Elsevier

Neuroscience

Volume 105, Issue 2, 27 July 2001, Pages 509-520
Neuroscience

Immunohistochemical localization of group I and II metabotropic glutamate receptors in control and amyotrophic lateral sclerosis human spinal cord: upregulation in reactive astrocytes

https://doi.org/10.1016/S0306-4522(01)00181-6Get rights and content

Abstract

Excitotoxicity, which is mediated by the excessive activation of glutamate receptors, has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). There is substantial information about the distribution and function of ionotropic glutamate receptors in the spinal cord, although the role of metabotropic glutamate receptors (mGluRs) is poorly understood in this region of the brain, particularly under pathological conditions. We used immunocytochemistry to study the general distribution of group I and group II mGluR immunoreactivity in the human spinal cord, as well as the cell-specific expression of these receptors. We also investigated whether mGluR expression was altered in the spinal cord of patients with sporadic and familial ALS. Immunocytochemical analysis of control human spinal cord demonstrated that mGluR1α and mGluR5 (group I mGluRs) were highly represented in neuronal cells throughout the spinal cord. mGluR1α showed the highest relative level of expression in ventral horn neurons (laminae VIII and IX), whereas intense mGluR5 immunoreactivity was observed within the dorsal horn (superficial laminae I and II). Group II mGluRs (mGluR2/3) immunoreactivity was mainly concentrated in the inner part of the lamina II. With respect to specific neuronal populations, mGluR2/3 and mGluR5 appeared to be most frequently expressed in calbindin-containing and calretinin-containing cells, respectively. In control spinal cord only sparse astrocytes showed a weak to moderate mGluR immunoreactivity. Regional differences in immunoreactivity were apparent in ALS compared to control. In particular, mGluR expression was increased in reactive glial cells in both gray (ventral horn) and white matter of ALS spinal cord.

Upregulation of mGluRs in reactive astrocytes may represent a critical mechanism for modulation of glial function and changes in glial–neuronal communication in the course of neurodegenerative diseases.

Section snippets

Subjects

The spinal cords of 25 patients (selected from the Netherlands ALS tissue bank) were studied. Tissue was obtained and used in a manner compliant with the Declaration of Helsinki. Informed consent was obtained for the use of brain tissue. The clinical (derived from patients’ medical records) and neuropathological features are summarized in Table 1. Seventeen patients had a clinical and post-mortem neuropathological diagnosis of ALS (12 sporadic, sALS, and five familial type of ALS, FALS). All

Case material

The clinical and neuropathological characteristics of the subjects used in this study are summarized in Table 1. There were no significant differences between the two groups (ALS and normal controls) with respect to the variables of age, sex, post-mortem interval or storage duration (Mann–Whitney two-tailed U-test). None of the control patients had confounding neurological or neuropathological abnormalities that would be expected to interfere with our analysis of the spinal cord.

mGluR expression in human spinal cord

The patterns of

Discussion

The present study describes the regional and cellular distribution of group I and group II mGluR subtypes in normal and ALS spinal cord. The following observations were made. (1) Immunocytochemical analysis demonstrated expression of mGluR1α, mGluR5 and mGluR2/3 throughout the human spinal cord. mGluR1α showed the highest relative level of expression in ventral horn neurons (laminae VIII and IX), whereas intense mGluR5 immunoreactivity was observed within the dorsal horn (superficial laminae I

Acknowledgements

This work was supported by Telethon Italy Grant 1244 (M.V.C.) and Teding van Berkhout Fellowship of De Christelijke Vereniging voor de Verpleging van Lijders aan Epilepsie (E.A.) and Netherlands ALS Research Foundation (D.T.). We thank W.P. Meun and R. Visser for expert photography.

References (70)

  • C Nathan et al.

    Nitric oxide synthases: roles, tolls, and controls

    Cell

    (1994)
  • F Nicoletti et al.

    Group-I metabotropic glutamate receptors: hypotheses to explain their dual role in neurotoxicity and neuroprotection

    Neuropharmacology

    (1999)
  • H Ohishi et al.

    Distribution of a metabotropic glutamate receptor, mGluR2, in the central nervous system of the rat and mouse: an immunohistochemical study with a monoclonal antibody

    Neurosci. Res.

