Localization ofl-glutamate binding sites in chick brain by quantitative autoradiography

Mitsacos, Ada; Dermon, Catherine R.; Stassi, K.; Kouvelas, Elias D.

doi:10.1016/0006-8993(90)90480-y

Cited by 19 publications

(15 citation statements)

References 29 publications

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“…The present quantitative autoradiographic study of normal human cerebellum indicated the presence of Lglutamate binding sites in both molecular and granule cell layers, with higher levels of binding in the molecular layer. These results are in agreement with those obtained in previous autoradiographic studies using rat, mouse, and chick cerebellar tissue (Greenamyre et al, 1984(Greenamyre et al, , 1985aHalpain et al, 1984;Monaghan et al, 1985;Olson et al, 1987;Mitsacos et al, 1990). Considerable evidence supports the concept that L-glutamate serves as the excitatory neurotransmitter of parallel fibers of granule cells in the molecular layer of cerebellum (Fagg and Foster, 1983).…”

Section: Inhibition Of L-[3h]glutamate Bindingsupporting

confidence: 94%

Quantitative autoradiographic study of L‐glutamate binding sites in normal and atrophic human cerebellum

Hatziefthimiou

Mitsacos

Mitsaki

et al. 1991

J of Neuroscience Research

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In the present work the distribution of L-glutamate binding sites in the different layers of human cerebellum of normal individuals and of seven patients who died with olivopontocerebellar atrophy (OPCA) was examined with the technique of quantitative autoradiography. Specific L-[3H]glutamate binding was higher in the molecular than in the granule cell layer of normal cerebellar tissue. A significant decrease of L-[3H]glutamate specific binding was observed in the molecular layer of all OPCA tissues. In the granule cell layer L-[3H]glutamate binding was decreased only in two patients who suffered from late-onset sporadic OPCA and in one patient who suffered from a form of OPCA inherited in a dominant manner. Quisqualate-sensitive binding sites were the most abundant binding sites in the molecular layer of normal cerebella, whereas N-methyl-D-aspartic acid (NMDA)-sensitive binding sites were the most abundant type in the granule cell layer. A significant decrease of quisqualate-sensitive and an increase in NMDA-sensitive binding sites were observed in the molecular layer of OPCA cerebellar tissues. No significant changes were observed in the granule cell layer of these tissues.

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Section: Inhibition Of L-[3h]glutamate Bindingsupporting

confidence: 94%

Quantitative autoradiographic study of L‐glutamate binding sites in normal and atrophic human cerebellum

Hatziefthimiou

Mitsacos

Mitsaki

et al. 1991

J of Neuroscience Research

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“…This is perhaps not surprising, given that fast excitatory transmission via excitatory amino acid receptors is thought to take place throughout the auditory system (cochlear nuclei: Nemeth et al, 1983;Martin, 1985;Hunter et al, 1993;lateral superior olive: Caspary and Faingold, 1989;Finlayson and Caspary, 1989;nucleus laminaris: Zhou and Parks, 199 1; medial nucleus of the trapezoid body: Forsythe and Barnes-Davies, 1993). In addition, this finding is consistent with the presence of glutamate binding sites in the chick's IC (Mitsacos et al, 1990) and the (Greenamyre et al, 1984;Cotman and Iversen, 1987) with the presence of glutamate-immunoreactive neurons in the rat's IC (Otterson and Storm-Mathisen, 1984), and with previous evidence showing that NMDA receptor antagonists reduce auditory responses in the rat's IC (Faingold et al, 1989b).…”

Section: Discussionmentioning

confidence: 65%

“…Glutamate binding sites exist in chick IC (Mitsacos et al, 1990), but it is not known if these sites represent receptors that mediate auditory responses, nor is it known which subtypes of glutamate receptor they represent. In the mammalian IC, there is strong evidence suggesting that auditory transmission is mediated by an excitatory amino acid.…”

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confidence: 99%

NMDA and non-NMDA glutamate receptors in auditory transmission in the barn owl inferior colliculus

