Eisenstadt M, Goldman J E, Kandel E R, Koike H, Koester J, Schwartz J H
Proc Natl Acad Sci U S A. 1973 Dec;70(12):3371-5. doi: 10.1073/pnas.70.12.3371.
We introduced radioactive precursors directly into identified neurons of Aplysia californica. [(3)H]-Choline and L-[(3)H]tryptophan were injected with pressure into nerve cell bodies to study synthesis of acetylcholine and serotonin. We confirmed the cholinergic nature of R2, L10, and L11, identified neurons of the abdominal ganglion. Cells in the LD cluster (which contains motor neurons to the heart and gill) also converted most of the injected choline into acetylcholine. Neurons in the RB cluster (which contains an excitatory motor neuron to the heart) and the two metacerebral cells of the cerebral ganglion converted injected tryptophan to serotonin. No cell studied could convert both choline to acetylcholine and tryptophan to serotonin. Pressure permits rapid injection of precursors, from small amounts to amounts large enough to saturate intracellular synthetic pathways. In contrast to the results with injection, we found far less synthesis of acetylcholine and serotonin in identified nerve cell bodies when ganglia were incubated in the presence of the radioactive precursors.
我们将放射性前体直接注入加州海兔已鉴定的神经元中。将[³H] - 胆碱和L - [³H]色氨酸通过压力注入神经细胞体，以研究乙酰胆碱和5 - 羟色胺的合成。我们证实了腹神经节中已鉴定的神经元R2、L10和L11的胆碱能性质。LD簇中的细胞（其中包含支配心脏和鳃的运动神经元）也将大部分注入的胆碱转化为乙酰胆碱。RB簇中的神经元（其中包含一个支配心脏的兴奋性运动神经元）以及脑神经节的两个大脑细胞将注入的色氨酸转化为5 - 羟色胺。所研究的细胞都不能同时将胆碱转化为乙酰胆碱以及将色氨酸转化为5 - 羟色胺。压力允许从前体的少量到足以饱和细胞内合成途径的大量进行快速注射。与注射结果相反，当神经节在放射性前体存在的情况下孵育时，我们发现在已鉴定的神经细胞体中乙酰胆碱和5 - 羟色胺的合成要少得多。
