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

Purpose: Little is known about the expression of GABA transporters (GATs) i n the developing retina. We have therefore examined the expression of GABA transporters (GAT1 and GAT3) in the developing rabbit retina. Methods: The distribution of GATs was examined with immunohistochemical met hods. Results: GAT3 immunoreactivity appeared at PN0, whereas GAT1 immunoreactivi ty appeared first at PN3, both in the inner plexiform layer. From PN5 and o nwards, both GAT1 and GAT3 immunoreactivity gradually appeared in numerous amacrine cell somas, At PN10, the immunostaining patterns and the distribut ion of both GAT1 and GAT3 were similar to that found in the adult rabbit re tina. Full staining intensity was reached at PN20, Conclusion: GABA neurotransmission starts to develop already the first one to three days after birth, reaches the mature neuron pattern at about PN9 t o PN10 but is not fully developed until about PN20, Neither GAT1 nor GAT3 a ppears to be involved in trophic actions by GABA in the prenatal retina.