Chapter 7 Compartmentalised distribution of GABAA and glutamate receptors in relation to transmitter release sites on the surface of cerebellar neurones

Abstract

This chapter focuses on compartmentalized distribution of gamma-aminobutyric acid (GABA A ) and glutamate receptors in relation to transmitter release sites on the surface of cerebellar neurones. In theory, electron microscopic immunocytochemistry should have the resolution to localize receptors at synaptic and non-synaptic sites. Electron-dense, peroxidase reaction end-product has been found on synaptic specializations for AMPA, NMDA, metabotropic glutamate, and GABA A receptors; it is generally interpreted as visualizing synaptic receptors. The most direct support for a possible enrichment of GABA and AMPA receptors at synaptic sites came from the results of experiments using immunofluorescence labelling and confocal laser microscopy, showing intense immunoreactive spots on the surface of cultured hippocampal, spinal cord, and cerebellar neurones. It is demonstrated that nerve cells are able to express receptor proteins at different concentrations on their surface, and distinct GABA receptor subunits are differentially targeted to synapses on the surface of the same type of neurone.