Colocalization of GABA-immunoreactivity in neuropeptide- and monoamine-containing amacrine cells in the retina of Bufo marinus.

Abstract

Summary. Immunocytochemical study was performed in the Bufo marinus retina to reveal the localization of y-aminobutyric acid (GABA)-immunoreactivity in neuropeptide Y (NPY)-, substance P (SP)-, serotonin (5HT)-and tyrosin hydroxylase (TH)-immunoreactive amacrine cells. GABA-immunoreactivity was present in all NPY-, in some of the SP-and 5HT-containing amacrine cells, but not in TH-immunoreactive amacrine cells. Among the 5HT-immunoreactive amacrine cells, a population of 5HT-synthesizing and most of the 5HT-accumulating cells were GABA-immunoreactive. These results indicate that neuropeptide-and GABA-immunoreactivity are colocalized in amacrine cells of the anuran retina. We propose a possible co-transmission for two classical neurotransmitters (GABA and 5HT) in some of the 5HT-containing amacrine cells.Previous studies have indicated that the y-aminobutyric acid (GABA)-ergic amacrine cell population is morphologically (POURCHO and GOEBEL, 1983;YANG et al., 1991) and immunohistochemically (VERSAUX-BOTTERI et al

Neuropeptide Y-Immunoreactive Neurons in the Retina of Two Australian Lizards.

“…The colocalization of GABA and NPY in these cells is almost 100% (MAIN et al, 1993). GABA-activated current responses are potentiated by neuropeptide Y (VERUKI and YEH, 1992).…”

Distribution and regulation of substance P‐related peptide in the frog visual system

“…The remaining SPL-ir cells are located in the innermost cell row of the inner nuclear layer or in the retinal ganglion cell layer and contain GABA and/or high-affinity GABA uptake sites (Watt et al, 1994). GABA immunoreactivity also colocalizes with some SPL-ir amacrine cells in the retina of Bufo marinus (Main et al, 1993). This colocalization is more pronounced in the cat retina where all SPL-ir cells also are GABA immunoreactive (Pourcho and Goebel, 1988;Vaney et al, 1989).…”

A double-label analysis demonstrating the partial coexistence of tyrosine hydroxylase and GABA in retinal neurons of Ichthyophis kohtaoensis (Amphibia; Gymnophiona)

“…Provided that caecilian retinal neurotransmitters still perform certain tasks, a self-regulation of synaptic activity by coexisting neurochemical substances (Lam et al 1986; Main et al 1993) probably serves to discriminate alterations in illumination intensity. Independent of complex pattern recognition, the dopaminergic system of the caecilian retina might perform similar light-and dark-adaptive functions as in other vertebrates (Besharse and Iuvone 1992), probably supported by the GABAergic system, providing a synaptic fine-tuning (Davanger et al 1991).…”