caa a22 4500 477096077 CHVBK 20180405111528.0 cr unu---uuuuu 170330e19961001xx s 000 0 eng 10.1007/BF00198540 doi (NATIONALLICENCE)springer-10.1007/BF00198540 Astrocytic processes compensate for the apparent lack of GABA transporters in the axon terminals of cerebellar Purkinje cells [Elektronische Daten] [Charles Ribak, Winnie Tong, Nicholas Brecha] The aim of the present study was to evaluate the expression of two high affinity GABA transporters (GAT-1 and GAT-3) in the rat cerebellum using immunocytochemistry and affinity purified antibodies. GAT-1 immunoreactivity was prominent in punctate structures and axons in all layers of the cerebellar cortex, and was especially prominent around the somata of Purkinje cells. In contrast, the deep cerebellar nuclei showed few if any GAT-1 immunoreactive puncta. Weak GAT-3 immunoreactive processes were present in the cerebellar cortex, whereas GAT-3 immunostaining was prominent around the somata of neurons in the deep cerebellar nuclei. Electron microscopic preparations of the cerebellar cortex demonstrated that GAT-1 immunoreactive axon terminals formed symmetric synapses with somata, axon initial segments and dendrites of Purkinje cells and the dendrites of granule cells. Astrocytic processes in the cerebellar cortex were also immunolabeled for GAT-1. However, Purkinje cell axon terminals that formed symmetric synapses with neurons in the deep cerebellar nuclei lacked GAT-1 immunoreactivity. Instead, weak GAT 1 and strong GAT-3 immunoreactivities were expressed by astrocytic processes that enveloped the Purkinje cell axon terminals. In addition, GAT-3-immunoreactivity appeared in astrocytic processes in the cerebellar cortex. These observations demonstrate that GAT-1 is localized to axon terminals of three of the four neuronal types that were previously established as being GABAergic, i.e. basket, stellate and Golgi cells. GAT-1 and GAT-3 are expressed by astrocytes. The failure to identify a GABA transporter in Purkinje cells is consistent with previous data that indicated that Purkinje cells lacked terminal uptake mechanisms for GABA. The individual glial envelopment of Purkinje cell axon terminals in the deep cerebellar nuclei and the dense immunostaining of GAT-3, and to a lesser extent GAT-1, expressed by astrocytic processes provide a compensatory mechanism for the removal of GABA from the synaptic cleft of synapses formed by Purkinje cell axon terminals. Springer-Verlag, 1996 Deep cerebellar nuclei nationallicence Cerebellar cortex nationallicence Basket cells nationallicence Stellate cells nationallicence Immunocytochemistry nationallicence Ribak Charles Department of Anatomy and Neurobiology, University of California, 92717, Irvine, CA, USA aut Tong Winnie Department of Anatomy and Neurobiology, University of California, 92717, Irvine, CA, USA aut Brecha Nicholas Department of Neurobiology, UCLA School of Medicine, 90024, Los Angeles, CA, USA aut Anatomy and Embryology Springer-Verlag 194/4(1996-10-01), 379-390 0340-2061 194:4<379 1996 194 429 https://doi.org/10.1007/BF00198540 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00198540 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ribak Charles Department of Anatomy and Neurobiology, University of California, 92717, Irvine, CA, USA aut NATIONALLICENCE 700 1- Tong Winnie Department of Anatomy and Neurobiology, University of California, 92717, Irvine, CA, USA aut NATIONALLICENCE 700 1- Brecha Nicholas Department of Neurobiology, UCLA School of Medicine, 90024, Los Angeles, CA, USA aut NATIONALLICENCE 773 0- Anatomy and Embryology Springer-Verlag 194/4(1996-10-01), 379-390 0340-2061 194:4<379 1996 194 429 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer