PT - JOURNAL ARTICLE AU - Jeff Seinfeld AU - Neema Baudry AU - Xiaobo Xu AU - Xiaoning Bi AU - Michel Baudry TI - Differential Activation of Calpain-1 and Calpain-2 following Kainate-Induced Seizure Activity in Rats and Mice AID - 10.1523/ENEURO.0088-15.2016 DP - 2016 Jul 01 TA - eneuro PG - ENEURO.0088-15.2016 VI - 3 IP - 4 4099 - http://www.eneuro.org/content/3/4/ENEURO.0088-15.2016.short 4100 - http://www.eneuro.org/content/3/4/ENEURO.0088-15.2016.full SO - eneuro2016 Jul 01; 3 AB - Systemic injection of kainate produces repetitive seizure activity in both rats and mice. It also results in short-term synaptic modifications as well as delayed neurodegeneration. The signaling cascades involved in both short-term and delayed responses are not clearly defined. The calcium-dependent protease calpain is activated in various brain structures following systemic kainate injection, although the precise involvement of the two major brain calpain isoforms, calpain-1 and calpain-2, remains to be defined. It has recently been reported that calpain-1 and calpain-2 play opposite roles in NMDA receptor-mediated neuroprotection or neurodegeneration, with calpain-1 being neuroprotective and calpain-2 being neurodegenerative. In the present study, we determined the activation pattern of calpain-1 and calpain-2 by analyzing changes in levels of different calpain substrates, including spectrin, drebrin, and PTEN (phosphatase and tensin homolog; a specific calpain-2 substrate) in both rats, and wild-type and calpain-1 knock-out mice. The results indicate that, while calpain-2 is rapidly activated in pyramidal cells throughout CA1 and CA3, rapid calpain-1 activation is restricted to parvalbumin-positive and to a lesser extent CCK-positive, but not somatostatin-positive, interneurons. In addition, calpain-1 knock-out mice exhibit increased long-term neurodegeneration in CA1, reinforcing the notion that calpain-1 activation is neuroprotective.