AUTHOR=Tanaka Mika , Yamaguchi Kazuhiko , Tatsukawa Tetsuya , Nishioka Chieko , Nishiyama Hiroshi , Theis Martin , Willecke Klaus , Itohara Shigeyoshi 

TITLE=Lack of connexin43-mediated Bergmann glial gap junctional coupling does not affect cerebellar long-term depression, motor coordination, or eyeblink conditioning

JOURNAL=Frontiers in Behavioral Neuroscience

VOLUME=2

YEAR=2008

URL=https://www.frontiersin.org/journals/behavioral-neuroscience/articles/10.3389/neuro.08.001.2008

DOI=10.3389/neuro.08.001.2008

ISSN=1662-5153

ABSTRACT=<p>Bergmann glial cells are specialized astrocytes in the cerebellum. In the mature cerebellar molecular layer, Bergmann glial processes are closely associated with Purkinje cells, enclosing Purkinje cell dendritic synapses with a glial sheath. There is intensive gap junctional coupling between Bergmann glial processes, but their significance in cerebellar functions is not known. Connexin43 (<abbrev>Cx43</abbrev>), a major component of astrocytic gap junction channels, is abundantly expressed in Bergmann glial cells. To examine the role of <abbrev>Cx43</abbrev>-mediated gap junctions between Bergmann glial cells in cerebellar functions, we generated <italic><abbrev>Cx43</abbrev></italic> conditional knockout mice with the <italic>S100b-Cre</italic> transgenic line (<italic>Cx43<sup>fl/fl</sup></italic>:<italic>S100b-Cre</italic>), which exhibited a significant loss of Cx43 in the Bergmann glial cells and astrocytes in the cerebellum with a postnatal onset. The <italic>Cx43<sup>fl/fl</sup></italic>:<italic>S100b-Cre</italic> mice had normal cerebellar architecture. Although gap junctional coupling between the Bergmann glial cells measured by spreading of microinjected Lucifer yellow was virtually abolished in <italic>Cx43<sup>fl/fl</sup></italic>:<italic>S100b-Cre</italic> mice, electrophysiologic analysis revealed that cerebellar long-term depression could be induced and maintained normally in their cerebellar slices. In addition, at the behavioral level, <italic>Cx43<sup>fl/fl</sup></italic>:<italic>S100b-Cre</italic> mice had normal motor coordination in the rotarod task and normal conditioned eyelid response. Our findings suggest that <abbrev>Cx43</abbrev>-mediated gap junctional coupling between Bergmann glial cells is not necessary for the neuron-glia interactions required for cerebellum-dependent motor coordination and motor learning.</p>