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Hutchinson PJ, O'Connell MT, Kirkpatrick PJ, Pickard JD. How can we measure substrate, metabolite and neurotransmitter concentrations in the human brain? Physiol Meas 2002; 23:R75-109. [PMID: 12051319 DOI: 10.1088/0967-3334/23/2/202] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cerebral injury and disease is associated with fundamental derangements in metabolism, with changes in the concentration of important substrates (e.g. glucose), metabolites (e.g. lactate) and neurotransmitters (e.g. glutamate and y-aminobutyric acid) in addition to changes in oxygen utilization. The ability to measure these substances in the human brain is increasing our understanding of the pathophysiology of trauma, stroke, epilepsy and tumours. There are several techniques in clinical practice already in use and new methods are under evaluation. Such techniques include the use of cerebral probes (e.g. microdialysis. voltammetry and spectrophotometry) and functional imaging (e.g. positron emission tomography and magnetic resonance spectroscopy). This review describes these techniques in terms of their principles and clinical applications.
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Affiliation(s)
- P J Hutchinson
- Department of Neurosurgery and Wolfson Brain Imaging Centre, Addenbrooke's Hospital, University of Cambridge, UK.
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Abstract
A number of modern techniques now allow histologists to characterize subpopulations of retinal neurons by their neurotransmitters. The morphologies and connections of these chemically defined neurons can be analyzed precisely at both light and electron microscope levels and lead to a better understanding of retinal circuitry. The dopaminergic neurons form a loose population of special wide-field amacrine cells bearing intraretinal axons within the inner plexiform layer. One subtype, the interplexiform cell, sends an axon to the outer plexiform and outer nuclear layers. The number of interplexiform cells is variable throughout mammalian species. The GABAergic neurons form a dense and heterogeneous population of amacrine cells branching at all levels of the inner plexiform layer. The presence of GABA in horizontal cells seems to be species-dependent. Close relationships occur between dopaminergic and GABAergic cells. GABA antagonizes a number of dopaminergic actions by inhibiting both the release and synthesis of dopamine. This inhibition can be supported by GABA synapses onto dopaminergic cells, but GABA can also diffuse to its targets. Finally, GABA is also contained and synthesized in dopaminergic cells. This colocalization might be the basis of an intracellular modulation of dopamine by GABA.
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Affiliation(s)
- J Nguyen-Legros
- Laboratoire de Neurocytologie Oculaire, INSERM U-86, Paris, France
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Tang X, Hsu CC, Sun Y, Wu E, Yang CY, Wu JY. Multiplicity of Brain Cysteine Sulfinic Acid Decarboxylase - Purification, Characterization and Subunit Structure. J Biomed Sci 1996; 3:442-453. [PMID: 11725125 DOI: 10.1007/bf02258048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Cysteine sulfinic acid decarboxylase (CSAD), the rate-limiting enzyme in taurine biosynthesis, appears to be present in the brain in multiple isoforms. Two distinct forms of CSAD, referred to as CSAD I and CSAD II, were obtained on Sephadex G-100 column. CSAD I and CSAD II differ in: (1) the elution profile on Sephadex G-100 column; (2) the sensitivity towards Mn(2+), methione, and other sulfur-containing amino acids, and (3) their immunologic properties. CSAD II has been purified to about 2,500-fold by a combination of column chromatographies and polyacrylamide gel electrophoresis (PAGE). The purity of the enzyme preparation was established as judged from the following observations: (1) a single protein band was observed under various electrophoretic conditions, e.g., 5-20% nondenaturing PAGE, 7% nondenaturing PAGE and 10% SDS-PAGE, and (2) in nondenaturing PAGE, the protein band comigrated with CSAD activity. CSAD II has a molecular weight of 90 kDa and is a homodimer consisting of two 43 +/- 2 kDa subunits. CSAD appears to require Mn(2+) for its maximum activity. Other divalent cations fail to replace Mn(2+) in activation of CSAD activity. However, the precise role of Mn(2+) in the action of CSAD remains to be determined. Copyright 1996 S. Karger AG, Basel
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Affiliation(s)
- X.W. Tang
- Department of Physiology and Cell Biology, University of Kansas, Lawrence, Kans., USA
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Szabat E, Soinila S, Häppölä O, Linnala A, Virtanen I. A new monoclonal antibody against the GABA-protein conjugate shows immunoreactivity in sensory neurons of the rat. Neuroscience 1992; 47:409-20. [PMID: 1641131 DOI: 10.1016/0306-4522(92)90255-z] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A monoclonal antibody, 115AD5, was raised against GABA coupled to bovine serum albumin. The monoclonal antibody 115AD5 also reacted with other GABA-protein conjugates. The specificity of the monoclonal antibody was corroborated by enzyme-linked immunoassay, dot-immunobinding experiments and immunostaining of rat cerebellum sections. The monoclonal antibody 115AD5 could successfully be applied on Vibratome and cryostat sections using either indirect immunofluorescence or peroxidase techniques. In rat cerebellar cortex the monoclonal antibody 115AD5 gave an intense immunoreaction in stellate cells, in Golgi neurons, and in basket cells and their processes around Purkinje cell bodies. Purkinje cell dendrites showed GABA immunoreactivity while the cell bodies were non-reactive or only weakly reactive. There was labelling in some nuclei of Purkinje cells. GABA immunoreactivity was also found in dot-like structures in the granular layer. A large population of sensory neurons in rat thoracic and lumbar spinal dorsal root ganglia presented an intense immunoreactivity for the monoclonal antibody 115AD5. Nerve bundles immunoreactive for GABA were also seen in these ganglia. In the trigeminal ganglion, a major population of sensory neurons and some of their processes presented immunoreactivity for GABA. In the sensory nodose ganglion of the vagus nerve, many neuronal cell bodies and some fibres were immunoreactive for GABA. Ligation of the vagus nerve caudal to the ganglion resulted in an increased GABA immunoreactivity in neuronal somata of the ganglion, as well as in nerve fibres on the ganglionic side of the ligature. The present results suggest that in the rat, a population of sensory neurons in thoracic and lumbar spinal dorsal root ganglia, as well as in the trigeminal and nodose ganglia contain GABA. The presence of GABA immunoreactivity in these neurons raises the possibility of a neurotransmitter or modulator role.
