NOS-like immunoreactive neurons express GABA-like immunoreactivity in rabbit and rat retinae

In rabbit and rat retinae, wholemounted preparations and 40 microm thick vibratome sections were processed for nitric oxide synthase (NOS) immunoreactivity and consecutive semithin sections were immunostained with anti-NOS and anti-GABA antisera, respectively. Two types of NOS-labelled amacrine cells were identified: type 1 cells with larger somata were intensely stained, and type 2 cells with smaller somata were weakly stained. A few displaced amacrine cells also showed NOS-like immunoreactivity. All these NOS-like immunoreactive neurons also expressed GABA-like immunoreactivity. Thus, nitric-oxide-containing neurons might constitute a subpopulation of GABAergic neurons in rabbit and rat retinae.