AMPA receptors hippocampus

Kainate receptors mediate a depression of evoked excitatory synaptic transmission in areas CA1 (40,88-90) and CA3 (35,37,91,92) of the hippocampus. There is strong evidence that in area CA1 the locus of this effect is presynaptic. Thus, activation of kainate receptors depresses release of L-glutamate from synaptosomes (88) and depresses both NMDA and AMPA receptor-mediated components of the evoked EPSC in parallel (88,90). Furthermore, the effects of kainate receptor activation on excitatory synaptic transmission in CA1 are associated with changes in presynaptic Ca2+ (89), an increase in paired-pulse facilitation (35,88,89), and a reduction in quantal content, as assessed using 1/CV2, but no change in mEPSC amplitude (90). 

Regional distribution studies indicate that the highest density of kainate receptor occurs in the stratum lucidum of the hippocampus (mossy fiber system) and in the inner and outer layers of the neocortex. The highest density of NMDA receptors is found in the hippocampus, stratum radiatum, and in the striatum, thalamus, and cerebral cortex. The distribution of AMPA receptors is similar to that of NMDA receptors, but in the cerebellum AMPA receptors predominate in the molecular layer... 

Chabot C., Gagne J., Giguere C., Bernard J., Baudry M., and Massicotte G. (1998). Bidirectional modulation of AMPA receptor properties by exogenous phospholipase A2 in the hippocampus. Hippocampus 8 299-309. 

Menard C., Valastro B., Martel M. A., Chartier T., Marineau A., Baudry M., and Massicotte G. (2005). AMPA receptor phosphorylation is selectively regulated by constitutive phospholipase A2 and 5-lipoxygenase activities. Hippocampus 15 370-380. 

St-Gelais F., Menard C., Congar P., Tmdeau L. E., and Massicotte G. (2004). Postsynaptic injection of calcium-independent phospholipase A2 inhibitors selectively increases AMPA receptor-mediated synaptic transmission. Hippocampus 14 319-325. 

The expression of AMPA receptor interacting proteins has presently only been measured in three studies in the hippocampus. These studies find no changes in the expression of SAP-97, GRIP, NF-L, SAP-102, PSD95, and PSD93 in the hippocampus in schizophrenia (Toyooka et al., 2002 Toro and Deakin, 2005 McCullumsmith et al., 2007). 

Nusser Z, Lujan R, Laube G, Roberts JD, Molnar E, Somogyi P (1998) CeU type and pathway dependence of synaptic AMPA receptor number and variability in the hippocampus. Neuron 21 545-559... 

Mitani H, Shirayama Y, Yamada T, Maeda K, Ashby CR, Kawa-hara R. Correlation between plasma levels of glutamate, alanine, and serine with severity of depression. Progr. Neuro-Psycho-pharmacol. Biol. Psychiatry 2006 30 1155-1158. Martinez-Turrillas R, Erechilla D, Del Rio J. Chronic antidepressant treatment increases the membrane expression of AMPA receptors in rat hippocampus. Neuropharmacology 2002 43 1230-1237. Petty E. GABA and mood disorders a brief review and hypothesis. J. Affec. Disorders 1995 34 275-281. 

Bai F, Bergeron M, Nelson DL (2003) Clir onic AMPA receptor potendator (LY451646) ti eatment mcreases cell proliferadon in adult rat hippocampus. Neur opharmacology 44 1013—1021. 

Fig. 17. Drawings showing the relative expression levels of AMPA receptor subunit GluR-A to -D mRNAs in parvalbumin- (PV) and calretinin- (CR) immunopositive cells of the adult rat hippocampus (non-radioactive in situ hybridization combined with indirect fluorescence immunocytochemistry). Each dot represents one cell. Intensity levels are black, strongly positive grey, moderate or lightly labelled white, negative (Catania et al., 1998).

Catania MV, Tolle T, Seeburg PH, Monyer H (1995) Differential expression of AMPA receptor subunits in NOS-positive neurons of cortex, striatum and hippocampus. J Neurosci 75 7046-7061. 

Catania MV, Bellomo M, Giuffrida R, Giuffrida Stella AM, Albanese V (1998) AMPA receptor subunits are differentially expressed in parvalbumin- and calretinin-positive neurons of the rat hippocampus. Eur J Neurosci 70 3479-3490. 

Gold SJ, Hennegriff M, Lynch G, Gall CM (1996) Relative concentrations and seizure-induced changes in mRNAs encoding three AMPA receptor subunits in hippocampus and cortex. J Comp Neurol 365 541-555. 

In addition, some synapses in the hippocampus and other regions may have NMDA receptors but lack AMPA receptors, while most synapses on the same neurons have both NMDA and AMPA receptors. The former synapses are called silent synapses and can acquire AMPA receptors following adequate activation (e.g., review by Malenka and Nicoll, 1997 Nusser et al., 1998 Petralia et al., 1999a Shi et al., 1999) (see Section 3.1.2). 

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