIH. The response of these neurons will be assessed by counting those that express nuclear Fos. Thus, celiac ganglia (CG) Fos expression will be assessed in response to clamped IIH before and during the first week of BB diabetes and in diabetic rats pretreated with either systemic NGF or ganglionic NGF induced by viral transfection. The final specific aim is to determine the contributions of nerve terminal damage, islet B-cell loss and loss of ganglionic NGF to this impaired responsiveness. Thus, diabetes resistant BB rats will receive a combination of 6-OHDA and STZ and the CG Fos responses to clamped IIH will be measured. Finally, ganglionic levels of NGF will be measured by ELISA in this and previous experiments to directly relate them to the impaired responsiveness. Together these experiments will determine the timing, magnitude and location (nerve terminals or cell bodies) of islet sympathetic dysfunction in BB diabetic rats and its contribution to the loss of the glucagon response to IIH.