Faculty of Health Sciences, Murdoch University, Perth, Western Australia.
Neuroscience. 2011 Feb 23;175:300-14. doi: 10.1016/j.neuroscience.2010.11.064. Epub 2010 Dec 20.
The purpose of this study was to determine whether α(1)-adrenoceptors are expressed on primary nociceptive afferents that innervate healthy skin. Skin and dorsal root ganglia were collected from adult male Wistar rats and assessed using fluorescence immunohistochemistry with antibodies directed against α(1)-adrenoceptors alone or in combination with specific labels including myelin basic protein and neurofilament 200 (markers of myelinated nerve fibres), protein gene product 9.5 (a pan-neuronal marker), tyrosine hydroxylase (sympathetic neurons), isolectin B(4) (IB(4): non-peptidergic sensory neurons), calcitonin gene related peptide (CGRP) and transient receptor potential vanilloid receptor 1 (TRPV1) (peptidergic sensory neurons). Double labelling in dorsal root ganglia confirmed the expression of α(1)-adrenoceptors within sub-populations of CGRP, IB(4) and TRPV1 immunoreactive neurons. Myelinated and unmyelinated sensory nerve fibres in the skin expressed α(1)-adrenoceptors whereas sympathetic nerve fibres did not. The expression of α(1)-adrenoceptors on C- and A-delta nociceptive afferent fibres provides a histochemical substrate for direct excitation of these fibres by adrenergic agonists. This may help to explain the mechanism of sensory-sympathetic coupling that sometimes develops on surviving primary nociceptive afferents in neuropathic pain states.
本研究旨在确定α(1)-肾上腺素受体是否存在于支配健康皮肤的初级伤害感受传入纤维上。从成年雄性 Wistar 大鼠中收集皮肤和背根神经节，并使用荧光免疫组织化学技术，单独或与针对α(1)-肾上腺素受体的抗体结合使用，与特定标记物（包括髓鞘碱性蛋白和神经丝 200（有髓神经纤维的标志物）、蛋白基因产物 9.5（泛神经元标志物）、酪氨酸羟化酶（交感神经元）、IB(4)（非肽能感觉神经元）、降钙素基因相关肽 (CGRP) 和瞬时受体电位香草酸受体 1 (TRPV1)（肽能感觉神经元））进行联合评估。背根神经节的双重标记证实了α(1)-肾上腺素受体在 CGRP、IB(4)和 TRPV1 免疫反应性神经元的亚群中表达。皮肤中的有髓和无髓感觉神经纤维表达α(1)-肾上腺素受体，而交感神经纤维则不表达。C 和 Aδ伤害感受传入纤维上α(1)-肾上腺素受体的表达为肾上腺素能激动剂直接兴奋这些纤维提供了组织化学基础。这有助于解释神经病理性疼痛状态下存活的初级伤害感受传入纤维上有时发生的感觉-交感耦合机制。
