TY - JOUR
T1 - Activation of μ-calpain in developing cortical neurons following methylmercury treatment
AU - Zhang, Jian
AU - Miyamoto, Ken Ichiro
AU - Hashioka, Sadayuki
AU - Hao, Hai Peng
AU - Murao, Koji
AU - Saido, Takaomi C.
AU - Nakanishi, Hiroshi
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2003/4/14
Y1 - 2003/4/14
N2 - In order to examine the possible involvement of μ-calpain in methylmercury (MeHg)-induced neurotoxicity in developing cortical neurons, we performed biochemical and immunohistochemical studies utilizing two antibodies which specifically recognize the 150-kDa μ-calpain-specific α-spectrin breakdown product (SBDP) and the active form of μ-calpain in rats on postnatal day 16. Soluble fractions of the cerebral cortex from control rats exhibited slight immunoreactivity for SBDP. Although the amount of SBDP in the cerebral cortex was only slightly increased the day after the final treatment of MeHg (10 mg/kg) for 3 or 7 consecutive days, there was a prominent accumulation of SBDP 3 days after the final treatment of MeHg for 7 consecutive days. On the other hand, the 76-kDa isoform of μ-calpain gradually increased after chronic treatment of MeHg, but markedly decreased 3 days after the final treatment of MeHg for 7 consecutive days. At this stage, many cortical neurons were densely stained with anti-SBDP antibody. The delayed increase in SBDP corresponded well with the delayed nature of the MeHg-induced neurotoxicity. When MK-801 (0.1 mg/kg), a non-competitive antagonist of N-methyl-D-aspartate (NMDA), was administered intraperitoneally with MeHg for 7 consecutive days, both neuronal damage and accumulation of SBDP were markedly depressed in the cerebral cortex 3 days after the final treatment. Our results indicate that μ-calpain activation and μ-calpain-mediated proteolysis of α-spectrin preceded neuronal damage in the developing cerebral cortex induced by chronic treatment of MeHg.
AB - In order to examine the possible involvement of μ-calpain in methylmercury (MeHg)-induced neurotoxicity in developing cortical neurons, we performed biochemical and immunohistochemical studies utilizing two antibodies which specifically recognize the 150-kDa μ-calpain-specific α-spectrin breakdown product (SBDP) and the active form of μ-calpain in rats on postnatal day 16. Soluble fractions of the cerebral cortex from control rats exhibited slight immunoreactivity for SBDP. Although the amount of SBDP in the cerebral cortex was only slightly increased the day after the final treatment of MeHg (10 mg/kg) for 3 or 7 consecutive days, there was a prominent accumulation of SBDP 3 days after the final treatment of MeHg for 7 consecutive days. On the other hand, the 76-kDa isoform of μ-calpain gradually increased after chronic treatment of MeHg, but markedly decreased 3 days after the final treatment of MeHg for 7 consecutive days. At this stage, many cortical neurons were densely stained with anti-SBDP antibody. The delayed increase in SBDP corresponded well with the delayed nature of the MeHg-induced neurotoxicity. When MK-801 (0.1 mg/kg), a non-competitive antagonist of N-methyl-D-aspartate (NMDA), was administered intraperitoneally with MeHg for 7 consecutive days, both neuronal damage and accumulation of SBDP were markedly depressed in the cerebral cortex 3 days after the final treatment. Our results indicate that μ-calpain activation and μ-calpain-mediated proteolysis of α-spectrin preceded neuronal damage in the developing cerebral cortex induced by chronic treatment of MeHg.
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U2 - 10.1016/S0165-3806(03)00057-9
DO - 10.1016/S0165-3806(03)00057-9
M3 - Article
C2 - 12694949
AN - SCOPUS:0037954514
VL - 142
SP - 105
EP - 110
JO - Developmental Brain Research
JF - Developmental Brain Research
SN - 0165-3806
IS - 1
ER -