The role of neuropeptides on ocular physiology and pathophysiology

1. 采用间接免疫荧光法和放射免疫分析法（RIA）研究了急性疱疹性角膜炎小鼠眼感觉神经候选神经递质之一P物质（SP）的序列变化。在角膜中，SP免疫反应性仅在感染后第2天疱疹灶处略有下降，在感染后第4天整个角膜中未见SP阳性纤维。然而，在三叉神经节（TG）中，即使感染后SP免疫反应神经细胞和纤维也未发生变化。RIA研究显示，角膜中SP的含量在第4天急剧减少，感染小鼠TG中SP的含量几乎与对照组相同。我们还研究了神经肽对家兔眼循环的影响。静脉注射血管活性肠多肽（VIP）可增加眼内血容量（BV）和眼内压（IOP），降低全身血压（BP）。静脉注射NPY后，观察到BV和IOP降低，BP升高。SP对这些参数都没有影响。这些结果表明NPY在青光眼治疗中的潜在作用。虽然许多神经肽在视网膜中已被免疫组织化学鉴定，但其生理作用仍不清楚。我们评估了这些神经肽如何影响小鸡视网膜在体内不同发育阶段的ERG。卵孵化初期，卵孔内注射VIP可观察到卵孔内振荡电位（OP1和OP2）的变化，而注射其他肽对卵孔内振荡电位无明显影响。这些观察结果表明VIP对视网膜突触回路具有调节作用，特别是在发育过程中。

1. We investigated the sequential changes of substance P (SP), one of the neurotransmitter candidates of ocular sensory nerves, in acute herpetic keratitis of mice using indirect immunofluorescence method and radioimmunoassey (RIA). In cornea, the SP immunoreactivity was slightly reduced only at herpetic focus on the 2nd day post-infection (PI), and no SP positive fibers were visualized in whole cornea on 4th day PI. In trigeminal ganglia (TG), however, no change was observed in SP immunoreactive nerve cells and fibers even after infection. RIA studies revealed that the amount of SP in cornea was dramatically reduced on 4th day PI, and that TG of infected mice contained almost as much amount of SP as those of controls did at the time examined.2. We also investigated the effects of neuropeptides on ocular circulation of rabbit. Vasoactive intestinal polypeptide (VIP), when injected i.v., increased the blood volume in the eye (BV) and intraocular pressure (IOP), and decreased systemic blood pressure (BP). When NPY was injected i.v., the reduction of BV and IOP, and the rise of BP were observed. SP had no effect on any of those parameters. These results indicate the potential usefulness of NPY on glaucoma therapy.3. Although many neuropeptides have been immunohistochemically identified in retina, their physiological roles are still unclear. We evaluated how those neuropeptides might affect ERG of chick retina, in vivo at various stages of development. The alternation of oscillatory potentials ( OP1 and OP2 ) were observed after intracameral injection of VIP especially at early stages after hatching, while no effect on oscillatory potentials was detected after injection of any other peptides tested. These observation suggests that VIP has modulatory effects on the synaptic circuits in the retina particularly during developments.