Shimizu T, Izumi K, Fujita S, Koja T, Sorimachi M, Ohba N, Fukuda T
Department of Pharmacology, Faculty of Medicine, Kagoshima University, Japan.
J Pharmacol Exp Ther. 1987 Nov;243(2):690-5.
Effects of chemical sympathectomy on corneal changes induced in mice by a s.c. injection of capsaicin were investigated. Pretreatment with a s.c. injection of 6-hydroxydopamine (6-OHDA) on the 1st and 2nd postnatal day or on the 14th and 15th postnatal day led to a marked suppression of the capsaicin-induced corneal lesions. This suppressive effect also was evident in case of administration after capsaicin treatment. Intraventricular injection of 6-OHDA had a slight, transient effect. DSP4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine], another potent substance used for sympathetic denervation, had a suppressive effect similar to that of 6-OHDA. The concentration of capsaicin in tissues of the head was unaltered with 6-OHDA. The content of substance P (SP) in the ocular anterior segments was decreased, dose-dependently, with capsaicin administration. Neonatal administration of 6-OHDA decreased the rate of capsaicin-induced reduction of SP. However, this effect of 6-OHDA was too slight to explain the suppression of the corneal lesions, as the intensity score of lesions with a large dose of capsaicin after 6-OHDA was lower than that with a small dose of capsaicin without 6-OHDA, whereas SP content in the former was still much lower than that in the latter. On the other hand, the content of norepinephrine in the ocular tissues was decreased in the presence of 6-OHDA but not capsaicin. These results suggest that the corneal changes induced by capsaicin are largely inhibited by a decreased activity in the peripheral sympathetic system.
研究了化学性交感神经切除术对皮下注射辣椒素诱导的小鼠角膜变化的影响。在出生后第1天和第2天或出生后第14天和第15天皮下注射6-羟基多巴胺（6-OHDA）进行预处理，可显著抑制辣椒素诱导的角膜损伤。在辣椒素治疗后给药的情况下，这种抑制作用也很明显。脑室内注射6-OHDA有轻微的、短暂的作用。DSP4 [N-(2-氯乙基)-N-乙基-2-溴苄胺]，另一种用于交感神经去支配的有效物质，具有与6-OHDA相似的抑制作用。6-OHDA处理后，头部组织中辣椒素的浓度未改变。随着辣椒素的给药，眼前节中P物质（SP）的含量呈剂量依赖性降低。新生小鼠给予6-OHDA可降低辣椒素诱导的SP减少率。然而，6-OHDA的这种作用太轻微，无法解释角膜损伤的抑制作用，因为6-OHDA后大剂量辣椒素引起的损伤强度评分低于无6-OHDA时小剂量辣椒素引起的损伤强度评分，而前者的SP含量仍远低于后者。另一方面，在存在6-OHDA的情况下，眼组织中去甲肾上腺素的含量降低，但辣椒素处理后未降低。这些结果表明，辣椒素诱导的角膜变化在很大程度上受到外周交感神经系统活性降低的抑制。
