Free amino acids in the synaptosome and synaptic vesicle fractions of different bovine brain areas

Kontro, P.; Marnela, Kirsi-Marja; Oja, Simo S.

doi:10.1016/0006-8993(80)90592-2

Cited by 108 publications

(29 citation statements)

References 28 publications

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“…Taken together, the measurements for internal dialysis, direct taurine binding assays, and axoplasmic diffusion comprise a strong body of evidence against the possibility that there is significant specific binding or compartmentalization of amino acids in the axoplasm of giant axons. This conclusion applies to the axon only and may not be true for specialized regions such as the nerve terminal or the soma (Kontro et al, 1980). Taurine efflux from Myxicola giant axons occurs by at least one saturable, mediated process, and by an apparent diffusive "leak" with a very low permeability.…”

Section: Discussionmentioning

confidence: 95%

Measurements of amino acid transport in internally dialyzed giant axons

Horn

1986

J. Membrain Biol.

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It is shown that the axoplasmic composition of acidic and neutral amino acids can be controlled effectively by the method of internal dialysis. Direct assay for specific binding and measurement of diffusion coefficients in axoplasm show that there is no significant binding or compartmentalization of amino acids. The dependence of amino acid efflux on substrate concentration can be measured under well-defined, true steady-state conditions. The taurine efflux-concentration relation in the Myxicola giant axon conforms to a second-order Hill equation. This fact is consistent with either a cooperative process or a mechanism in which membrane translocation is not the rate-controlling step. The effluxes of taurine and glycine from squid axon are an order of magnitude smaller than in Myxicola. The efflux-concentration relations are essentially linear up to 200 mM substrate concentration. This result may be produced by specific transporters which have very high asymmetry, or by simple diffusive leak in the absence of specific transporters.

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Section: Discussionmentioning

confidence: 95%

Measurements of amino acid transport in internally dialyzed giant axons

Horn

1986

J. Membrain Biol.

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“…Taurine was reported to has function in neurotransmission in the nerve ending of rat brains (14) and cysteic acid decarboxylase (CAD) seems to be the key enzyme for its synthesis in vwo (15). Attempts have been taken to monitor the activity level of some enzymes involved in the metabolism of neurotransmitter amino acids in different vertebrate brains (16)(17)(18).…”

Section: Biochemistry and Molecular Biology Internationalmentioning

confidence: 99%

Ontogeny of neurotransmitter amino acids in human fetal brains

Das

Ray

1997

IUBMB Life

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SUMMARYA wide spectrum of developmental profiles is presented for a few important neurotransmitter amino acids, namely ?-aminobutyric acid, glycine, glutamic acid, aspartic acid and taurine as well as the key enzymes involved in their metabolism in human fetal brains of different gestational ages. Besides taurine almost all these amino acids and their key metabolic enzymes were found to be progressively enhanced upto the mid period of third trimester of pregnancy indicating a rapid growth of nerve processes, myelination and maturation of fetal brains particularly during this period. Inteiestingly taurine showed an inverse relationship of ontogenic pattern with respect to its biosynthesizing enzyme in fetal brains.

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“…Extracellular taurine concentration can be increased after sodium-taurine cotransport is blocked by guanidinoethylsulWnate (Kishi et al, 1988). Taurine is found to be ubiquitously present in synaptic vesicles (Kontro et al, 1980) although calcium-activated synaptic release of taurine has not been identiWed. Since its Wrst discovery in 1827, taurine has been shown by numerous studies to have Abbreviations: ACSF, artiWcial cerebrospinal Xuid; AMPA, -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid; APV, DL-2-amino-5-phosphonovaleric acid; ATP, adenosine-5Ј-triposphate; Bic, bicuculline; CIC, the commissure of the inferior colliculus; CNQX, 6-cyano-7-nitroquinoxaline-2,3-dione; eEPSC, evoked excitatory postsynaptic current; EGTA, ethyleneglykole-bis-(2-aminoethyl)-tetraacetic acid; eIPSC, evoked inhibitory postsynaptic current; ePSC, evoked postsynaptic current; GABA, -aminobutyric acid; GABA A R, -aminobutyric acid type A receptor; Glu, glutamate; GlyR, glycine receptor; GTP, guanosine-5Ј-triphosphate; HEPES, 4-(2-hydroxyethyl)piperaxine-1-ethanesulfonic acid; IC, the inferior colliculus; ICC, the central nucleus of the inferior colliculus; LL, the lateral lemniscus; NMDA, N-methyl-D-aspartate; ; sPSC, spontaneous postsynaptic current various physiological functions and play an essential role in neural development (Huxtable, 1989(Huxtable, , 1992(Huxtable, , 2000Saransaari and Oja, 2000;Sturman, 1993).…”

Section: Introductionmentioning

confidence: 98%