1. Abnormal Myelin in Mice Lacking ClC-2
Judith Blanz, Michaela Schweizer, Muriel Auberson, Hannes Maier, Adrian Muenscher, Christian A. Hbner, and Thomas J. Jentsch
The hunt for genes that increase susceptibility to disease is fraught with twists and turns. Heterozygous mutations in the plasma membrane chloride channel ClC-2 have been linked to human epilepsy in three families. However, Blanz et al. found a quite different phenotype in mice that were either heterozygous or deficient in Clcn2. This widely expressed chloride channel is activated by cell swelling, lowered pH, and voltage. Mice lacking Clcn2 showed spongiform vacuolation of the central white matter, basically a picture of fluid-filled holes between myelin sheets. This pattern was apparent at 2 months of age and increased further with age. The peripheral nerves were unaffected. Blindness was the most obvious consequence of ClC-2 loss, presumably from the retinal damage described previously in these mice. However, neurons appeared normal, and there was no effect on seizure threshold. The pattern of white matter injury suggests that ClC-2 is involved in extracellular ion homeostasis in oligodendrocytes.
2. EGFR Inhibitors and Spinal Cord Injury
atthias Erschbamer, Karin Pernold, and Lars Olson
After spinal cord injury (SCI), physical and molecular barriers inhibit axon regeneration. These impediments arise in part from a glial scar consisting of reactive astrocytes as well as astrocytic release of growth inhibitors such as chondroitin sulfate proteoglycans. These astrocytic events can be triggered by activation of the epidermal growth factor receptor (EGFR); thus, Erschbamer et al. tested the potential benefit of permanently blocking the receptor after SCI. Rats received a contusion injury, and for 14 d received intrathecal injection of either vehicle or the irreversible EGFR inhibitor PD168393 (4-[3(bromophenyl)-amino]-6-acrylami
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Society for Neuroscience