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Affiliation(s)
- E Szabat
- Department of Anatomy, University of Helsinki, Finland
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Erlander MG, Tobin AJ. The structural and functional heterogeneity of glutamic acid decarboxylase: a review. Neurochem Res 1991; 16:215-26. [PMID: 1780024 DOI: 10.1007/bf00966084] [Citation(s) in RCA: 340] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Studies of the GABA-synthetic enzyme glutamate decarboxylase (glutamic acid decarboxylase; GAD; E.C.4.1.1.15) began in 1951 with the work of Roberts and his colleagues. Since then, many investigators have demonstrated the structural and functional heterogeneity of brain GAD. At least part of this heterogeneity derives from the existence of two GAD genes.
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Affiliation(s)
- M G Erlander
- Neuroscience Program, University of California, Los Angeles 90024
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Legay F, Pelhate S, Tappaz ML. Phylogenesis of brain glutamic acid decarboxylase from vertebrates: immunochemical studies. J Neurochem 1986; 46:1478-86. [PMID: 3083046 DOI: 10.1111/j.1471-4159.1986.tb01765.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Brain high-speed supernatants from various lower and higher vertebrates were subjected to sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, electroblot on nitrocellulose membranes, and immunolabelling using an anti-glutamic acid decarboxylase (anti-GAD) antiserum prepared from rat antigen. Rat brain extracts showed two distinct immunolabelled bands (MW 59,000 and 62,000 daltons). The molecular weight of the native enzyme was 120,000 daltons. The immunoblot pattern was not affected by a 3-h incubation of the homogenate. In the substantia nigra, the decrease in the immunolabelling of both bands corresponded very closely to the decrease of GAD activity following lesioning of the striato-nigral pathway. Moreover, experiments with preadsorbed antiserum showed that both subunits have common antigenic determinants. The immunolabelling was consistently more intense over the lightest band. The autoradiography of immunoprecipitated rat brain GAD, iodinated prior to electrophoresis, revealed two radiolabelled bands corresponding to the two immunolabelled ones. Their radioactivity was found in a one-to-five ratio which closely paralleled their respective immunolabelling intensity. Thus, the two subunits recognized by the antiserum are not present in stoichiometric proportions in the rat brain high-speed supernatant. These findings suggest the existence of two homodimeric GAD with common antigenic determinants which are present in different amounts. Immunoprecipitation curves of brain GAD from rat, mouse, rabbit, monkey, human, quail, frog, and trout were similar, with a less than 10-fold maximum shift in affinity for GAD. GAD immunoblots from the various higher vertebrates showed a pattern similar to that obtained in rat.(ABSTRACT TRUNCATED AT 250 WORDS)
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Brandon C. Purification of L-glutamate decarboxylase from rabbit brain and preparation of a monospecific antiserum. J Neurosci Res 1986; 15:367-81. [PMID: 2422389 DOI: 10.1002/jnr.490150308] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
L-Glutamate decarboxylase (GAD), the enzyme responsible for the biosynthesis of gamma-aminobutyric acid, has been purified from rabbit brain and used for the production of a monospecific rabbit antiserum. The enzyme was purified approximately 500-fold by a combination of ion exchange, hydrophobic, hydroxyapatite, and gel filtration column chromatography, and preparative polyacrylamide gel electrophoresis. The preparation thus obtained was injected into a rabbit, producing a polyspecific antiserum. This first antiserum was used for the preparation of an immunoprecipitate containing GAD; injections of the immunoprecipitate into a second rabbit led to the production of a second, monospecific anti-GAD serum. The specificity of the antiserum for GAD has been demonstrated by enzyme precipitation, immunodiffusion, line immunoelectrophoresis, gel filtration chromatography of GAD/anti-GAD immune complexes, and immunocytochemistry in the rat cerebellum.