    (1998)
  • S.A O’Reilly et al.

    Motor neuron–astrocyte interactions and levels of Cu, Zn superoxide dismutase in sporadic amyotrophic lateral sclerosis

    Exp. Neurol.

    (1995)
  • R.S Petralia et al.

    The metabotropic glutamate receptors, mGluR2 and mGluR3, show unique postsynaptic, presynaptic and glial localizations

    Neuroscience

    (1996)
  • J.P Pin et al.

    The metabotropic glutamate receptors: structure and functions

    Neuropharmacology

    (1995)
  • D Schiffer et al.

    Reactive astrogliosis of the spinal cord in amyotrophic lateral sclerosis

    Neurol. Sci.

    (1996)
  • D.D Schoepp et al.

    Pharmacological agents acting at subtypes of metabotropic glutamate receptors

    Neuropharmacology

    (1999)
  • G.A Silva et al.

    Group I and II metabotropic glutamate receptor expression in cultured rat spinal cord astrocytes

    Neurosci. Lett.

    (1999)
  • P.K Smith et al.

    Measurement of protein using bicinchoninic acid

    Anal. Biochem.

    (1985)
  • F.R Tang et al.

    Metabotropic glutamate receptor subtype-1 alpha (mGluR1 alpha) immunoreactivity in ependymal cells of the rat caudal medulla oblongata and spinal cord

    Neurosci. Lett.

    (1997)
  • F.R Tang et al.

    Pre- and/or post-synaptic localisation of metabotropic glutamate receptor 1alpha (mGluR1alpha) and 2/3 (mGluR2/3) in the rat spinal cord

    Neurosci. Res.

    (1999)
  • S.K Agrawal et al.

    Role of group I metabotropic glutamate receptors in traumatic spinal cord white matter injury

    J. Neurotrauma

    (1998)
  • M.E Alexianu et al.

    The role of calcium-binding proteins in selective motoneuron vulnerability in amyotrophic lateral sclerosis

    Ann. Neurol.

    (1994)
  • J.W Allen et al.

    Group II metabotropic glutamate receptor activation attenuates traumatic neuronal injury and improves neurological recovery after traumatic brain injury

    J. Pharmacol. Exp. Ther.

    (1999)
  • F.J Alvarez et al.

    Differential distribution of metabotropic glutamate receptors 1a, 1b, and 5 in the rat spinal cord

    J. Comp. Neurol.

    (2000)
  • J.M Anneser et al.

    Activation of metabotropic glutamate receptors delays apoptosis of chick embryonic motor neurons in vitro

    NeuroReport

    (1998)
  • M Antal et al.

    Calcium-binding proteins, parvalbumin- and calbindin-D 28k-immunoreactive neurons in the rat spinal cord and dorsal root ganglia: a light and electron microscopic study

    J. Comp. Neurol.

    (1990)
  • Aronica, E., Leenstra, S., Jansen, G., van Veelen, C.W., Yankaya, B., Troost, D., 2001. Expression of BDNF and tyrosine...
  • E Aronica et al.

    Upregulation of metabotropic glutamate receptor subtype mGluR3 and mGluR5 in reactive astrocytes in a rat model of mesial temporal lobe epilepsy

    Eur. J. Neurosci.

    (2000)
  • Aronica, E., Yankaya, B, Jansen, G.H., Leenstra, S., van Veelen, C.W.M., Gorter, J.A., Troost, D., Ionotropic and...
  • K Biber et al.

    Expression and signaling of group I metabotrophic glutamate receptors in astrocytes and microglia

    J. Neurochem.

    (1999)
  • S.J Boxall et al.

    Enhanced expression of metabotropic glutamate receptor 3 messenger RNA in the rat spinal cord during ultraviolet irradiation induced peripheral inflammation

    Neuroscience

    (1998)
  • V Bruno et al.

    Neuroprotection by glial metabotropic glutamate receptors is mediated by transforming growth factor-beta

    J. Neurosci.

    (1998)
  • V Bruno et al.

    Metabotropic glutamate receptors and neuronal degeneration in culture

    Adv. Neurol.

    (1996)
  • Cited by (0)

    1

    The first two authors contributed equally to the present work.

    View full text