Putative neurotransmitters in clonal cell lines

Abstract

THE regional distribution of putative neurotransmitters in the mammalian central nervous system (CNS) has been studied often (for example, refs 1–4). Although in some cases neurotransmitter synthesis has been correlated with nervous function, its distribution among different cell types has not been assayed. For example, the distribution of the putative neurotransmitters taurine and γ-aminobutyric acid (GABA) between nerve and glia has not been established using in vivo preparations. Another approach is to use clonal cell lines derived from the CNS, for their cellular homogeneity facilitates the assay of pool sizes of neurotransmitters and free amino acids in identified cells. Such determinations have been made with fibroblasts5–7. The expanding collection of clonal cell lines from the CNS8–11 and other tissues (for example, refs 12–14) presents the opportunity to extend this approach. We describe here the free amino acid pools of some cell lines from the CNS and other tissues which exhibit differentiated phenotypes. We have found that although several specific differences exist between cells from different tissues, there is a strong similarity between different cell types of common embryological origin.