Bynke G, Håkanson R, Sundler F
Eur J Pharmacol. 1984 Jun 1;101(3-4):253-8. doi: 10.1016/0014-2999(84)90165-1.
Substance P (SP)-containing nerve fibers are few in the rabbit cornea, which is richly supplied with acetylcholinesterase-positive nerve fibers, presumably sensory in nature. Treatment with capsaicin given by retrobulbar injection 48 h prior to sacrifice caused SP to disappear from the SP nerves in the cornea without affecting the acetylcholinesterase-positive nerve fibers. The corneal sensitivity to a tactile stimulus (wetted cotton swabs) and to a chemical stimulus (local application of capsaicin) and the disruption of the blood-aqueous barrier after local injury (infrared irradiation of the iris) were tested after pretreatment with capsaicin (retrobulbar injection) the SP antagonist [D-Pro2,D-Trp7,9]SP (single topical application or long-term application twice daily for 2 months), the local anaesthetic oxibuprocaine (topical application), or the neuronal blocker tetrodotoxin (intravitreal injection). All these treatments abolished or reduced the disruption of the blood-aqueous barrier after local injury but only oxibuprocaine and tetrodotoxin abolished the corneal sensitivity to tactile and chemical stimuli. It is suggested that SP nerve fibers constitute a minor proportion of the sensory nerve supply to the cornea, that the neurogenic mechanisms involved in the response to ocular injury differ from those involved in corneal nociception, and that uveal SP is involved in the response to ocular trauma and that corneal SP is probably not necessary for corneal nociception.
含P物质（SP）的神经纤维在兔角膜中较少，而兔角膜中富含乙酰胆碱酯酶阳性神经纤维，推测其本质上是感觉神经纤维。在处死前48小时通过球后注射给予辣椒素处理，可使角膜中SP神经纤维中的SP消失，而不影响乙酰胆碱酯酶阳性神经纤维。在用辣椒素（球后注射）、SP拮抗剂[D - Pro2，D - Trp7,9]SP（单次局部应用或每日两次长期应用2个月）、局部麻醉药奥布卡因（局部应用）或神经元阻滞剂河豚毒素（玻璃体内注射）预处理后，测试角膜对触觉刺激（湿棉签）和化学刺激（局部应用辣椒素）的敏感性以及局部损伤（虹膜红外线照射）后血 - 房水屏障的破坏情况。所有这些处理均消除或减轻了局部损伤后血 - 房水屏障的破坏，但只有奥布卡因和河豚毒素消除了角膜对触觉和化学刺激的敏感性。提示SP神经纤维在角膜感觉神经供应中占较小比例，眼部损伤反应中涉及的神经源性机制与角膜伤害感受中涉及的机制不同，葡萄膜SP参与眼部创伤反应，而角膜SP可能对角膜伤害感受并非必需。
