An evaluation of selected brain constituents as putative excitatory neurotransmitters

Luini, Alberto; Tal, Nathan; Goldberg, Ora; Teichberg, Vivian I.

doi:10.1016/0006-8993(84)90037-4

Cited by 33 publications

(9 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The low potency of superfused L-Pro may be partly due to active uptake (Peterson & Raghupathy, 1972;Balcar et al, 1976;Hauptmann et al, 1983) in common with other amino acids (Brown et al, 1980;Wood & Sidhu, 1986). L-Glu was six times more potent than L-Pro, which approximates to the relative potency in striatal tissue (Luini et al, 1984). In agreement with the report of Vyclicky et al (1982), a depolarization of the intraspinal fibres of the dorsal roots was also noted (Figure 1).…”

Section: Discussionsupporting

confidence: 80%

l‐Proline depolarizes rat spinal motoneurones by an excitatory amino acid antagonist‐sensitive mechanism

Ault

Wang

Yawn

1987

British J Pharmacology

View full text Add to dashboard Cite

Isolated spinal cords prepared from neonatal rats were used to examine the effects of l‐proline (l‐Pro). l‐Pro (1–8 mm) depolarized ventral and dorsal roots in a dose‐dependent manner with one sixth of the potency of l‐glutamate (l‐Glu). l‐Pro was four times more potent than d‐Pro. Prolonged application of l‐Pro produced a plateau depolarization of motoneurones with no apparent fade. Omission of calcium ions from the medium potentiated the depolarizing actions of l‐Pro, l‐Glu and quisqualate. L‐Pro was antagonized by concentrations of 2‐amino‐5‐phosphonovalerate (25 μm), γ‐d‐glutamylglycine (100 μm) and Mg2+ ions (1 mm) that depressed responses to N‐methyl‐d‐aspartate (NMDA). The NMDA receptor‐mediated component of the response to l‐Pro was estimated to be 60–70%. These data suggest that l‐Pro should be considered as a possible excitatory neurotransmitter and that, because l‐Pro is a neutral compound, excitatory amino acid receptors may not require an agonist to possess two anionic groups and one cationic group.

show abstract

Section: Discussionsupporting

confidence: 80%

l‐Proline depolarizes rat spinal motoneurones by an excitatory amino acid antagonist‐sensitive mechanism

Ault

Wang

Yawn

1987

British J Pharmacology

View full text Add to dashboard Cite

show abstract

“…Low-and highaffinity uptake of L-[~%]HCA was observed in rat cerebral cortex slices (Cox et al, 1977). Both Luini et al (1984) and Baudry et al (1983) observed that DL-HCA was one of the most potent activators of Naf efflux, and suggested that it has a specificity for the NMDA receptor, thus confirming the interpretation of Mewett et al (1983). These conclusions were recently confirmed and extended by Herding and Turski (1986) who, by microiontophoretic application of L-HCA, induced in cat caudate neurons a discharge of the NMDA type, blocked by DL-2amino-7-phosphonoheptanoic acid (AP-7).…”

Section: Release Of Sulfur-containing Amino Acidsmentioning

confidence: 62%

“…In hippocampal slices, the CSA-induced increase of cyclic AMP could be selectively blocked by taurine . L-CSA has been shown to induce a Na+ efflux in rat striatal slices (Luini et al, 1984) and to interact predominantly with non-NMDA receptors in the cat caudate nucleus (Herrling and Turski, 1985). It is thus surprising that no release was detected for endogenous CSA in the rat striatum in the present study.…”

Section: Release Of Sulfur-containing Amino Acidsmentioning

confidence: 99%

In Vitro Release of Endogenous Excitatory Sulfur‐Containing Amino Acids from Various Rat Brain Regions

