Enrichment of glutamate immunoreactivity in lemniscal terminals in the ventropostero lateral thalamic nucleus of the rat: An immunogold and WGA‐HRP study

Biasi, S. De; Amadeo, Alida; Spreafico, Roberto; Rustioni, Aldo

doi:10.1002/ar.1092400114

Cited by 40 publications

(13 citation statements)

References 34 publications

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“…In particular, in neonatal VB the ascending terminals were not distinguishable from terminals of other sources as they are in adults De Biasi et al 1988, 1994a. Previous light microscopic tracing studies reported that, by the day of 351 birth, ascending fibers have already reached their thalamic target, where they ramify extensively (Belford and Killakey 1982;Asanuma et al 1988).…”

Section: Discussionmentioning

confidence: 99%

“…The centers related to the visual pathways are among the areas that have been more extensively investigated (Wienfield and Powell 1980;Mason 1982;Campbell et al 1984;Holstein et al 1985;Weber and Kalil 1987;Campbell and Shatz 1992;Khan et al 1994), whereas relatively little information is available on the postnatal development and differentiation of two of the thalamic nuclei involved in the processing of somatosensory inputs, i.e., the VB and Rt nuclei. These nuclei represent a convenient model system because their synaptic circuitry and neurochemical content have been extensively investigated in the adult and in rats it has been shown that they have a much simpler organization than in other mammals (McAllister and Wells 1981;Lieberman 1981, 1985;De Biasi et al 1986, 1994aMa et al 1987;Rustioni et al 1988;Rustioni and Weinberg 1989;De Biasi and Rustioni 1990).…”

Section: Introductionmentioning

confidence: 99%

“…VB receives excitatory inputs mainly from cortical and ascending (lemniscal and spinothalamic) afferents and inhibitory (GABAergic) inputs from the adjacent Rt nucleus (Jones 1985;De Biasi et al 1988, 1994aMa et al 1987;Rustioni and Weinberg 1989;De Biasi and Rustioni 1990). At the electron microscopic level the terminals of these afferent pathways are morphologically identifiable due to their different ultrastructural characteristics and neurochemical content (McAllister and Wells 1981;Ma et al 1987;De Biasi et al 1988, 1994a.…”

Section: Introductionmentioning

confidence: 99%

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Ultrastructural characterization of the postnatal development of the thalamic ventrobasal and reticular nuclei in the rat

et al. 1996

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Electron microscopy has been employed to analyze the normal maturational sequence that characterizes the postnatal development of synaptic circuits in the ventrobasal (VB) and reticular (Rt) thalamic nuclei of rats at different ages (from birth to the end of the third postnatal week). Throughout the first postnatal week, similar signs of immaturity are observed in both nuclei, mainly consisting in scarcity of cytoplasmic organelles, presence of wide extracellular spaces, and absence of myelinated fibers. Several synaptic terminals are however present from birth, thus indicating that some of the afferents have already reached and contacted their thalamic target during embryonic life. Most of the terminals are small and contain only a few round, clear vesicles, and therefore their cytological features do not allow the identification of their origin. In particular, in both nuclei, terminals with flat vesicles and symmetric specialization are only rarely observed, and in VB the ascending terminals are not distinguishable from terminals of other sources as they are in adults. During the second postnatal week, progressive maturational changes in VB and Rt lead to neurons having well-developed cytoplasmic organelles and to an elaborate neuropil containing myelinated fibers and synaptic terminals that are morphologically heterogeneous and resemble the adult ones. The permanence of growth cone-like profiles and of numerous somatic and dendritic protrusions, often contacted by synaptic terminals, indicates that a certain degree of reorganization is still taking place in both nuclei. By the end of the third postnatal week the synaptic organization of VB and Rt is indistinguishable from that observed in adults. This ultrastructural study shows that the appearance of the neuropil of VB and Rt and the morphological complexity of the synaptic arrangements characteristic of the adult rat are not present in neonates, but are gradually acquired during the first three postnatal weeks, and that they result from progressive modifications in circuit organization involving both pre- and postsynaptic elements.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultrastructural characterization of the postnatal development of the thalamic ventrobasal and reticular nuclei in the rat

et al. 1996

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“…Numerous early studies demonstrated that glutamate is the neurotransmitter of all these excitatory thalamic inputs (Haldeman and McLennan, 1972;de Biasi et al, 1994; reviewed by Salt and Eaton, 1996). Recent neuropharmacological findings have shown that the ascending excitatory afferents to both the ventral posterior and lateral geniculate nuclei (LGN) elicit responses in relay neurons that are sensitive to both non-N-methyl-D-aspartate (NMDA) and NMDA receptor antagonists.…”

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confidence: 99%

Subcellular distribution of AMPA and NMDA receptor subunit immunoreactivity in ventral posterior and reticular nuclei of rat and cat thalamus

