McMahon Stephen B, Abel Caroline
Department of Physiology, U.M.D.S., London SE1 7EH U.K.
Pain. 1987 Jan;28(1):109-127. doi: 10.1016/0304-3959(87)91065-7.
Normal healthy visceral tissue is largely insensitive to many kinds of tissue damaging stimuli, such as cutting, crushing or burning. When inflamed, however, visceral tissue frequently and easily elicits pain. Here we have produced inflammatory responses in urinary bladders of chronically decerebrated rats with irritant chemicals, as a model of a visceral pain state. The irritants used were 25% turpentine, 2.5% mustard oil, 2% croton oil. All produced a strong inflammatory response, as judged by protein extravasation and oedema, and invasion of the tissue with leucocytes, which started within hours of treatment. The inflammatory states were associated with hyperexcitable bladder reflexes; baseline pressures were larger at given volumes, and large micturition contractions occurred at lower volumes. These changes persisted for up to 48 h after a single treatment. The behaviour of the animals and their responsiveness to noxious stimulation were also assessed. In general animals were hypersensitive to noxious stimuli applied to the tail or caudal abdomen, with small or no changes in responses to hind limb or rostral abdominal stimulation. These irritants, particularly turpentine, applied to chronic decerebrate rats may thus provide useful models for studies of the neuronal processes which contribute to visceral nociception.
正常健康的内脏组织对多种组织损伤刺激（如切割、挤压或灼烧）大多不敏感。然而，当发炎时，内脏组织常常容易引发疼痛。在此，我们用刺激性化学物质在慢性去大脑大鼠的膀胱中引发炎症反应，以此作为内脏疼痛状态的模型。所用的刺激物为25%的松节油、2.5%的芥子油、2%的巴豆油。根据蛋白质外渗、水肿以及白细胞浸润情况判断，所有刺激物均引发了强烈的炎症反应，这种反应在治疗后数小时内就开始出现。炎症状态与膀胱反射过度兴奋相关；在给定容量下基线压力更高，且在较低容量时就会出现强烈的排尿收缩。单次治疗后，这些变化可持续长达48小时。我们还评估了动物的行为及其对有害刺激的反应性。一般来说，动物对施加于尾巴或尾腹部的有害刺激过敏，而对后肢或头腹部刺激的反应变化很小或没有变化。因此，将这些刺激物，尤其是松节油，应用于慢性去大脑大鼠，可能为研究导致内脏痛觉的神经元过程提供有用的模型。
