De Matteis R, Ricquier D, Cinti S
Institute of Normal Human Morphology-Anatomy, University of Ancona, Italy.
J Neurocytol. 1998 Dec;27(12):877-86. doi: 10.1023/a:1006996922657.
Interscapular brown adipose tissue (IBAT), a site of nonshivering thermogenesis in mammals, is neurally controlled. The co-existence of sympathetic and peptidergic innervation has been demonstrated in different brown adipose depots. We studied the morphological profile of IBAT innervation and tested by immunohistochemical methods whether cold and warm stimulation are accompanied by modifications in the density of parenchymal noradrenergic nerve fibers. We also studied the immunoreactivity of afferent fibers--which contain calcitonin gene-related peptide (CGRP) and substance P (SP)--in different functional conditions. IBAT was obtained from adult rats (6 weeks old) acclimated at different temperatures (4 degrees, 20 degrees, and 28 degrees C). Tissue activity was evaluated by studying the immunolocalization of uncoupling protein (UCP-1), a specific marker of brown adipose tissue. Noradrenergic and peptidergic innervation were seen to arise from morphologically different nerves. Fibers staining for tyrosine hydroxylase (TH) were thin, unmyelinated hilar nerves, and CGRP- and SP-positive fibers were in thick nerves containing both myelinated and unmyelinated fibers. Under cold stimulation, noradrenergic neurons produce greater amounts of TH, and their axons branch, resulting in increased parenchymal nerve fibers density. Neuropeptide Y (NPY) probably co-localizes with TH in noradrenergic neurons, but only in the perivascular nerve fiber network. The parenchymal distribution of NPY to interlobular arterioles and capillaries suggests that this peptide must have other functions besides that of innervating arteriovenous anastomoses, as hypothesized by other researchers. The different distribution of CGRP and SP suggests the existence of different sensory neuronal populations. The detection of CGRP at the parenchymal level is in line with the hypothesis of a trophic action of this peptide.
肩胛间棕色脂肪组织（IBAT）是哺乳动物非寒战产热的部位，受神经控制。在不同的棕色脂肪储存部位已证实存在交感神经和肽能神经支配。我们研究了IBAT神经支配的形态学特征，并通过免疫组织化学方法检测冷刺激和热刺激是否伴随着实质去甲肾上腺素能神经纤维密度的改变。我们还研究了在不同功能状态下传入纤维（含有降钙素基因相关肽（CGRP）和P物质（SP））的免疫反应性。IBAT取自适应于不同温度（4℃、20℃和28℃）的成年大鼠（6周龄）。通过研究解偶联蛋白（UCP-1）的免疫定位来评估组织活性，UCP-1是棕色脂肪组织的特异性标志物。去甲肾上腺素能和肽能神经支配来自形态不同的神经。酪氨酸羟化酶（TH）染色的纤维是细的、无髓鞘的肺门神经，CGRP和SP阳性纤维存在于含有髓鞘和无髓鞘纤维的粗神经中。在冷刺激下，去甲肾上腺素能神经元产生更多的TH，其轴突分支，导致实质神经纤维密度增加。神经肽Y（NPY）可能与去甲肾上腺素能神经元中的TH共定位，但仅在血管周围神经纤维网络中。NPY在小叶间小动脉和毛细血管的实质分布表明，该肽除了如其他研究者所假设的支配动静脉吻合外，必定还有其他功能。CGRP和SP的不同分布表明存在不同的感觉神经元群体。在实质水平检测到CGRP符合该肽具有营养作用的假说。
