Comparison of the localization of acetylcholinesterase and non‐specific cholinesterase activities in mammalian and avian retians

Abstract

The localization of acetylcholinesterase and non-specific cholinesterase was studied in the cone retinas of the pigeon and ground squirrel, and in the predominantly rod retinas of the rabbit, rat and cat. The enzymes were localized histochemically using the copper or gold thiocholine method. In the cone retinas, acetylcholinesterase was found in discrete bands in the inner plexiform layer. Cells corresponding in position and morphological detail to amacrine cells were stained for acetylcholinesterase. Cells of the ganglion cell layer that resembled displaced amacrine cells were also stained for acetylcholinesterase, as well as other cells that appeared to be ganglion cells. No stained processes could be followed from these latter cells, however. The horizontal cells were stained for non-specific cholinesterase; these cells were localized to specific areas of the retina, which differed in the two species. In the predominantly rod retinas, there was no staining for non-specific cholinesterase, but there was diffuse staining for acetylcholinesterase throughout the inner plexiform layer. In the rabbit, this staining pattern was not changed by chronic section of the optic nerve. No stained amacrine cells could be seen distinctly in any of the three species with predominantly rod retinas. After an intravenous dose of diisopropyl phosphorofluoridate sufficient to inactivate all the retinal acetylcholinesterase, however, synthesis of new enzyme could be followed in the amacrine cells and their processes. In all five species examined, therefore, the amacrine cells appeared to be the major or sole source of acetylcholinesterase for the inner plexiform layer of the retina. The possible function of this enzyme with regard to synaptic transmission in the retina is discussed.

RELEASE OF [3H]-ACETYLCHOLINE FROM THE ISOLATED RETINA OF THE RAT BY POTASSIUM DEPOLARIZATION: DEPENDENCE ON HIGH AFFINITY CHOLINE UPTAKE

“…(Baughman & Bader, 1977). This is consistent with other evidence which suggests that cholinergic synapses in the retina occur predominantly in the inner plexiform layer and that a sub-population of amacrine cells is cholinergic (Nichols & Koelle, 1968;Neal, 1976a;Ross & McDougal, 1976;Masland & Ames, 1976;Vogel, Maloney, Ling & Daniels, 1977;Massey & Neal, 1978). If the sites of [3H]-choline uptake in the rat retina are similar to those in the chicken (but see Neal (1976b) for the importance of species differences in the retina) then the [3H]-ACh released by potassium depolarization presumably originated from amacrine and/or bipolar cells.…”

Histochemical Localization of Dopamine and Acetylcholinesterase Activity in the Carp Retina

“…The cellular localization of AchE activity in the carp retina was consistent with earlier findings (4,9,29,31). AchE activity was found in a certain group of amacrine cells and in some ganglion cells, diffusely in the IPL and weakly in the external horizontal cell layer.…”

“…The cellular localization of AchE and the Ach metabolism in the retina have been also extensively investigated (4,9,29,31). It has been commonly described that AchE activity is predominantly positive in amacrine and ganglion cells and at the IPL.…”

Localization of acetylcholine receptors during synaptogenesis in retina.

“…The retina contains acetylcholine and enzymes that catalyze the synthesis and the hydrolysis of this compound (13-17). In addition, electrophysiologic studies show that some neurons in retina respond to acetylcholine and that both nicotinic and muscarinic AcCh receptors are present in the retina of certain organisms (18)(19)(20)(21)(22).In this report, the concentration of nicotinic AcCh receptors and their location in chick embryo retina are described as a function of the developmental age of the retina. H-21) with 20 mM Hepes (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid), pH 7.4, instead of NaHCO3, and 2 mg of serum albumin per ml of medium].…”