MECHANISMS UNDERLYING THE MONOCULAR DEPRIVATION EFFECT

单眼剥夺效应的机制

• 批准号: 3258521
• 负责人: BARBARA GORDON-LICKEY
• 金额: $ 15.71万
• 依托单位: UNIVERSITY OF OREGON
• 依托单位国家: 美国
• 财政年份: 1982
• 资助国家: 美国
• 起止时间: 1982-07-01 至 1991-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3258521
• 关键词: acetylcholine; axon; binocular vision; cats; electrophysiology; growth /development; high performance liquid chromatography; histology; infant animal; lateral geniculate body; neural plasticity; norepinephrine; visual cortex; visual deprivation; visual perception; visual photosensitivity

The long term objective of this proposal is to elucidate the role of norepinephrine (NE) and beta receptors in visual system plasticity. The experiments are based on the finding that depleting NE with 6- hydroxydopamine (6-OHDA) decreases plasticity in the visual cortex. The first experiments attempt to determine whether NE depletion is sufficient for this effect. They make use of our recent finding that very small amounts of 6-OHDA can deplete NE in the visual cortex. We ask if these small doses of 6-OHDA also cause a decrease in plasticity. High performance liquid chromatography (HPLC) is used to measure NE depletion and plasticity is assayed by recording from area 17 in an animal that has had a week of monocular deprivation beginning at 5-6 weeks of age. If small, but depleting doses of 6-OHDA do not alter plasticity, we will conclude that NE depletion is not sufficient for decreases in plasticity. The next experiments ask whether NE depletion or increased beta receptor binding can better account for changes in plasticity. First, we will measure the time course of NE depletion and beta receptor binding capacity in response to 6-OHDA. Receptor binding will be measured with radioactive beta receptor ligands. Next, we will measure the dose dependence of depletion and receptor binding capacity. We ask whether the time and dose dependence of beta receptor binding better parallels changes in plasticity than does the time and dose dependence of NE depletion. The final experiments examine the role of beta receptors in the termination of the critical period. The development of beta receptors will be studied in normal, dark reared, and binocularly sutured animals. Since dark rearing but not binocular suture postpones the termination of the critical period, we hope to find that dark rearing but not binocular suture postpones the development of beta receptors.

该提案的长期目标是阐明 去甲肾上腺素 (NE) 和 β 受体在视觉系统可塑性中的作用。 这 实验基于以下发现：用 6- 耗尽 NE 羟基多巴胺 (6-OHDA) 会降低视觉皮层的可塑性。 这 第一个实验试图确定 NE 消耗是否足够 为了这个效果。 他们利用了我们最近发现的非常小的 大量的 6-OHDA 会消耗视觉皮层中的 NE。 我们问是否这些 小剂量的6-OHDA也会导致可塑性下降。 高的 使用高效液相色谱 (HPLC) 测量 NE 消耗 可塑性是通过记录动物的 17 区来测定的 从 5-6 周龄开始，进行一周的单眼剥夺。 如果 小但消耗剂量的 6-OHDA 不会改变可塑性，我们将 结论是 NE 消耗不足以降低可塑性。 接下来的实验将询问 NE 是否被耗尽或 β 受体是否增加 结合可以更好地解释可塑性的变化。 首先，我们将 测量 NE 消耗的时间过程和 β 受体结合能力 响应 6-OHDA。 受体结合将用放射性测量 β受体配体。 接下来，我们将测量剂量依赖性 消耗和受体结合能力。 我们询问时间和剂量是否 β受体结合的依赖性更好地平行于可塑性的变化 NE 消耗的时间和剂量依赖性更重要。 最后的实验检查了β受体在终止中的作用 的关键时期。 将研究β受体的发育 在正常、黑暗饲养和双眼缝合的动物中。 天黑以来 饲养但不是双眼缝合推迟了关键的终止 期间，我们希望找到暗饲养而不是双眼缝合 推迟β受体的发育。