Feldman

Knudsen

1994

J. Neurosci.

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The pharmacology of auditory responses in the inferior colliculus (IC) of the barn owl was investigated by iontophoresis of excitatory amino acid receptor antagonists into two different functional subdivisions of the IC, the external nucleus (ICx) and the lateral shell of the central nucleus (lateral shell), both of which carry out important computations in the processing of auditory spatial information. Combined application of the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (AP5) and the non-NMDA receptor antagonist 6-cyano-5-nitroquinoxaline-2,3- dione (CNQX) significantly reduced auditory-evoked spikes at all sites in these two subdivisions, and completely eliminated responses at many locations. This suggests that excitatory amino acid receptors mediate the bulk, if not all, of auditory responses in the ICx and lateral shell. NMDA and non-NMDA receptors contributed differently to auditory responses in the two subdivisions. In the ICx, AP5 significantly reduced the number of auditory-evoked spikes at every site tested. On average, AP5 eliminated 55% of auditory-evoked spikes at multiunit sites and 64% at single-unit sites in this structure. In contrast, in the lateral shell, AP5 significantly reduced responses at less than half the sites tested, and, on average, AP5 eliminated only 19% of spikes at multiunit sites and 25% at single-unit sites. When the magnitude of response blockade produced by AP5 at individual multiunit sites was normalized to adjust for site-to-site differences in the efficacy of iontophoresed AP5 and CNQX, AP5 blockade was still significantly greater in the ICx than the lateral shell. CNQX application strongly reduced responses in both subdivisions. These data suggest that NMDA receptor currents make a major contribution to auditory responses in the ICx, while they make only a small contribution to auditory responses in the lateral shell. Non-NMDA receptor currents, on the other hand, contribute to auditory responses in both subdivisions, and mediate the bulk of auditory transmission in the lateral shell. The time course of the NMDA receptor contribution to ICx auditory responses and the dependence of this contribution on stimulus level were both examined in detail. AP5 preferentially blocked spikes late in ICx auditory responses, while CNQX blocked spikes equally throughout the responses. This pattern is consistent with a simple model in which slow NMDA receptor currents and faster non-NMDA receptor currents are both activated by auditory inputs to ICx neurons.

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“…A number of studies have shown, in both the pigeon and chick, that glutamate is a excitatory transmitter in the tectorotundal projection and ␥-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in SP/IPS-Rt projection (Mitsacos et al, 1990;Ngo et al, 1992;Gao et al, 1995). Thus, according to the distribution of projections reported by Benowitz and Karten (1976) in the pigeon, the GABAergic fibres should terminate in the ventral Rt, and the glutamatergic fibres should terminate in the other parts of the Rt.…”

Section: Topographical Organisation and Functional Considerationsmentioning

confidence: 99%

Organisation of the tectorotundal and SP/IPS‐rotundal projections in the chick

Deng

Rogers

1998

J. Comp. Neurol.

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The organisation of the neural projections from the optic tectum and pretectal nuclei complex, n. subpretectalis / n. interstitio-pretecto-subpretectalis (SP/IPS), to the nucleus rotundus (Rt) in chicks was studied by using retrograde tracing techniques. After the injection of fluorescent retrograde tracers, rhodamine-conjugated latex microspheres, fluorescein-conjugated latex microspheres, True Blue, Fluoro-Gold, or rhodamine B isothiocyanate, into different regions of Rt and its middorsal extension, the nucleus triangularis (T), the distribution of retrogradely labelled neuronal cell bodies in the tectum and pretectal nuclei was assessed. Both the ipsilateral and contralateral tectorotundal projections were found to be organised topographically in as much as different sublaminas of the stratum griseum centrale (SGC) project in an orderly manner to Rt and T. The deepest stratum of SGC overlapping into the stratum album centrale projects to T. Deep SGC projects to the dorsal Rt and superficial SGC to the ventral Rt. A band running through the centre of Rt receives input from the central sublamina of SGC, and the caudal central Rt receives input from a deeper sublamina than does the rostral central Rt. The SP/IPS projects to the ipsilateral Rt only and the projection order is dorsal SP to dorsal Rt, ventral SP to ventral Rt and middle SP to the central band of Rt. The neurones in IPS and the nucleus of the tractus tectothalamicus project to T. Thus, Rt and T receive topographically both tecto- (excitatory) and SP/IPS- (inhibitory) projections. The possible functional implications for parallel information processing in these projections are discussed.

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Localization ofl-glutamate binding sites in chick brain by quantitative autoradiography

Cited by 19 publications

References 29 publications

Quantitative autoradiographic study of L‐glutamate binding sites in normal and atrophic human cerebellum

Quantitative autoradiographic study of L‐glutamate binding sites in normal and atrophic human cerebellum

NMDA and non-NMDA glutamate receptors in auditory transmission in the barn owl inferior colliculus

Organisation of the tectorotundal and SP/IPS‐rotundal projections in the chick

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