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Gombos G, Aunis D. Enzymes of neurotransmitter metabolism as neuronal markers in the central nervous system. SCANDINAVIAN JOURNAL OF IMMUNOLOGY. SUPPLEMENT 1982; 9:317-38. [PMID: 6134337 DOI: 10.1111/j.1365-3083.1982.tb03771.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
The subcellular distribution of glutamate decarboxylase (GAD) was revealed by electron microscopic immunocytochemistry in primary cultures of the rat neostriatum. Immunoreactivity was restricted to a small nerve cell type with rich amounts of free ribosomes and an indented nucleus. Glial cells were non-reactive. The results indicate that GABA-synthesizing neurons are viable in culture conditions and suggest that neostriatal GABA-neurons are small cells with simple ultrastructure since larger cells did not possess immunoreactivity.
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Pérez de la Mora M, Possani LD, Tapia R, Teran L, Palacios R, Fuxe K, Hökfelt T, Ljungdahl A. Demonstration of central gamma-aminobutyrate-containing nerve terminals by means of antibodies against glutamate decarboxylase. Neuroscience 1981; 6:875-95. [PMID: 6787456 DOI: 10.1016/0306-4522(81)90169-x] [Citation(s) in RCA: 147] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Demonstration of glutamate decarboxylase-immunoreactive neurones in cultures of rat substantia nigra. Neurosci Lett 1981. [DOI: 10.1016/0304-3940(81)90123-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Panula P, Emson P, Wu JY. Demonstration of enkephalin-, substance P- and glutamate decarboxylase-like immunoreactivity in cultured cells derived from newborn rat neostriatum. HISTOCHEMISTRY 1980; 69:169-79. [PMID: 6161908 DOI: 10.1007/bf00533134] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The presence of cells exhibiting leucine-enkephalin-, substance P- and glutamate decarboxylase-like immunoreactivity was demonstrated in dissociated cultures from newborn rat neostriatum. The size and shape of the enkephalin-immunoreactive cells varied, but they were generally larger than substance P- and glutamate decarboxylase-immunoreactive cells, which formed relatively uniform cell populations. Cells of apparently non-neuronal origin did not show any immunoreactivity. It is unlikely that enkephalin is present in the same cells that contain substance P or glutamate decarboxylase because of morphological differences between these cells. The possible coexistence of substance P and glutamate decarboxylase in the same cells however, could not be excluded. The results of this study confirm that the cell bodies of neurons containing three possible neurotransmitters are located in the neostriatum.
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Abstract
Much progress has been made in recent years regarding enzymological aspects of mammalian brain GAD, such as its purification and characterization, but some uncertainty still remains concerning its molecular weight and forms, and its subunit structure. The availability of antibodies to this enzyme has allowed immunocytochemical studies which have provided important information on the intrinsic organization of GABA-ergic neurones in the CNS, particularly in the cerebellum and nigrostriatal pathway. With the increased understanding of the enzymology of GAD and the distribution of central GABA-ergic neurones, it is becoming feasible to study the regulatory biochemistry of GAD in terms of control and adaptive mechanisms at the cellular level. In our own laboratory, as well as in others, initial approaches have already begun. Obviously, cellular regulation of this phenotypic enzyme is an important issue for the understanding of GABA-ergic neurones and their functions.
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Kuwano R, Takahashi Y. A simple method for the preparation of the immunoglobulins to hydroxyindole O-methyltransferase. J Neurochem 1978; 31:809-14. [PMID: 100575 DOI: 10.1111/j.1471-4159.1978.tb00115.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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?Immunohistochemical localization of choline acetyltransferase: Real or artefact?? A reply. Neurochem Res 1977; 2:323-5. [DOI: 10.1007/bf00969362] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/1976] [Indexed: 11/26/2022]
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Fisher SK, Davies WE. Some properties of guinea pig brain glutamate decarboxylase and its inhibition by the convulsant allylglycine (2-amino-4-pentenoic acid). J Neurochem 1974; 23:427-33. [PMID: 4153560 DOI: 10.1111/j.1471-4159.1974.tb04375.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Schon F, Iversen LL. The use of autoradiographic techniques for the identification and mapping of transmitter-specific neurones in the brain. Life Sci 1974; 15:157-75. [PMID: 4157267 DOI: 10.1016/0024-3205(74)90205-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Saito K, Wu JY, Matsuda T, Roberts E. Immunochemical comparisons of vertebrate glutamic acid decarboxylase. Brain Res 1974; 65:277-85. [PMID: 4214149 DOI: 10.1016/0006-8993(74)90039-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Matsuda T, Wu JY, Roberts E. Electrophoresis of glutamic acid decarboxylase (EC 4.1.1.15) from mouse brain in sodium dodecyl sulphate polyacrylamide gels. J Neurochem 1973; 21:167-72. [PMID: 4720893 DOI: 10.1111/j.1471-4159.1973.tb04236.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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