Houghton A K, Westlund K N
Department of Anatomy and Neurosciences, University of Texas Medical Branch, Galveston 77555-1069, USA.
Neuroreport. 1996 Jun 17;7(9):1497-501. doi: 10.1097/00001756-199606170-00011.
Descending inhibition is increased after the induction of inflammation of the knee. The present study investigated whether this effect is mediated through alpha 2-adrenoceptors and/or I2 imidazoline receptors in the rat. An alpha 2-adrenoceptor antagonist, RX 821002, a selective I2 imidazoline ligand, RS 45041, and idazoxan, which has affinity for both these receptor types, were administered. After the induction of acute arthritis by intra-articular injection of kaolin and carrageenan, the agents binding to I2 imidazoline receptors further reduced the paw withdrawal latency to radiant heat beyond that induced by acute arthritis, i.e. these drugs were pronociceptive, potentiating hyperalgesia. These results suggest that I2 imidazoline receptors have an important role to play in modulation of hyperalgesia during acute inflammation. Development of I2 imidazoline drugs may prove useful in the treatment of hyperalgesia.
膝关节炎症诱导后下行抑制作用增强。本研究调查了这种效应是否通过大鼠体内的α2-肾上腺素能受体和/或I2咪唑啉受体介导。给予α2-肾上腺素能受体拮抗剂RX 821002、选择性I2咪唑啉配体RS 45041以及对这两种受体类型均有亲和力的咪唑克生。通过关节内注射高岭土和角叉菜胶诱导急性关节炎后，与I2咪唑啉受体结合的药物进一步缩短了对辐射热的爪退缩潜伏期，超过了急性关节炎诱导的水平，即这些药物具有促痛作用，增强了痛觉过敏。这些结果表明，I2咪唑啉受体在急性炎症期间痛觉过敏的调节中起重要作用。开发I2咪唑啉类药物可能被证明对治疗痛觉过敏有用。
