Postnatal development of alkaline phosphatase activity correlates with the maturation of neurotransmission in the cerebral cortex

Authors

  • Caroline Fonta,

    Corresponding author
    1. Cerveau et Cognition, Centre National de la Recherche Scientifique–Université Paul Sabatier UMR5549, Faculté de Médecine Rangueil, 31062 Toulouse Cedex, France
    • Cerveau et Cognition, CNRS-UPS UMR5549, Faculté de Médecine Rangueil, 133 route de Narbonne, 31062 Toulouse Cedex, France
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  • Laszlo Negyessy,

    1. Neurobiology Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest H-1094, Hungary
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  • Luc Renaud,

    1. Cerveau et Cognition, Centre National de la Recherche Scientifique–Université Paul Sabatier UMR5549, Faculté de Médecine Rangueil, 31062 Toulouse Cedex, France
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  • Pascal Barone

    1. Cerveau et Cognition, Centre National de la Recherche Scientifique–Université Paul Sabatier UMR5549, Faculté de Médecine Rangueil, 31062 Toulouse Cedex, France
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Abstract

We have shown previously that the tissue nonspecific alkaline phosphatase (TNAP) is selectively expressed in the synaptic cleft of sensory cortical areas in adult mammals and, by using sensory deprivation, that TNAP activity depends on thalamocortical activity. We further analyzed this structural functional relationship by comparing the developmental pattern of TNAP activity to the maturation of the thalamocortical afferents in the primate brain (Callithrix jacchus). Cortical expression of alkaline phosphatase (AP) activity reflects the sequential maturation of the modality-specific sensory areas. Within the visual cortex, the regional and laminar distribution of AP correlates with the differential maturation of the magno- and parvocellular streams. AP activity, which is transiently expressed in the white matter, exhibits a complementary distributional pattern with myelin staining. Ultrastructural analysis revealed that AP activity is localized exclusively to the myelin-free axonal segments, including the node of Ranvier. It was also found that AP activity is gradually expressed in parallel with the maturation of synaptic contacts in the neuropile. These data suggest the involvement of AP, in addition to neurotransmitter synthesis previously suggested in the adult, in synaptic stabilization and in myelin pattern formation and put forward a role of AP in cortical plasticity and brain disorders. J. Comp. Neurol. 486:179–196, 2005. © 2005 Wiley-Liss, Inc.

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