Hydroxyl Radical-Mediated Reduction of Ca2+-ATPase Activity of Masseter Muscle Sarcoplasmic Reticulum.

• Lee Chang-il

  <I>Department of Pharmacology, Kanagawa Dental College</I>

• Okabe Eiichiro

  <I>Department of Pharmacology, Kanagawa Dental College</I>

抄録

To understand the effect of oxygen free radicals on Ca²⁺-ATPase, we used sarcoplasmic reticulum (SR) microsomes of canine masseter muscle as a model system in which to explore the effects of oxidation on a biological membrane, and we investigated the effect of hydroxyl radicals (·OH) generated from Fenton''s reagent (H₂0₂/FeSO₄). H₂0₂(10 mM) alone had no effect on Ca²⁺ -ATPase activity; in the presence of FeSO₄ (0.2 mM), H₂0₂ inhibited the enzyme activity. Oxygen free radical species generated from H₂0₂/FeSO₄ under the conditions employed in the Ca²⁺ -ATPase assay were verified by highly sensitive electron spin resonance spectroscopy and the spin-trap 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) in the absence of SR vesicles; the 1:2:2:1 quartet (A_N= A_H=1.49 mT), characteristic of the DMPO-OH spin adduct, was observed. The Ca²⁺ -ATPase activity was inversely correlated with the calculated signal intensity of DMPO-OH, which is indicative of the amount of ·OH radical generated. The effect of Fenton''s reagent was effectively inhibited by catalase, dimethylsulfoxide, and dimethylthiourea; the effect was also inhibited by sulfhydryl (SH) group reducing agents, cysteine and dithiothreitol. The SH group modifying agents, p-chloromercuric benzoate and 5, 5'' -dithiobis(2-nitrobenzoic acid) depressed Ca²⁺-ATPase activity; the effects of the SH group modifying agents used were potentiated in the presence of Fenton''s reagent. It is suggested that ·OH radical-induced oxidant injury may be caused primarily by modification of the key SHgroup(s) on the ATPase molecule of masseter muscle SR vesicles.

収録刊行物

• Jpn.J.Pharmacol.

  Jpn.J.Pharmacol. 67 (1), 21-28, 1995

  公益社団法人 日本薬理学会

キーワード

• Hydroxyl radical
• Ca<SUP>2+</SUP>-ATPase
• Sarcoplasmic reticulum
• Masseter muscle
• Sulfhydryl group

詳細情報

• CRID: 1390001204286706816
• NII論文ID: 10005709764
• NII書誌ID: AA00691188
• DOI: 10.1254/jjp.67.21
• COI: 1:CAS:528:DyaK2MXjtlKhsLo%3D
• ISSN: 13473506
• ISSN: 00215198
• ISSN: http://id.crossref.org/issn/00215198
• PubMed: 7745841
• Web Site: https://api.elsevier.com/content/article/PII:S0021519819356306?httpAccept=text/xml
• Web Site: https://api.elsevier.com/content/article/PII:S0021519819356306?httpAccept=text/plain
• Web Site: https://search.jamas.or.jp/link/ui/1996101520
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • PubMed
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可