Comparison of adenosine uptake and endogenous adenosine-containing cells in mammalian retina

Abstract

Autoradiographic techniques were used to label [ 3 H]-adenosine and [ 3 H]-cyclohexyladenosine accumulating cells in rabbit, mouse, and ground squirrel retinas. Immunohistochemical methods revealed the distribution of cells that stained for endogenous adenosine. Comparisons of these two markers revealed for all three species that the distribution of specific subpopulations of retinal cells that store or accumulate the purine nucleoside, adenosine, is similar. For all three species, cells localized in the ganglion cell layer accumulated adenosine and exhibited adenosine-like immunoreactivity (ALIR). A smaller proportion of cells localized in the inner nuclear layer were labeled for ALIR, while a larger proportion of cells in this layer accumulated adenosine. Subtle differences between species are presented. However, the general similarities of the distribution of these two putative purinergic markers supports the evidence that a discrete adenosinergic neurotransmitter/modulatory system is present in the retina.

Adenosine inhibits calcium channel currents via A1 receptors on salamander retinal ganglion cells in a mini‐slice preparation

“…Retinal ganglion cells may also be the source of adenosine that acts on these receptors (Braas et al . 1987; Blazynski et al . 1989), suggesting that adenosine may be a co‐transmitter released from ganglion cell terminals and, by modulating calcium currents on the terminals of ganglion cell, control the release of glutamate.…”

“…A 1 adenosine receptors have been identified within the mammalian retina and were localized to the optic nerve fiber layer, the ganglion cell layer and the inner plexiform layer (Braas et al . 1987; Blazynski et al . 1989).…”

Displaced cholinergic, GABAergic amacrine cells in the rabbit retina also contain adenosine

“…Perez and Bruun (1987) have also reported that certain of the cell bodies in the GCL that accumulate [ 3 H]-adenosine are also labeled for GABA-like immunoreactivity. We had previously demonstrated that a large number of cell bodies localized to the GCL were labeled by an antisera generated against a derivative of adenosine (Blazynski et al, 1989;Braas et al, 1987). We have now identified these labeled cells as both true ganglion cells and displaced amacrine cells, and demonstrate that, of the latter group of cells, many are also labeled for GAD-like immunoreactivity and accumulate the dye DAPI, a marker for cholinergic cells in the rabbit retina.…”

“…Since ganglion cells comprise about two-thirds of the cells in the GCL (Vaney, 1980), then approximately half of the remaining displaced amacrine cells may have been labeled for these two markers. Thus, within this subset of displaced amacrine cells localized within the GCL, uptake systems for GABA (Mosinger & Yazulla, 1985), adenosine (Ehinger & Perez, 1984;Blazynski et al, 1989), and choline (Masland et al, 1984a) have been demonstrated. In addition, as seen in Fig.…”

“…Evidence for a purinergic system in vertebrate retina is accumulating. Reprint Both classes of adenosine receptors have been biochemically demonstrated (Paes de Carvalho & de Mello, 1985;Blazynski et al, 1986;de Mello et al, 1982;Blazynski, 1987), and neurons that contain endogenous stores of adenosine (Braas et al, 1987;Blazynski et al, 1989) and which accumulate adenosine (Ehinger & Perez, 1984;Blazynski et al, 1989) have been localized in mammalian retina. The distribution of A, receptors has also been demonstrated by specific binding of A!…”