大白鼠脑与松果体β肾上腺素能受体的老年性变化

The Change on β-adrenergic receptor density in aged rat brain and pineal gland

目的 研究老年大鼠大脑皮质、海马、小脑皮质和松果体β-肾上腺素能受体的变化.方法 选用老年(20个月)和青年(3个月)SD大白鼠,以放射配基受体结合分析法测定大鼠大脑皮质、海马、小脑皮质和松果体β受体密度、比较2个年龄组上述脑区β受体含量变化及松果体β受体日夜周期变化.结果 与青年组比较,老年组大脑皮质、海马β受体含量明显降低(P<0.01),小脑皮质β受体含量变化不明显(P>0.05),松果体β受体含量在青年组白天明显高于夜间,而老年组变化不明显.结论 衰老时大鼠大脑皮质和海马β受体含量减少,松果体β受体含量的日夜周期改变消失.

Objective To study the change of β-adrenergic receptor(β-AR) density in the cerebral cortex, hippocampus,cerebellum and pineal gland in aged rat.Methods Aged rate(20 month)and young rats(3 month)were included in this study,β-AR density in the cerebral cortex,hippocampus,cerebellum and pineal gland was analyzed by radioligand binding assay of receptors. Result The β-AR density in the cerebral cortex, hippocampus had significantly decreased in aged groups compared with young group, but β-AR density in cerebellum didn' t show a significant change between two groups.The β-AR density of pineal gland in young rats had significantly increased in light group(rats were killed on 18.00pm)compared with dark group(rats were killed at 0.00am),butβ-AR density in pineal gland in aged rats hadn't shown a significant change between light group and dark group. Conclusion The experiment showed that in aged rats, β- adrenergic receptor density in both cerebral cortex and hippocampus were decreased and this decreasing change disappeared in the light-dark circadian rhythm in pineal gland.The significance of our results in brain aging and biological rhythm was discussed.