甘珀酸对内脏痛大鼠延髓星形胶质细胞和神经元反应的影响

目的:研究侧脑室注射甘珀酸后对福尔马林灌胃致内脏疼痛大鼠的延髓迷走孤束复合体内星形胶质细胞和神经元反应的影响.方法:经侧脑室注射缝隙连接阻断剂甘珀酸(carbenoxolone,CBX)后向大鼠胃内灌入2.5%福尔马林2ml诱发内脏疼痛,用免疫组织化学方法观察延髓迷走孤束复合体(VSC)内抗Fos蛋白(标记神经元)和抗胶质原纤维酸性蛋白(标记星形胶质细胞)的单一或双重标记的免疫荧光染色.结果:福尔马林灌胃后大鼠出现烦躁易激惹,呼吸变快,持续1h;而预先侧脑室注射CBX则动物疼痛行为学反应明显减轻.免疫组织化学染色发现福尔马林灌胃后大鼠VSC中的Fos免疫反应数目增强;大鼠预先侧脑室注射CBX后VSC中的Fos免疫反应数目明显减弱.结论:延髓VSC中的星形胶质细胞和神经元参与福尔马林灌胃致内脏痛的调节,星形胶质细胞可能通过缝隙连接影响神经元对内脏痛的调节功能.

Effects of response of medullary astrocytes and neurons to visceral pain stimulation rats by carbenoxolone

To investigate the effect of carbenoxolone (CBX) intracerebroventricular injection (i.c) on the response of astrocytes and neurons in dorsal vagal-solitary complex (DVC) of visceral pain model rats by formalin gastric injection. Methods: After administration of CBX, a gap junction blocker, and gastric injection 2.5 % formalin, double immunofluorescent methods were used to visualize Fos and glial fibrillary acidic protein (GFAP) immunoreactivity in DVC. Results: After formalin injection, animals appeared restless and agitation, their breathy frequency increased in 60min. Pretreatment with CBX, animal's behavior and breathy frequency reduced. Fos-positive neurons and GFAP- positive astrocytes greatly increased in DVC in visceral pain model rats. In visceral pain model rats with CBX (i.c.) pretreatment, the number of Fos- positive neurons were significantly decreased, while the GFAP expression slightly changed. Conclusions: CBX intracerebroventricular administration had antinociception function in visceral pain model rats. Astrocytes and neurons in DVC may play an important role for modulation of visceral pain induced by the gastric injection of formalin. Astrocytes might have affect on neuronal function by gap junction in modulating visceral pain.