制約恐懼對老鼠痛覺過敏反應的影響

EFFECT OF CONDITIONED FEAR ON RESPONSIVENESS TO YPERALGESIA IN RATS

本實驗研究之目的在於驗證制約恐懼（conditioned fear）對老鼠痛覺過敏（hyperalgesia）反應的影響。過去的研究發現，老鼠在制約恐懼情境下的痛覺反應並不一致，有趨向兩極的痛覺反應傾 向：其一是「痛覺喪失」（analgesia），其二是「痛覺過敏」。本實驗研究中以老鼠尾部反彈反射（tai-flick rdflexes）的潛伏期（latencies）設定為測量痛覺反應之指標，假設經由制約恐懼的引發，會產生心因性的痛覺過敏反應，而非痛覺喪失。實驗 分成三個階段進行：持握（handing）、恐懼制約（fear congitionong）與測試處理（testing）。持握階段係將老鼠把持於手掌，期使熟悉人手之持握。在恐懼制約階段，實驗組（N＝11）與控制 組（N＝11）均接受等量的電擊處置。尾部反彈反射之實驗處理階段，實驗組接受制約恐懼的實驗處理，控制組則無。結果顯示實驗組較控制組有較短的尾部反彈 潛伏期（P＜0.1），顯示出痛覺過敏的反應。對於本研究與其他實驗在研究方法、過程與結果的差異，均予檢驗與討論。

A number of recent research studies have suggested that the response of pain to electric shock can be conditioned. However， mixed results stemmed from these studies producing either conditioned analgesia (insensitivity to pain) or hyperalgesia when triggered by various conditioned stimuli. The present study hypothesized that psychogenic hyperalgesia can be triggered by conditioned fear as measured by tailflick latencies. In the present experiment， rats (N=22) were exposed to shock an equal number of times in conditioning sessions. Separate groups were then tested either with or without a conditioned fear stimulus (CS) in a tail-flick test. The hypothesis was supported. It was found that a fear CS appeared to produce significantly (p