Expression of GABA transporter subtypes (GAT1, GAT3) in the adult rabbit retina

Purpose: GABA transporters (GATs) are of importance for GABA signal systems , They have previously not been examined in rabbit retina, nor has their co rrelation with neurotransmitter GABA and GABA receptors been examined in th e retina of any species, Methods: The distribution of GATs, GABA and GABA receptors was examined,vit h immunohistochemical methods. Results: Both GAT1 and GAT3 immunoreactivities were found in the inner plex iform layer and in amacrine cells, GAT3 was also present in Muller cells. G AT1 appeared in amacrine cells that also had a high GABA concentration, but not in cells with moderate to low GABA concentration. GAT1 was also presen t in amacrine cells that did not show GABA immunoreactivity, possibly indic ating a postsynaptic GABA uptake system, Conclusion: GAT3 is probably involved in both neuronal and glial GABA uptak e whereas GAT1 is involved in predominantly neuronal uptake, and possibly a lso into non-GABA-ergic amacrine cells, Further, there may be at least two populations of GABA containing neurons.