Mattenberger

Streit

et al. 1986

Journal of Neurochemistry

151

View full text Add to dashboard Cite

Efflux of various amino acids from rat brain slices was determined under resting or depolarizing conditions. Slices of neocortex, hippocampus, striatum, cerebellum, mesodiencephalon, pons-medulla, and spinal cord were depolarized by K+ (50 mM) or veratrine (33 micrograms/ml). The 4-N,N-dimethylamino-azobenzene-4'-isothiocyanate (DABITC) derivatization method of Chang [Biochem. J. 199, 537-545 (1981)] for HPLC was adapted for analysis of amino acids and peptides in superfusion solutions. It allowed the separation and simultaneous detection of the sulfur-containing amino acids cysteine sulfinic acid (CSA), cysteic acid (CA), homocysteine sulfinic acid (HCSA), and homocysteic acid (HCA) at the picomole level. All four were shown to be released on depolarization in a Ca2+-dependent manner from brain slices. CSA and HCSA were released from cortex, hippocampus, mesodiencephalon, and, for HCSA only, striatum. HCA release, observed in all regions, was most prominent in cortex and hippocampus. CA was slightly increased by depolarization in hippocampus and mesodiencephalon. These sulfur-containing amino acids have been shown to exert an excitatory action on CNS neurons. The fact that these sulfur-containing amino acids are released as endogenous substances from nervous tissue supports the hypothesis that they play a role in CNS neurotransmission.

show abstract

“…While the specificity of NAAG for the NMDA class of glutamate receptors on these cells favors a role for the dipeptide in spinal neurotransmission, its low potency relative to glutamate may militate against a neurotransmitter function (Westbrook et al, 1986). The failure of NAAG to significantly affect, as an excitatory amino acid receptor agonist or antagonist, sodium efflux from rat striatum slices under conditions in which the four classes of receptors could be demonstrated also suggests that the dipeptide's neurotransmitter role may be difficult to demonstrate (Luini et al, 1984). Assays of NAAG release upon depolarization of neurons in the spinal sensory axis or elsewhere in the nervous system will contribute to the resolution of this question.…”

Section: Discussionmentioning

confidence: 99%

Immunohistochemistry and Biosynthesis of N‐Acetylaspartylglutamate in Spinal Sensory Ganglia

Cangro

Namboodiri

Sklar

et al. 1987

Journal of Neurochemistry

114

View full text Add to dashboard Cite

N-Acetylaspartylglutamate (NAAG) is a nervous system-specific dipeptide which has been implicated in chemical neurotransmission. Antisera were prepared against NAAG in order to study its cellular distribution. When these antisera were applied to tissue sections of rat spinal sensory ganglia, NAAG-like immunoreactivity was detected within a subpopulation of relatively large neuronal cell bodies in cervical, lumbar, and thoracic ganglia. In order to confirm the presence of NAAG within these neurons, the dipeptide was extracted and purified from spinal ganglia using high-performance liquid chromatography and its composition confirmed by amino acid analysis. Further, the biosynthesis of NAAG was studied in vitro by following the incorporation of either [3H]glutamine or [3H]glutamate into the glutamate residue of the purified dipeptide. [3H]Aspartate was not incorporated efficiently into NAAG under these conditions, suggesting a precursor role for the large N-acetylaspartate pool. The incorporation of radiolabeled amino acids into newly synthesized NAAG by spinal sensory ganglia was not inhibited by incubation of the cells with anisomycin or cycloheximide at concentrations which significantly inhibited protein synthesis. These data suggest that NAAG is present in a subpopulation of primary afferent spinal neurons and that its biosynthesis is mediated by a dipeptide synthetase.

show abstract

An evaluation of selected brain constituents as putative excitatory neurotransmitters

Cited by 33 publications

References 35 publications

l‐Proline depolarizes rat spinal motoneurones by an excitatory amino acid antagonist‐sensitive mechanism

l‐Proline depolarizes rat spinal motoneurones by an excitatory amino acid antagonist‐sensitive mechanism

In Vitro Release of Endogenous Excitatory Sulfur‐Containing Amino Acids from Various Rat Brain Regions

Immunohistochemistry and Biosynthesis of N‐Acetylaspartylglutamate in Spinal Sensory Ganglia

Contact Info

Product

Resources

About