Get access

Distribution and pharmacology of alanine–serine–cysteine transporter 1 (asc-1) in rodent brain

Authors

  • Lone Helboe,

    1. H. Lundbeck A/S, Biological Research, Departments of 1Molecular Disease Biology, 2Molecular Genetics and 4Molecular Pharmacology, Ottiliavej 9, DK-2500 Valby, Denmark
      3Department of Medical Anatomy, Panum Institute, University of Copenhagen, Denmark
    Search for more papers by this author
  • 1 Jan Egebjerg,

    1. H. Lundbeck A/S, Biological Research, Departments of 1Molecular Disease Biology, 2Molecular Genetics and 4Molecular Pharmacology, Ottiliavej 9, DK-2500 Valby, Denmark
      3Department of Medical Anatomy, Panum Institute, University of Copenhagen, Denmark
    Search for more papers by this author
  • 2 Morten Møller,

    1. H. Lundbeck A/S, Biological Research, Departments of 1Molecular Disease Biology, 2Molecular Genetics and 4Molecular Pharmacology, Ottiliavej 9, DK-2500 Valby, Denmark
      3Department of Medical Anatomy, Panum Institute, University of Copenhagen, Denmark
    Search for more papers by this author
  • and 3 Christian Thomsen 4

    1. H. Lundbeck A/S, Biological Research, Departments of 1Molecular Disease Biology, 2Molecular Genetics and 4Molecular Pharmacology, Ottiliavej 9, DK-2500 Valby, Denmark
      3Department of Medical Anatomy, Panum Institute, University of Copenhagen, Denmark
    Search for more papers by this author

: Dr Christian Thomsen, as above.
E-mail: ctho@lundbeck.com

Abstract

A polyclonal antibody against the Na+-independent alanine–serine–cysteine transporter 1 (asc-1) was raised and the specificity of the antibody verified by Western blots performed on membranes prepared from HEK293 cells transiently transfected with the cloned murine asc-1. The antibody was then used to localize the transporter in the brain of two rodent species by using immunohistochemistry at the light and electron microscopical level. asc-1-immunoreactivity (asc-1-ir) was widely distributed throughout the mouse and rat brain. Areas with high levels of asc-1-ir included hypothalamus, the medial septal area, globus pallidus, entopeduncular nucleus, cingulate and retrosplenial cortices. Moderate asc-1-ir was observed in several areas including layers III and V of the neocortex, thalamus, nucleus accumbens, caudate putamen, bed nucleus of stria terminalis, all amygdaloid nuclei, hippocampus (CA1–CA3 and hilus of the dentate gyrus), as well as several brainstem nuclei. asc-1-ir was observed as punctuate staining consistent with varicosities matching neuronal cell bodies and dendritic fields. At the ultrastructural level, asc-1-ir was mainly confined to presynaptic terminals. Immunostaining in either glial cell bodies or perivascular sites was not observed and white matter was completely devoid of asc-1-ir. Furthermore, the pharmacology of the Na+-independent uptake site for [3H]d-serine in rat brain synaptosomal P2 fractions was compared with the substrate specificity of the cloned human asc-1 transporter and a high degree of correlation was demonstrated. We conclude that asc-1-ir is widespread in the brain and limited to neuronal structures and that asc-1 may contribute to synaptic clearance of d-serine in brain.

Ancillary