题名：Diversity of glycine receptors in the mouse retina: Localization of the alpha4 subunit.
作者：Heinze L, Harvey RJ, Haverkamp S, Wassle H.
来源：J Comp Neurol. 2007 Feb 1;500(4):693-707.
摘要：Liane Heinze 1, Robert J. Harvey 2, Silke Haverkamp 1, Heinz W?ssle 1 *
1Department of Neuroanatomy, Max-Planck-Institute for Brain Research, D-60528 Frankfurt/Main, Germany
2Department of Pharmacology, School of Pharmacy, London WC1N 1AX, United Kingdom
email: Heinz W?ssle (email@example.com)
*Correspondence to Heinz W?ssle, Max-Planck-Institute f. Hirnforschung, Neuroanatomie, Deutschordenstr. 46, D-60528, Frankfurt/Main, Germany
Medical Research Council; Grant Number: G0500833
Glycine and -aminobutyric acid (GABA) are the major inhibitory neurotransmitters in the retina. Approximately half of the amacrine cells release glycine at their synapses with bipolar, other amacrine, and ganglion cells. Whereas the retinal distributions of glycine receptor (GlyR) subunits 1, 2, and 3 have been mapped, the role of the 4 subunit in retinal circuitry remains unclear. A rabbit polyclonal antiserum was raised against a peptide that comprises the C-terminal 14 amino acids of the mouse GlyR 4 subunit. Using immunocytochemistry, we localized the 4 subunit in the inner plexiform layer (IPL) in brightly fluorescent puncta, which represent postsynaptically clustered GlyRs. This was shown by double-labeling sections for GlyR 4 and synaptic markers (bassoon, gephyrin). Double-labeling sections for GlyR 4 and the other GlyR subunits shows that they are mostly clustered at different synapses; however, 30% of the 4-containing synapses also express the 2 subunit. We also studied the pre- and postsynaptic partners at GlyR 4-containing synapses and found that displaced (ON-) cholinergic amacrine cells prominently expressed the 4 subunit. The density of GlyR 4-expressing synapses in wildtype, Glra1ot/ot, and Glra3-/- mouse retinas did not differ significantly. Thus, there is no apparent compensation of the loss of 1 or 3 subunits by an upregulation of 4 subunit gene expression; however, the 2 subunit is moderately upregulated. J. Comp. Neurol. 500:693-707, 2007. ? 2006 Wiley-Liss, Inc.