AMPA receptors retina

Ferreira, I.L., Duarte, C.B., and Carvalho, A.P. 1998. Kainate-induced retina amacrine-like cell damage is mediated by AMPA receptors. Neuroreport 9, 3471—3475. 

Physiological studies have identified both post- and presynaptic roles for ionotropic kainate receptors. Kainate receptors contribute to excitatory post-synaptic currents in many regions of the CNS including hippocampus, cortex, spinal cord and retina. In some cases, postsynaptic kainate receptors are codistributed with AMPA and NMDA receptors, but there are also synapses where transmission is mediated exclusively by postsynaptic kainate receptors for example, in the retina at connections made by cones onto off bipolar cells. Extrasynaptically located postsynaptic kainate receptors are most likely activated by spill-over glutamate (Eder et al. 2003). Modulation of transmitter release by presynaptic kainate receptors can occur at both excitatory and inhibitory synapses. The depolarization of nerve terminals by current flow through ionotropic kainate receptors appears sufficient to account for most examples of presynaptic regulation however, a number of studies have provided evidence for metabotropic effects on transmitter release that can be initiated by activation of kainate receptors. The hyperexcitability evoked by locally applied kainate, which is quite effectively reduced by endocannabinoids, is probably mediated preferentially via an activation of postsynaptic kainate receptors (Marsicano et al. 2003). 

Szikra, T, and Witkovsky, P. 2001. Contributions of AMPA- and kainate-sensitive receptors to the photopic electroretinogram of the Xenopus retina. Vis Neurosci 18, 187-196. 

Retinal ganglion cells are the output cells of the retina. Their axons course along the vitreal surface of the retina and bundle together to exit the eye as the optic nerve. Ganglion cells are excited by glutamate released from bipolar cells acting on both NMDA and non-NMDA (KA- and AMPA-type) glutamate receptors (Thoreson and Witkovsky, 1999). 

Fig. 10. The cell types in the rat retina and their expression of the AMPA, NMDA and kainate receptor subunit mRNAs (circuit diagram adapted from Barnstable, 1993 Bahn and Wisden, 1997). The assignment of subunit groupings to different cell classes does not imply that, for example, all amacrine cells co-express all the listed subunits subsets of amacrine cells, horizontal or ganglion cells express different subunit combinations (see text).

Qin P, Pourcho RG (1999) Localization of AMPA-selective glutamate receptor subunits in the cat retina a light-and electron-microscopic study. Vis Neurosci 76 169-177. 

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