Primary Cultures of Gabaergic and Glutamatergic Neurons as Model Systems to Study Neurotransmitter Functions I. Differentiated Cells

Abstract

The complexity of the central nervous system (CNS) has necessitated the development of different methodologies, e.g., microdissection, separation by gradient centrifugation, and cell culturing, to study the characteristics of individual cell types. In the present review, we discuss results obtained using one of these preparations, i.e., neurons in primary cultures. By definition such cultures are obtained directly from the living animal, often at an immature stage, and maintained in vitro for at least 24 hours (Fedoroff, 1977). One advantage of the tissue culture system is that it is possible to obtain highly enriched populations of specific cell types. Since the cells are obtained from immature brain tissue, it is, however, essential to ensure that an appropriate development has occurred during the culturing period. Such alterations during development in vitro will be discussed in chapter 3. In this chapter, we discuss characteristics of neurons that have already differentiated during a prolonged culturing period (≃ 2 weeks). The selected characteristics are related to transmitter function, i.e., release, high-affinity uptake, biosynthesis, and receptor interactions of the neurotransmitters γ-aminobutyric acid (GABA) and glutamate. For this purpose, two different culture preparations, i.e., cerebral cortical interneurons and cerebellar granule cells, have been used. From in vivo studies it is known that the cortical interneurons use GABA (Ribak, 1978) and the cerebellar granule cells glutamate (Young et al., 1974; Hudson et al., 1976; Stone, 1979) as their transmitter.