cAMP反应元件结合蛋白(CREB)在单眼剥夺弱视大鼠视皮层中的表达研究

目前已对突触可塑性的基本特性有了相当程度的认识 ,但对其发育中神经元可塑性的内在分子机制尚待进一步阐明。不少研究提示 ,c AMP反应元件结合蛋白 ( CREB)在学习、记忆和长时程增强 ( LTP)过程中参与长时程突触的可塑性调节 ,推测其在视觉系统可塑性中也发挥着重要作用。本研究通过建立幼年大鼠单眼剥夺弱视模型 ,应用免疫组织化学方法 ,对视觉发育关键期末 ( P45 )大鼠和成年 ( P90 )大鼠视皮层中 CREB和 p CREB的免疫反应性进行观察、比较和分析。结果 :视觉发育关键期内进行单眼视觉剥夺对大鼠视皮层内总 CREB的蛋白表达没有产生显著影响 ,而 p CREB在 P45大鼠的剥夺眼对侧视皮层单眼反应区的 / 、 层中的蛋白表达较剥夺眼同侧视皮层的相应区域弱 ,该差异在该年龄大鼠的双眼反应区及成年后大鼠视皮层内不存在。结论 :CREB可能通过该磷酸化形式在视觉系统可塑性中发挥作用

INVESTIGATION OF CYCLIC AMP RESPONSE ELEMENT BINDING PROTEIN (CREB) EXPRESSION IN THE VISUAL CORTEX OF MONOCULARLY DEPRIVED RATS

At present, the characteristics of synaptic plasticity have been known to a great extent, but the potential molecular mechanisms underlying this developmental neuronal plasticity remain to be clarified. A series of studies have suggested that cyclic AMP response element binding protein (CREB) is involved in the regulation of long-term synaptic plasticity in the course of learning, memory and long-term potentiation. We hypothesized that CREB will play an important role in the plasticity of visual system. The total CREB and phosphorylated CREB immunoreactivity in the visual cortex of monocularly deprived rats at various ages, ie, postnatal day 45 and postnatal day 90, were studied. Immunohistochemical analyses with anti-CREB and anti-phosphorylated CREB polycloned antibodies were performed on tissue sections obtained from the monocularly deprived rats and normal control ones. We found that monocular deprivation in the critical period had little effect on total CREB expression in the rat visual cortex. However, monocular deprivation determines a decrease of phosphorylated CREB immunoreactivity exclusively in the monocular segment (OC1M) area of the visual cortex contralateral to the deprived eye at postnatal day 45, especially in layers Ⅱ/Ⅲ and Ⅳ. No significant visual deprivation effect on phosphorylated CREB expression was seen in the binocular segment (OC1B) area at the same age or in the visual cortex at postnatal day 90. Our results indicate that CREB may play roles in the plasticity of visual system through its phosphorylated state.