ISSN:
1432-1106
Keywords:
Key words Weaver mice
;
Heterozygote
;
Cerebellar granule cells
;
Calcium
;
GIRK2
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The pleiotropic weaver disease is caused by the mutation of a single amino acid in the G-protein-linked inwardly rectifying K+ channel, GIRK2. In homozygous (wv/wv) animals, the disease is characterized by loss of cerebellar and dopaminergic mesencephalic neurons as well as testicular cells, which produce ataxia, fine tremors, and sterility, respectively. Heterozygous (wv/+) animals show no obvious motor impairments, although some loss of both cerebellar and dopaminergic neurons is observed and wv/+ males become sterile at 3.5 months of age. Abnormal influxes of Na+ and Ca2+ have been linked to cerebellar cell death in wv/wv animals, but it’s not clear whether similar changes are observed in wv/+ animals. To discover whether changes in K+-channel function or intracellular Ca2+ concentrations ([Ca2+]i) play a role in the augmented cell loss observed in wv/+ animals when compared with +/+ animals, we studied cultured cerebellar granule cells prepared from either wv/+ or +/+ animals. Resting [Ca2+]i was elevated in wv/+ relative to +/+ animals. Further, depolarizations of cells with elevated K+ solutions elicited much smaller changes in [Ca2+]i in wv/+ animals than in +/+ animals, presumably due to altered GIRK2 channel function. Both wv/+ and +/+ cells showed similar changes in [Ca2+]i when cells were depolarized by glutamate (1 mM), suggesting that both glutamate receptors and Ca2+ channels were unchanged in wv/+ animals. In summary, our results suggest that wv/+ cerebellar granule cells exhibit elevated resting [Ca2+]i levels and altered K+-channel function, which may contribute to the developmental abnormalities and increased cell death observed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002210050572
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