Facial injections of pruritogens or algogens elicit distinct behavior responses in rats and excite overlapping populations of primary sensory and trigeminal subnucleus caudalis neurons
Facial injections of pruritogens or algogens elicit distinct behavior responses in rats and excite overlapping populations of primary sensory and trigeminal subnucleus caudalis neurons
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DOI：
10.1152/jn.00302.2011
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发表时间：
2011-09-01
影响因子：
2.5
通讯作者：
Carstens, E.
中科院分区：
文献类型：
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作者：
Klein, Amanda;Carstens, Mirela Iodi;Carstens, E.
Klein A、Carstens MI、Carstens E。面部注射瘙痒剂或致痛剂可引起大鼠不同的行为反应，并激发初级感觉和三叉神经亚核尾神经元的重叠群体。 《神经生理学杂志》106：1078-1088，2011 年。首次发表于 2011 年 6 月 8 日； doi:10.1152/jn.00302.2011.-在本研究中，我们研究了皮内注射瘙痒剂或海藻剂是否会在 Sprague-Dawley 大鼠中差异性地引起后肢抓伤或前肢擦拭，正如最近在小鼠中报道的那样。我们还研究了初级感觉三叉神经节（TG）和背根神经节（DRG）细胞以及三叉神经尾亚核（Vc）中的二级神经元对瘙痒和痛觉刺激的反应。 5-HT 是最有效的化学物质，可引发针对脸颊的剂量依赖性后肢抓挠，前肢擦拭明显减少，与瘙痒一致。氯喹也会引起明显的抓伤，但不会擦拭。异硫氰酸烯丙酯（AITC；芥子油）引起剂量依赖性擦拭，且没有明显的划痕。辣椒素引起的抓挠和擦拭次数相当，表明有瘙痒和疼痛的混合感觉。通过钙成像，类似于 6% 的培养 TG 和 DRG 细胞对 5-HT 产生反应。大多数 5-HT 敏感细胞也对氯喹、AITC 和/或辣椒素有反应，三分之一对组胺有反应。使用化学搜索策略，我们确定了 Vc 中对皮内注射 5-HT 做出反应的单个单元。大多数是宽动态范围（WDR）或伤害感受特异性（NS），还有一些是机械不敏感的。绝大多数人还对 AITC 和/或辣椒素有反应，因此对瘙痒原没有选择性。这些结果表明，对瘙痒原和致痛原做出反应的初级和二级神经元可能利用群体编码机制来区分瘙痒和疼痛，这些感觉通过不同的后肢抓挠和前肢擦拭反应在行为上表现出来。
Klein A, Carstens MI, Carstens E. Facial injections of pruritogens or algogens elicit distinct behavior responses in rats and excite overlapping populations of primary sensory and trigeminal subnucleus caudalis neurons. J Neurophysiol 106: 1078-1088, 2011. First published June 8, 2011; doi:10.1152/jn.00302.2011.-In the present study, we investigated whether intradermal cheek injection of pruritogens or algogens differentially elicits hindlimb scratches or forelimb wipes in Sprague-Dawley rats, as recently reported in mice. We also investigated responses of primary sensory trigeminal ganglion (TG) and dorsal root ganglion (DRG) cells, as well as second-order neurons in trigeminal subnucleus caudalis (Vc), to pruritic and algesic stimuli. 5-HT was the most effective chemical to elicit dose-dependent bouts of hindlimb scratches directed to the cheek, with significantly less forelimb wiping, consistent with itch. Chloroquine also elicited significant scratching but not wiping. Allyl isothiocyanate (AITC; mustard oil) elicited dose-dependent wiping with no significant scratching. Capsaicin elicited equivalent numbers of scratch bouts and wipes, suggesting a mixed itch and pain sensation. By calcium imaging, similar to 6% of cultured TG and DRG cells responded to 5-HT. The majority of 5-HT-sensitive cells also responded to chloroquine, AITC, and/or capsaicin, and one-third responded to histamine. Using a chemical search strategy, we identified single units in Vc that responded to intradermal cheek injection of 5-HT. Most were wide dynamic range (WDR) or nociceptive specific (NS), and a few were mechanically insensitive. The large majority additionally responded to AITC and/or capsaicin and thus were not pruritogen selective. These results suggest that primary and second-order neurons responsive to pruritogens and algogens may utilize a population coding mechanism to distinguish between itch and pain, sensations that are behaviorally manifested by distinct hindlimb scratching and forelimb wiping responses.