Greif K F, Flaherty K N
Department of Biology, Bryn Mawr College, PA 19010.
Neurobiol Aging. 1989 Jan-Feb;10(1):51-4. doi: 10.1016/s0197-4580(89)80010-7.
The effects of altering synaptic activity of sympathetic neurons on the expression of a synaptic vesicle protein (p65) were studied by deafferentation of the superior cervical ganglion (SCG) in adult and aged Fischer-344 rats. Levels of p65, an integral membrane protein of synaptic vesicles, were assayed by radioimmunoassay. After deafferentation, a transient increase in p65 levels is observed in the SCG of adult rats. In aged animals, the response to deafferentation is delayed and enhanced, and levels do not drop to values observed in operated adults. After SCG deafferentation, p65 levels in the iris, an SCG target, initially are depressed below control levels; p65 levels return to control values in adult animals after 14 days, but remain depressed in aged animals. In contrast, a transient increase in p65 levels is observed in the pineal of both adult and aged animals. These results suggest that while the aged sympathetic nervous system retains the ability to respond to alterations in synaptic activity, it is unable to reregulate once a response is initiated.
通过切断成年和老年Fischer-344大鼠颈上神经节（SCG）的传入神经，研究了改变交感神经元突触活动对突触囊泡蛋白（p65）表达的影响。采用放射免疫分析法测定突触囊泡整合膜蛋白p65的水平。切断传入神经后，成年大鼠的SCG中p65水平出现短暂升高。在老年动物中，对切断传入神经的反应延迟且增强，其水平不会降至手术成年动物中观察到的值。切断SCG传入神经后，SCG的靶器官虹膜中的p65水平最初低于对照水平；成年动物的p65水平在14天后恢复到对照值，但老年动物的p65水平仍低于对照值。相反，成年和老年动物的松果体中p65水平均出现短暂升高。这些结果表明，虽然老年交感神经系统保留了对突触活动变化作出反应的能力，但一旦启动反应就无法重新调节。
