Abstract
The recent identification of two genes encoding distinct forms of the GABA synthetic enzyme, glutamate decarboxylase (GAD), raises the possibility that varying expression of the two genes may contribute to the regulation of GABA production in individual neurons. We investigated the postnatal development the two forms of GAD in the rat cerebellum. The mRNA for GAD67, the form which is less dependent on the presence of the cofactor, pyridoxal phosphate (PLP), is present at birth in presumptive Purkinje cells and increases during postnatal development. GAD67 mRNA predominates in the cerebellum. The mRNA for GAD65, which displays marked PLP-dependence for enzyme activity, cannot be detected in cerebellar cortex by in situ hybridization until P7 in Purkinje cells, and later in other GABA neurons. In deep cerebellar nuclei, which mature prenatally, both forms of GAD mRNA can be detected at birth. The amounts of immunoreactice GAD and GAD enzyme activity parallel changes in mRNA levels. We suggest that the delayed appearance of GAD65 is coincident with synapse formation between GABA neurons and their targets during the second postnatal week. GAD67 mRNA may be present prior to synaptogenesis to produce GABA for trophic and metabolic functions.
Similar content being viewed by others
References
Erlander, M.G., and Tobin, A.J. 1991. The structural and functional heterogeneity of glutamic acid decarboxylase: a review. Neurochem. Res. 16:215–226.
Kaufman, D.L., McGinnis, J.F., Krieger, N.R. and Tobin, A.J. 1986. Brain glutamate decarboxylase cloned in λgt-11: Fusion protein produces γ-aminobutryic acid. Science 232:1138–1140.
Kobayashi, Y., Kaufman, D.L. and Tobin, A.J. 1987. Glutamic acid decarboxylase cDNA: Nucleotide sequence encoding an enzymatically active fusion protein. J. Neurosci. 7:2768–2772.
Nitsch, C. 1980. Regulation of GABA metabolism in discrete rabbit brain regions under methoxypyridoxine — regional differences in cofactor saturation and the preictal activation of glutamate decarboxylase activity. J. Neurochem. 34:822–830.
Itoh, M., and Uchimura, H. 1981. Regional differences in cofactor saturation of glutamate decarboxylase (GAD) in discrete brain nuclei of the rat: Effects of repeated administration of haloperidol on GAD activity in the substantia nigra. Neurochem. Res. 6:1283–1289.
Denner, L.A., and Wu, J.-Y. 1985. Two forms of rat brain glutamic acid decarboxylase differ in their dependence on free pyridoxal phosphate. J. Neurochem. 44:957–965.
Wuenschell, C.W., Fisher, R.S., Tillakaratne, N.J.K. and Tobin, A.J. 1986. In situ detection of GAD mRNA in mouse brain. Pages 135–149,in Uhl, G.R., (ed.) In situ Hybridization in Brain, Plenum Publishing Co., N.Y.
Kluver, N., and Barrera, E. 1953. A method for combined staining of cells and fibers in the nervous system. J. Neuropath. Exp. Neurol. 12:400–403.
Chomczynski, P., and Sacchi, N. 1987. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloro-form extraction. Anal. Biochem. 162:156–159.
Maniatis, T., Fritsch, E.F., and Sambrook, J. 1982. Molecular cloning: A laboratory manual. Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.
Krieger, N.R., and Heller, J.S. 1984. Localization of GAD within laminae of rat olfactory tubercle. J. Neurochem. 33:299–309.
Kaufman, D.L., Houser, C.R., and Tobin, A.J. 1991. Two forms of the GABA synthetic enzyme glutamate decarboxylase have distinct intraneuronal distributions and cofactor interactions. J. Neurochem. 56:720–723.
Oertel, W.H., Schmechel, D.E., Tappaz, M.L., and Kopin, I.J. 1981. Production of a specific antiserum to rat brain glutamic acid decarboxylase by injection of an antigen-antibody complex. Neurosci. 6:2689–2700.
Altman, J. 1972. Postnatal development of the cerebellar cortex in the rat I. The external germinal layer and the transitional molecular layer. J. Comp Neurol. 145:353–398.
Altman, J. 1972. Postnatal development of the cerebellar cortex in the rat II. Phases in the maturation of Puriinje cells and of the molecular layer. J. Comp. Neurol. 145:399–464.
Altman, J. 1972. Postnatal development of the cerebellar cortex in the rat III. Maturation of components of the granular layer. J. Comp. Neurol. 145:465–514.
Altman, J., and Bayer, S.A. 1978. Prenatal development of the cerebellar system in the rat I. Cytogenesis and histogenesis of the deep nuclei and the cortex of the cerebellum. J. Comp. Neurol. 179:23–48.
Altman, J., and Bayer, S.A. 1985. Embryonic development of the rat cerebellum III. Regional differences in the time of origin, migration and settling of Purkinje cells. J. Comp. Neurol. 231:42–65.
McLaughlin, B.J., Wood, J.G., Saito, K., Roberts, E., and Wu, J.-Y. 1975. The fine structural localization of glutamate decarboxylase in developing axonal processes and presynaptic terminals in rodent cerebellum. Brain Res. 85:355–371.
Seiler, N., and Lajtha, A. 1987. Functions of GABA in the vertebrate organism. Pages 1–56in D.A. Redburn and A. Schousbor, (eds) Neurotrophic activity of GABA during development. Alan R. Liss, Inc., N.Y.
McGeer, P.L. and McGeer, E.G. 1989. Amino acid neurotransmitters. Pages 311–332,in G.J. Siegel et al. (eds.) Basic Neurochemistry: Molecular, Cellular and Medical Aspects, 4th Edition. Raven Press, Ltd., N.Y.
Shimono, T., Nosaka, S., and Sasaki, K. 1976. Electrophysiological study on the postnatal development of neuronal mechanisms in the rat cerebellar cortex. Brain Res. 108:279–294.
Woodward, D.J., Hoffer, B.J., Siggins, G.R., and Bloom, F.E. 1971. The ontogenetic development of synaptic junctions, synaptic activation and responsiveness to neurotransmitter substances in rat cerebellar Purkinje cells. Brain Res. 34:73–97.
Tobin, A.J. 1979. Evaluating the contribution of posttranscriptional processing to differential gene expression. Devel. Biol. 68:47–58.
Author information
Authors and Affiliations
Additional information
Special issue dedicated to Dr. Eugene Roberts.
Rights and permissions
About this article
Cite this article
Greif, K.F., Erlander, M.G., Tillakaratne, N.J.K. et al. Postnatal expression of glutamate decarboxylases in developing rat cerebellum. Neurochem Res 16, 235–242 (1991). https://doi.org/10.1007/BF00966086
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00966086