GAT-1 developmental expression in the rat cerebellar cortex: basket and pinceau formation

IN view of the key role exerted by neurotransmitter transporters in the syn aptic transmission, the expression of GABA transporter GAT-1 was analysed d uring cerebellar development, when relevant processes of synapse maturation take place. GAT-1-immunoreactive (IR) structures started to-be detected on PD 8-9, at the low molecular and Purkinje cell layer, coincident with the onset of functional inhibitory synapses on Purkinje neurons. By PD 18, GAT- 1-IR structures completely ensheathed the Purkinje cell somata thus outlini ng the characteristic perisomatic formation, whereas GAT-1 wrapping on the axon initial segment started to be detected only at PD 15, and the mature f orm of the pinceau was fully developed from PD 23 on. These results, when c ompared with the functional maturation of the GABAergic input to Purkinje c ells, indicate that GAT-1 may play a significant role in the differentiatio n of basket interneuron-Purkinje cell circuit. NeuroReport 10:1613-1618 (C) 1999 Lippincott Williams & Wilkins.