INTRACELLULAR INJECTION OF THE CATALYTIC SUBUNIT OF CYCLIC AMP-DEPENDENT PROTEIN-KINASE SIMULATES FACILITATION OF TRANSMITTER RELEASE UNDERLYING BEHAVIORAL SENSITIZATION IN APLYSIA
INTRACELLULAR INJECTION OF THE CATALYTIC SUBUNIT OF CYCLIC AMP-DEPENDENT PROTEIN-KINASE SIMULATES FACILITATION OF TRANSMITTER RELEASE UNDERLYING BEHAVIORAL SENSITIZATION IN APLYSIA
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DOI：
10.1073/pnas.77.12.7492
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
GREENGARD, P
中科院分区：
文献类型：
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作者：
CASTELLUCCI, VF;KANDEL, ER;GREENGARD, P
神经细胞中camp介导的蛋白磷酸化是否在突触传递中起特定作用一直难以确定。这一困难在高等无脊椎动物中可以克服，因为它们的大神经元允许将蛋白质分子注射到细胞中。细胞内注射用于研究蛋白磷酸化是否参与致敏机制，这是一种简单的学习形式。鳃退缩反射的敏化涉及通过突触前促进在一组特定的突触连接中识别的感觉神经元及其跟随细胞之间的递质释放的增强。从牛心脏纯化的camp依赖性蛋白激酶的催化亚基通过模拟伴随突触前促进的生理变化来模拟天然递质和血清素（假定的递质）的作用。细胞内注入激酶到感觉细胞中，在四乙基铵存在的情况下，动作电位变宽，表明Ca2+电流增加，降低细胞的输入电导，可能是由于K+电流减少的结果，并且增加了感觉细胞末端向跟随神经元释放的递质量。
It has been difficult to establish whether cAMP-mediated protein phosphorylation in nerve cells plays a specific role in synaptic transmission. This difficulty can be overcome in higher invertebrates because their large neurons allow the injection of protein molecules into the cell. Intracellular injection was used to study whether protein phosphorylation is involved in the mechanism of sensitization, a simple form of learning. Sensitization of the gill-withdrawal reflex in Aplysia involves enhancement of transmitter release by presynaptic facilitation at a particular set of synaptic connections between identified sensory neurons and their follower cells. Injection of the catalytic subunit of cAMP-dependent protein kinase purified from bovine heart mimics the action of the natural transmitter and of serotonin, the putative transmitter, by simulating the physiological changes that accompany presynaptic facilitation. Intracellular injection of the kinase into a sensory cell broadens the action potential in the presence of tetraethylammonium, indicating an increase in Ca2+ current, decreases the input conductance of the cell, presumably as a result of a decrease in the K+ current, and increases the amount of transmitter released by terminals of the sensory cell onto follower neurons.