Liu

1997

J. Comp. Neurol.

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Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) selective glutamate receptors mediate excitatory neurotransmission in the somatosensory thalamus, but morphological localization of the receptors at identified thalamic synapses has been lacking. The authors used electron microscopic immunocytochemistry to localize AMPA selective GluR 2/3 subunits (GluR2/3) and NMDA receptor subunit 1 (NMDAR1) in rat and cat ventral posterior lateral nucleus (VPL) and in the associated sector of the reticular nucleus (RTN). Light microscopy showed that GluR2/3 and NMDAR1 immunolabeled neurons are homogeneously distributed in both nuclei. The relationship between glutamate receptor labeled profiles and glutamate or gamma-aminobutyric acid (GABA) labeled synapses was revealed by combining preembedding and postembedding immunostaining at the electron microscopic level. GluR2/3 and NMDAR1 immunoreactivity was located in somata and in proximal and distal dendrites of VPL relay cells and of RTN cells. Immunoreactivity was concentrated in postsynaptic densities of glutamatergic synapses and absent from postsynaptic densities of GABAergic synapses. In the cat, GluR2/3 and NMDAR1 immunoreactivity was also localized in GABAergic interneurons, including their presynaptic dendrites (PSD). Of the GluR2/3 and NMDAR1 labeled thalamic synapses observed, 10-29% were lemniscal (RL) type synapses in VPL; 60-70% were corticothalamic (RS) type synapses in the VPL and RTN. In the cat, 7-19% were identified as PSD profiles, and more NMDAR1 labeled PSD were found in the VPL than in the RTN. The main findings were as follows: 1) AMPA selective GluR2/3 and NMDAR1 share similar distribution patterns in the rat and cat somatosensory thalamus, 2) both glutamate receptors are likely to be colocalized at postsynaptic densities of both RL and RS synapses, and 3) localization of the glutamate receptor proteins in GABAergic dendrites in the cat thalamus indicates that glutamatergic transmission to GABAergic neurons is also mediated by both NMDA and non-NMDA receptors.

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“…The specificity of the antisera against PV and GABA has been previously characterized (Celio, 1990;De Biasi et al, 1994). Method specificity both for PV and GABA immunolabelling was controlled by the application of rabbit nonimmune serum as well as by the processing of a series of sections omitting various stages from the regular staining sequence.…”

Section: Immunocytochemical Controlsmentioning

confidence: 99%

Immunocytochemical and ultrastructural study of the rat perireticular thalamic nucleus during postnatal development

et al. 1998

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The perireticular thalamic nucleus (PRT) consists of scattered neurons that are located in the internal capsule adjacent to the gamma aminobutyric acid (GABA)-immunoreactive (ir) reticular thalamic nucleus (RT) and whose number decreases during development. The common feature of PRT neurons in different species is the immunoreactivity for the calcium binding protein parvalbumin (PV), which is also expressed by RT cells. In this study, we analyzed, at the light and electron microscopic level, the distribution and morphology of PV-ir neurons and their relationship with GABA in adult and developing rats. We found that the rostrocaudal distribution and the morphology of PV-ir neurons of the PRT were different at each stage of postnatal development examined. The adult configuration of the PV-ir population in the PRT was achieved at postnatal day 21. With electron microscopy, the developing PRT was observed to contain PV-ir neuronal cell bodies and dendrites contacted by several PV-negative synaptic terminals, some of which were GABA-ir, whereas the adult PRT contained also large PV-ir boutons, generally GABA-ir. Very few GABA-ir neurons were found in the PRT region and only during the first postnatal week, thus indicating that the PV-ir neurons of PRT represent a distinct population from those of RT. Our results demonstrate a morphological, neurochemical, and ultrastructural complexity of the PRT not only during development, but also in adulthood. These findings provide new data supporting the suggested roles of the PRT during postnatal development, and may indicate that in adult life it can play other so far unknown functions.

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Enrichment of glutamate immunoreactivity in lemniscal terminals in the ventropostero lateral thalamic nucleus of the rat: An immunogold and WGA‐HRP study

Abstract: These findings are in agreement with several lines of evidence, obtained with different experimental approaches, supporting the hypothesis that Glu plays a major role in conveying sensory stimuli to the thalamus from second order neurons in the dorsal column nuclei.

Cited by 40 publications

References 34 publications

Ultrastructural characterization of the postnatal development of the thalamic ventrobasal and reticular nuclei in the rat

Ultrastructural characterization of the postnatal development of the thalamic ventrobasal and reticular nuclei in the rat

Subcellular distribution of AMPA and NMDA receptor subunit immunoreactivity in ventral posterior and reticular nuclei of rat and cat thalamus

Immunocytochemical and ultrastructural study of the rat perireticular thalamic nucleus during postnatal development

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