Purkinje cells AMPA receptors

Brorson J. R., Manzolillo P. A., and Miller R. J. (1994). Ca2+entry via AMPA/KA receptor and excitotoxicity in cultured cerebellar Purkinje cells. J. Neurosci. 14 187-197. 

Tatsukawa T., Chimura T., Miyakawa H., and Yamaguchi K. (2006). Involvement of basal protein kinase C and extracellular signal-regulated kinase 1/2 activities in constitutive internalization of AMPA receptors in cerebellar Purkinje cells. J. Neurosci. 26 4820 4825. 

The climbing fibers are now believed to use glutamate as transmitter, like the major proportion of mossy fibers. They are strongly enriched in glutamate (Ottersen et al., 1992) and their terminals are apposed to Purkinje cell thorns that exhibit a high density of AMPA receptors (Landsend et al., 1997). 

Purkinje cells express GluR-A flop, GluR-B flip and flop, and GluR-C flip mRNAs GluR-A expression is the weakest (Keinanen et al., 1990 Sommer et al., 1990 Monyer et al., 1991 Sato et al., 1993 see Fig. II-L for pan GluR-A to -D expression). There are thus probably multiple AMPA receptors on Purkinje cells for example, these could be differentially located at parallel fibre and climbing fibre synapses. 

Fig. 6. Summary histogram of development of glutamate receptors at parallel [postnatal day 10 (PI0) to adult] and climbing (P2 to adult) fiber synapses on Purkinje cells of the cerebellum. Note especially the peak in immunogold labeling of the delta receptors at PI0-PI4 in climbing fiber synapses (cO, the peaks of the AMPA receptors (GluR2, GluR2/3 antibodies) at P2-P5, and the inverse patterns of peaks for parallel fiber synapses (pf) and climbing fiber synapses in adults for AMPA versus delta receptors. Modified from Zhao et al. (1998).

Fig. 48. Electron micrograph of the synaptic distribution of immunoreactivity for the GluRl subunit of the AMPA receptor in rat cerebellum as detected by an antibody against the carboxy-terminal (intracellular) region of GluRl. A. A spine (s) emerging from a Purkinje cell dendrite (Pd) establishes an immunopositive type 1 synapse (solid arrows) with a parallel fiber terminal (pft). Intra-cellular immunoreactivity is present inside Bergmann glial cell processes along dendritic elements (e.g., open arrow). B. The peroxidase reaction end-product labels the postsynaptic density (psd) at the intracellular face of the postsynaptic membrane (pom) and not the synaptic cleft between the presyaptic (pem) and postsynaptic (pom) membranes. Scale bars in A = 0.5 /xm, in B = 0.1 jum. Baude et al. (1994).

Purkinje cells express GluRl-flip, GluR2-flip and -flop, and GluR3-flip mRNA (Lambolez et al., 1992) that form AMPA receptors with desensitization time constants... 

Lambolez B, Audinat E, Bochet P, Crepel F. Rossier J (1992) AMPA receptor subunits expressed by single Purkinje-cells. Neuron. 9, 247-258. 

Nakazawa, K., Mikawa, S., Hashikawa, T., and Ito, M. (1995). Transient and persistent phosphorylation of AMPA-type glutamate receptor subunits in cerebellar Purkinje cells. Neuron 15, 697-709. 

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