P2Y1receptor switches to neurons from glia in juvenile versus neonatal rat cerebellar cortex

Susanna Amadio,Fabrizio Vacca,Alessandro Martorana,Cinzia Volonté,Giuseppe Sancesario

doi:10.1186/1471-213x-7-77

Abstract

BackgroundIn the CNS, several P2 receptors for extracellular nucleotides are identified on neurons and glial cells to participate to neuron-neuron, glia-glia and glia-neuron communication.ResultsIn this work, we describe the cellular and subcellular presence of metabotropic P2Y1 receptor in rat cerebellum at two distinct developmental ages, by means of immunofluorescence-confocal and electron microscopy as well as western blotting and direct membrane separation techniques. At postnatal day 21, we find that P2Y1 receptor in addition to Purkinje neurons, is abundant on neuronal specializations identified as noradrenergic by anatomical, morphological and biochemical features. P2Y1 receptor immunoreactivity colocalizes with dopamine β-hydroxylase, tyrosine hydroxylase, neurofilament light chain, synaptophysin and flotillin, but not with glial fibrillary acidic protein for astrocytes. P2Y1 receptor is found enriched in membrane microdomains such as lipid rafts, in cerebellar synaptic vesicles, and is moreover visualized on synaptic varicosities by electron microscopy analysis. When examined at postnatal day 7, P2Y1 receptor immunoreactivity is instead predominantly expressed only on Bergmann and astroglial cells, as shown by colocalization with glial fibrillary acidic protein rather then neuronal markers. At this age, we moreover identify that P2Y1 receptor-positive Bergmann fibers wrap up doublecortin-positive granule cells stretching along them, while migrating through the cerebellar layers.ConclusionMembrane components including purinergic receptors are already known to mediate cellular contact and aggregation in platelets. Our results suggesting a potential role for P2Y1 protein in cell junction/communication and development, are totally innovative for the CNS.

Highlights

In the CNS, several P2 receptors for extracellular nucleotides are identified on neurons and glial cells to participate to neuron-neuron, glia-glia and glia-neuron communication
P2Y1 receptor is present on tyrosine hydroxylase- and dopamine β-hydroxylase-positive neurons in juvenile rat cerebellum We describe in this work the topographic cellular and subcellular in vivo distribution of P2Y1 receptor protein in the cerebellum of juvenile rat at postnatal day 21 (P21)
We show by confocal microscopy that P2Y1 protein immunoreactivity is uniformly distributed throughout specific zones of cerebellar cortex (Fig. 1)

Summary

Introduction

In the CNS, several P2 receptors for extracellular nucleotides are identified on neurons and glial cells to participate to neuron-neuron, glia-glia and glia-neuron communication. Extracellular nucleotides partake to excitatory neurotransmission and neuromodulation in the CNS and are capable of intervening in a broad array of physiopathological functions acting on different P2 purinergic receptors [1,2,3]. Because of their heterogeneous faculty of responding to several diverse nucleotides, interest is growing on discovering the exact localization of the various P2 receptor subunits in selected organs, tissues and cellular phenotypes [4,5]. Among P2Y receptors, an elevated expression of the P2Y1 subtype was detected in both human [11] and rat brain [12]. P2Y1 receptor in rat is detected on grey matter, cerebellar, cortical and hippocampal neurons, and on white matter of corpus callosum and optic nerve [12]

Objectives

Methods

Results

Discussion

Conclusion