Disease relevance of Amacrine Cells

• Here we report that exogenous opiates affect both the release of GABA from GABAergic amacrine cells and the firing patterns of ganglion cells in the goldfish retina [1].
• These results suggest that contrast gain may be lowered in the peripheral retina in Parkinson's disease, perhaps because of an abnormality of dopamine amacrine cells, whose density peaks in the peripheral retina [2].
• CONCLUSIONS: There is damage to tyrosine hydroxylase-immunoreactive amacrine cells during fetal chronic placental insufficiency [3].
• Dose-dependent effects of 6-hydroxy dopamine on deprivation myopia, electroretinograms, and dopaminergic amacrine cells in chickens [4].
• The effect of LIM and lens-induced hyperopia (LIH) on the numbers of 5-HT-containing amacrine cells in the retina were then determined [5].

High impact information on Amacrine Cells

• During retinogenesis, Prox1 can be detected in differentiating horizontal, bipolar and AII amacrine cells [6].
• Surprisingly, we found that although some amacrine cells contain both enkephalin and GABA, others contain only one or the other [7].
• Co-localization of neurotensin-like immunoreactivity and 3H-glycine uptake system in sustained amacrine cells of turtle retina [8].
• Recently, in addition to conventional neurotransmitters such as acetylcholine, dopamine, glycine and gamma-aminobutyric acid (GABA), putative neuroactive peptide transmitters have been localized to specific retinal amacrine cells [1].
• Localisation of substance P immunoreactivity in amacrine cells of the retina [9].

Chemical compound and disease context of Amacrine Cells

• NO synthase immunoreactivity and NADPH diaphorase staining are colocalized in the pedunculopontine nucleus with choline acetyltransferase-containing cells and are also colocalized in amacrine cells of the inner nuclear layer and ganglion cells of the retina, myenteric plexus neurons of the intestine, and ganglion cells of the adrenal medulla [10].
• In other mammals, the light responses of polyaxonal amacrine cells like these and cholinergic amacrine cells have been recorded, and the effects of acetylcholine and cholecystokinin on ganglion cells are known [11].
• Inhibition of on-centre cells, thus, appears to be mediated by GABA, whereas that of off-centre cells, by glycine regardless of whether the cells are 'sustained' or 'transient'. Possible existence of GABAergic and glycinergic amacrine cells making postsynaptic contact with on-centre and off-centre ganglion cells, respectively, is proposed [12].
• This differential targeting of ganglion cells and amacrine cells in the OFF vs. ON layers indicates a difference in the role of bipolar cells in the generation of receptive field properties, depending on whether or not they use GABA as well as glutamate for their transmitter [13].
• In addition to the variable NMDA activation pattern, we found that virtually all ganglion cells (87%) showed NMDA-gated AGB entry, compared with only 58% of amacrine cells [14].

Biological context of Amacrine Cells

• These results suggest that the cholinergic amacrine cells release acetylcholine primarily by vesicle exocytosis and release GABA primarily by means of a carrier [15].
• Among subtypes of amacrine cells grouped by neurotransmitter phenotypes, the glycinergic and gamma-aminobutyric acid (GABA)ergic amacrine cells constitute two major subpopulations [16].
• Clonal territory analysis in X-inactivation transgenic mice confirms the lateral displacement of ChAT amacrine cells away from their clonal columns of origin, and mathematical models show how short-range cellular interactions can guide the assemblage of these mosaics via a simple biological rule [17].
• Intraocular administration of BDNF rescued dopaminergic amacrine cells from neurodegeneration and counteracted the downregulation of TH expression, demonstrating its therapeutic potential [18].
• Flt-1 and KDR gene expression and immunolocalization occurred in VEGF-expressing ganglion, Müller and amacrine cells in normal eyes [19].

Anatomical context of Amacrine Cells

• Iontophoretic injection of Lucifer yellow into the labeled cells under microscopic control revealed that the serotonin-accumulating neurons in rabbit retina constitute two morphological types of amacrine cells, termed S1 and S2, whose distal dendrites are stratified at the inner margin of the inner plexiform layer [20].
• Taken together, our results suggest that connexins are expressed in bipolar cells in a neuronal subtype-specific manner and that cx36/cx36 gap junctions form the heterologous electrical synapses between AII amacrine cells and BPGus-GFP cells [21].
• Fibroblast growth factor receptor blockade results in almost a 50% loss of photoreceptors and amacrine cells, and a concurrent 3.5-fold increase in Müller glia, suggesting a shift towards a Müller cell fate in the absence of a fibroblast growth factor receptor signal [22].
• To ascertain the effects of glycine-accumulating bipolar and amacrine cells on the response properties of retinal ganglion cells, in vivo iontophoretic studies were performed in the cat eye [23].
• Our results indicate the existence of three classes of presumed amacrine cell synaptic terminals: synapsin I+/synapsin II-, synapsin I-/synapsin II+, and synapsin I+/synapsin II+ [24].

Associations of Amacrine Cells with chemical compounds

• Like conventional amacrine cells they are swiftly and selectively destroyed by low concentrations of kainic acid, a neurotoxin [25].
• The existence of separate gamma-aminobutyric acid- and glycine-releasing amacrine cells is implied by these results [26].
• The unique structure of this type of amacrine cell suggests a function for dopamine in long-range lateral interactions in the inner plexiform layer [27].
• The neurotransmitter acetylcholine (ACh) can be detected in the medium of many of these retinal cultures, after release presumably from the choline acetyltransferase-positive amacrine cells [28].
• This was achieved by the discovery that the combined uptake of dopamine and the indoleaminergic transmitter analog 5,7-dihydroxytryptamine leads to an intense, catecholamine-like fluorescence in the cell bodies and processes of presumed dopaminergic amacrine cells in the living retina [27].

Gene context of Amacrine Cells

• These results indicate that Foxn4 is both necessary and sufficient for commitment to the amacrine cell fate and is nonredundantly required for the genesis of horizontal cells [29].
• Moreover, we have located cx36 puncta at the axonal terminals of BPGus-GFP cells, and we have found that these BPGus-GFP-associated cx36 puncta always colocalized with AII amacrine cell processes [21].
• RPGRIP is also expressed in other neurons such as amacrine cells [30].
• Taken together, our data suggest that Barhl2 may function to specify the identity of glycinergic amacrine cells from competent progenitors during retinogenesis [16].
• A third element in Pax6 intron 4, when combined with either the P0 or P1 promoter, accurately directs expression in amacrine cells, ciliary body and iris [31].

Analytical, diagnostic and therapeutic context of Amacrine Cells

• Since, in both cat and rabbit, endogenous 5-HT could not be found by immunocytochemistry, one must consider the possibility that some GABAergic amacrine cells take up indoleamines [32].
• A small group of amacrine cells, possibly those that synthesize acetylcholine, became pyknotic; but the other retinal neurons remained normal to both light and electron microscopy even upon exposure to intraocular concentrations as high as 1 mM [33].
• A high-affinity uptake mechanism for [3H]-gamma-aminobutyric acid (GABA) has been localized to type H1 cone horizontal cells and type Ab pyriform amacrine cells in the retina of the goldfish by light and electron microscopy autoradiography [34].
• Immunofluorescence labeling was performed to study the expression of high voltage-activated Ca(2+) channel subunits on rat retinal cholinergic and dopaminergic amacrine cells, which were double labeled with antibodies against choline acetyltransferase and tyrosine hydroxylase, respectively [35].
• The ultrastructural features and synaptic interactions of tyrosine hydroxylase-like-immuno-reactive amacrine cells in the larval tiger salamander retina were examined using routine immunoelectron microscopy [36].

References