Dynamics of GABAρ2 receptors in retinal bipolar neurons and cerebellar astrocytes

Gamma-aminobutyric acid (GABA)ρ receptors are selectively targeted to the axon terminals of the retinal bipolar neurons. The traffic of a green fluorescent protein-tagged GABAρ2 was examined in retinal bipolar neurons and cerebellar astrocytes. In bipolar neurons, time-lapse laser confocal microscopy revealed that the fluorescence emitted by GABAρ2-green fluorescent protein accumulates first, in clusters, in the soma and is then distributed along the axon in at least two populations: one that remains relatively immobile and a second population of smaller clusters that moved constantly to and from the axon end. In astrocytes, the fluorescent clusters were relatively immobile and located mainly in the soma.