Mech-Sense, Department of Gastroenterology, Aalborg Hospital, Denmark.
Eur J Pain. 2010 Mar;14(3):273-81. doi: 10.1016/j.ejpain.2009.05.013. Epub 2009 Jun 21.
Visceral afferents originating from different gut-segments converge at the spinal level. We hypothesized that chemically-induced hyperalgesia in the oesophagus could provoke widespread visceral hypersensitivity and also influence descending modulatory pain pathways. Fifteen healthy volunteers were studied at baseline, 30, 60 and 90 min after randomized perfusion of the distal oesophagus with either saline or 180 ml 0.1M HCl+2mg capsaicin. Electro-stimulation of the oesophagus, 8 cm proximal to the perfusion site, rectosigmoid electrical stimulation and rectal mechanical and heat stimulations were used. Evoked brain potentials were recorded after electrical stimulations before and after oesophageal perfusion. After the perfusion, rectal hyperalgesia to heat (P<0.01, 37%) and mechanical (P=0.01, 11%) stimulations were demonstrated. In contrast, hypoalgesia to electro-stimulation was observed in both the oesophagus (P<0.03, 23%) and the sigmoid colon (P<0.001, 18%). Referred pain areas to electro-stimulation in oesophagus were reduced by 13% after perfusion (P=0.01). Evoked brain potentials to rectosigmoid stimulations showed decreased latencies and amplitudes of P1, N1 and P2 (P<0.05), whereas oesophagus-evoked brain potentials were unaffected after perfusion. In conclusion, modality-specific hyperalgesia was demonstrated in the lower gut following chemical sensitization of the oesophagus, reflecting widespread central hyperexcitability. Conversely, hypoalgesia to electrical stimulation, decreases in referred pain and latencies of evoked brain potentials was seen. This outcome may reflect a counterbalancing activation of descending inhibitory pathways. As these findings are also seen in the clinical setting, the model may be usable for future basic and pharmacological studies.
内脏传入纤维起源于不同的肠道节段,在脊髓水平汇聚。我们假设食管化学性超敏反应可能引发广泛的内脏高敏反应,并影响下行调制疼痛通路。15 名健康志愿者在基线时、随机灌注远端食管生理盐水或 0.1M HCl+2mg 辣椒素 180ml 后 30、60 和 90 分钟进行研究。在灌注部位近端 8cm 的食管进行电刺激、直肠直肠电刺激和直肠机械和热刺激。在食管灌注前后进行电刺激记录诱发的脑电位。灌注后,直肠对热(P<0.01,37%)和机械(P=0.01,11%)刺激的痛觉过敏。相比之下,食管(P<0.03,23%)和乙状结肠(P<0.001,18%)的电刺激痛觉减退。灌注后,电刺激引起的食管牵涉痛面积减少 13%(P=0.01)。直肠乙状结肠刺激诱发的脑电位潜伏期和 P1、N1 和 P2 的振幅降低(P<0.05),而灌注后食管诱发的脑电位不受影响。结论:食管化学敏化后,下消化道出现特定模式的痛觉过敏,反映出广泛的中枢过度兴奋。相反,电刺激的痛觉减退、牵涉痛和诱发脑电位潜伏期的减少。这种结果可能反映了下行抑制通路的平衡激活。由于这些发现也见于临床,该模型可能可用于未来的基础和药理学研究。