Age-dependent kainate sensitivity in heterozygous rolling Nagoya Cav2.1 channel mutant mice

作者:Kim Tae Yeon; Yoshimoto Takuro; Aoyama Yo; Niimi Kimie; Takahashi Eiki*; Itakura Chitoshi
来源:Pharmacology Biochemistry and Behavior, 2014, 124: 250-259.
DOI:10.1016/j.pbb.2014.06.022

摘要

Cav2.1 alpha(1) is involved in glutamate release. The kainate-induced intensive firing of neurons via glutamate receptors causes seizure and neuronal damage, especially in the hippocampus. Cav2.1 alpha(1) mutation in homozygous rolling Nagoya (rol/rol) mice caused reduced Ca2+ permeability compared to wild-type mice. The rol/rol mice exhibited ataxia approximately after 2 weeks of age. Although we have reported that heterozygous rolling Nagoya (rol/+) mice show age-dependent behavioral changes, sensitivity to kainate has not been examined. To examine the relationship between Cav2.1 function and neurological disease, we investigated how Cav2.1 is related to kainate-induced seizure and neuronal damage using 2- and 18-month-old rol/+ mice. The seizure scores of 18-month-old rol/+ mice that received 20 mg/kg kainate intraperitoneally were significantly lower than those of wild-type mice. As a consequence of seizure, kainate induced delayed neuronal damage along with astrocytic growth in the hippocampus in wild-type mice, with a moderate effect observed in rol/+ mice. In the hippocampus of 18-month-old rol/+ mice, the levels of mutant-type Cav2.1 alpha(1) were increased compared to +/+ mice. The phosphorylation of p38, a mitogen-activated protein kinase (MAPK) activated by kainate, was not increased after kainate injection compared to +/+ mice. No difference was observed between 2-month-old rol/+ and wild-type mice intraperitoneally injected with 20 mg/kg kainate in these analyses. These findings suggest that rol/+ mice experience age-related changes in sensitivity to kainate due to changes in the p38 MAPK signaling pathway via a mutant Cav2.1 channel. Hence, rol/+ mice may represent a novel model to delineate the association between Cav2.1 function, synaptic transmission, and the postsynaptic signaling cascade.

  • 出版日期2014-9
  • 单位RIKEN