Enhanced withdrawal responses to heat and mechanical stimuli following intraplantar injection of capsaicin in rats
Enhanced withdrawal responses to heat and mechanical stimuli following intraplantar injection of capsaicin in rats
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DOI：
10.1016/0304-3959(96)03104-1
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发表时间：
1996-09-01
期刊：
影响因子：
7.4
通讯作者：
Simone, DA
中科院分区：
文献类型：
--
作者：
Gilchrist, HD;Allard, BL;Simone, DA
在足底注射辣椒素之前和之后，测量对施加到大鼠后爪的足底表面的热和机械刺激的撤回反应。在不同的大鼠组中，将1、10和30 μ g的辣椒素剂量和载体以10 μ l的体积给予足底表面的中心。在注射前和注射后从两个后爪获得由辐射热诱发的退缩潜伏期和由机械刺激（von Frey单丝）诱发的退缩频率。对热的痛觉过敏定义为退缩潜伏期的减少，机械性痛觉过敏由退缩反应频率的增加指示。足底注射辣椒素引起的伤害性行为，其特征在于提升和保护注射的爪，其通常在注射后持续长达3分钟。辣椒素产生的撤回潜伏期减少热和机械刺激以剂量依赖性的方式增加撤回的频率。仅在注射的爪上观察到这些作用。辣椒素引起的痛觉过敏持续时间也呈剂量依赖性。辣椒素刺激后45 min内，对热的戒断反应降低，而对机械刺激的戒断反应持续升高至4 h。机械性痛觉过敏的区域包括足底表面的大部分，并且在注射的近端和远端延伸约9mm。注射溶剂不会显著改变对热或机械刺激的戒断反应。这些研究表明，大鼠足底注射辣椒素可产生对热和机械刺激的痛觉过敏。该模型可用于辣椒素诱发痛敏的行为学、生理学和药理学研究。
Withdrawal responses to heat and mechanical stimuli applied to the plantar surface of the rat hindpaw were measured before and after an intraplantar injection of capsaicin. In separate groups of rats, capsaicin doses of 1, 10 and 30 mu g, and the vehicle were given into the center of the plantar surface in a volume of 10 mu l. Withdrawal latency evoked by radiant heat and the frequency of withdrawal evoked by mechanical stimuli (von Frey monofilaments) were obtained from both hindpaws before and after injection. Hyperalgesia to heat was defined as a decrease in withdrawal latency and mechanical hyperalgesia was indicated by an increase in withdrawal response frequency. Intraplantar injection of capsaicin evoked nocifensive behavior characterized by lifting and guarding the injected paw which typically lasted up to 3 min following injection. Capsaicin produced a decrease in withdrawal latency to heat and increased the frequency of withdrawal to mechanical stimuli in a dose-dependent manner. These effects were observed on the injected paw only. The duration of hyperalgesia produced by capsaicin was also dose-dependent. Withdrawal latencies to heat were decreased up to 45 min following capsaicin while withdrawal responses to mechanical stimuli remained elevated up to 4 h. The area of mechanical hyperalgesia included most of the plantar surface and extended approximately 9 mm proximal and distal to the injection. Injection of the vehicle did not significantly alter withdrawal responses to heat or mechanical stimuli. These studies demonstrate that intraplantar injection of capsaicin in rats produces hyperalgesia to heat and mechanical stimuli. This model should be useful for correlative behavioral, physiological and pharmacological studies of underlying mechanisms of capsaicin-evoked hyperalgesia.