Peretz B, Srivatsan M
Department of Physiology and Biophysics, University of Kentucky Medical Center, Lexington 40536-0084, USA.
Behav Brain Res. 1996 Oct;80(1-2):203-10. doi: 10.1016/0166-4328(96)00037-x.
In the marine mollusc Aplysia, a reduced level of activity of circulating AChE (acetylcholinesterase) signals the onset of aging [28], as it does in mammals [23,25]. In old Aplysia, coincident with the reduced AChE activity is impaired neuron function [17], which chronically applied sensory stimulation (CSS) improves [35]. As a first step to establish the link between the CSS and improved neuronal function, we investigated if CSS alters the level of AChE activity in old Aplysia. Before and after 4 weeks of CSS of the siphon-gill withdrawal reflex (S/GWR), we measured circulating and neural levels of AChE and behaviors involving the gill in freely moving mature and old Aplysia. Only in old animals did the CSS produce increased AChE activity levels in both the CNS and serum, and the increased levels were correlates of a change in the S/GWR, the behavior elicited by the CSS. This result shows that aging animals are able to up regulate enzymatic activity in response to specific sensory input. It also suggests that age influences how the level of AChE activity responds to persistent changes in sensory input. Parallels exist between the results here and those in higher vertebrates and are discussed.
在海洋软体动物海兔中，循环乙酰胆碱酯酶（AChE）活性水平的降低标志着衰老的开始[28]，在哺乳动物中也是如此[23,25]。在老年海兔中，与AChE活性降低同时出现的是神经元功能受损[17]，而长期施加的感觉刺激（CSS）可改善这种情况[35]。作为建立CSS与改善神经元功能之间联系的第一步，我们研究了CSS是否会改变老年海兔中AChE的活性水平。在对虹吸管 - 鳃收缩反射（S/GWR）进行4周的CSS前后，我们测量了自由活动的成熟和老年海兔中AChE的循环水平和神经水平以及涉及鳃的行为。只有在老年动物中，CSS才会使中枢神经系统和血清中的AChE活性水平升高，并且升高的水平与CSS引发的行为S/GWR的变化相关。这一结果表明，衰老动物能够响应特定的感觉输入而上调酶活性。它还表明年龄会影响AChE活性水平对感觉输入持续变化的反应方式。本文的结果与高等脊椎动物的结果存在相似之处，并将进行讨论。
