PMID:10670432

Citation	Ayata, C, Shimizu-Sasamata, M, Lo, EH, Noebels, JL and Moskowitz, MA (2000) Impaired neurotransmitter release and elevated threshold for cortical spreading depression in mice with mutations in the alpha1A subunit of P/Q type calcium channels. Neuroscience 95:639-45
Abstract	The P/Q type voltage-gated Ca2+ channels are involved in membrane excitability and Ca2+-dependent neurotransmitter release within the CNS. Mutations in the CacnalA gene encoding the alpha1A subunit of the P/Q type Ca2+ channel have recently been reported in tottering mice and a more severely affected allele, leaner. Here we show using in vivo cortical microdialysis that evoked increases of extracellular glutamate levels are markedly attenuated in both mutants upon KCl-induced depolarization compared with wild-type mice. Tottering and leaner mice also show a 10-fold resistance to cortical spreading depression induced by cortical electrical stimulation or KCl application to the pial surface. A slower transcortical propagation speed and failure to sustain regenerative spread of the depolarizing wave were more pronounced in leaner neocortex. Both signaling defects appeared unrelated to the developmental history of repeated cortical spike-wave discharges, since neither were observed in the stargazer mouse, a Ca2+ channel gamma2 subunit mutant with a similar seizure phenotype. These data demonstrate two cortical excitability defects revealed by prolonged depolarization in cerebral networks expressing mutant P/Q type Ca2+ channels, and are the first to identify a gene linked to a spreading depression phenotype.
Links	PubMed
Keywords	Animals; Calcium Channels, P-Type/genetics; Cortical Spreading Depression/physiology; Differential Threshold/physiology; Electrophysiology; Female; Male; Mice; Mice, Inbred C57BL; Mice, Neurologic Mutants; Mutation/physiology; Neurotransmitter Agents/metabolism; Potassium/pharmacology; Protein Isoforms/genetics; Reference Values
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Gene product	Qualifier	GO ID	GO term name	Evidence Code	with/from	Aspect	Notes	Status
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