Taussig R, Kaldany R R, Scheller R H
Proc Natl Acad Sci U S A. 1984 Aug;81(15):4988-92. doi: 10.1073/pnas.81.15.4988.
Single nerve cells can use more than one substance as extracellular chemical messengers. Classical transmitters have been shown to coexist in the same neuron and possibly even in the same vesicle as neuroactive peptides. Furthermore, multiple neuroactive peptides, which are thought to be coreleased, are often encoded in the same precursor assuring stoichiometric synthesis. The precise organization of multiple message systems and the physiological significance of the coexistence is poorly understood. The abdominal ganglion of the gastropod mollusc Aplysia contains a number of identified neurons that are cotransmitter candidates. One such cell, L11, is cholinergic and probably also uses biologically active peptides. Differential screening with labeled cDNA was used to isolate cDNA clones expressed specifically in the bag cells and abdominal ganglion neurons L11 or R15. Analysis of an L11-specific clone suggests that it encodes a 14.7-kDa protein that is the precursor for the secreted peptides. The poly(A)+ RNA transcript is approximately equal to 1.2 kilobases and there are 1-3 copies of this gene in the Aplysia haploid genome.
单个神经细胞可以使用不止一种物质作为细胞外化学信使。经典递质已被证明与神经活性肽共存于同一神经元中，甚至可能存在于同一囊泡中。此外，被认为是共同释放的多种神经活性肽，通常由同一前体编码，以确保化学计量合成。多种信使系统的精确组织以及共存的生理意义仍知之甚少。腹足纲软体动物海兔的腹神经节包含许多被确定为共递质候选者的神经元。其中一个这样的细胞，即L11，是胆碱能的，可能还使用生物活性肽。用标记的cDNA进行差异筛选，以分离在袋状细胞和腹神经节神经元L11或R15中特异性表达的cDNA克隆。对一个L11特异性克隆的分析表明，它编码一种14.7 kDa的蛋白质，该蛋白质是分泌肽的前体。聚腺苷酸加尾RNA转录本约为1.2千碱基，在海兔单倍体基因组中有1至3个该基因的拷贝。
