低体温下の心臓活動　冬眠ほ乳動物の心筋Ｃａイオン調節機構に学ぶ

• 近藤 宣昭

  三菱化学生命科学研究所,(財)神奈川科学技術アカデミー・近藤冬眠制御プロジェクト

書誌事項

タイトル別名

• Heart Function under Hypothermia. Study on Mechanism of Ca Ion Regulation in Hearts of Mammalian Hibernators.
• Study on Mechanism of Ca Ion Regulation in Hearts of Mammalian Hibernators
• 冬眠哺乳動物の心筋Caイオン調節機構に学ぶ

抄録

Most mammals are not capable of surviving at low body temperature for extended periods. Although some degree of hypothermia provides an advantage in medical treatment, such as organ plantation and open heart surgery, through depression of the energy consumption and prevention of accumulation of harmful metabolites, the lowering of body temperature causes serious cold-damage to cells, probably by overloading Ca²⁺, resulting from a perturbation of membrane ion regulation. Mammalian hibernators undergo extreme hypothermia (near 0°C) during hibernation without any damage to their bodies, indicating the existence of an effective strategy for the protection of cells and tissues against cold. Recent studies on excitation-contraction coupling of cardiac muscles of hibernators found dramatic changes in Ca²⁺ regulatory systems, Ca channels and sarcoplasmic reticulum (SR), during hibernation. The contraction usually depends on Ca²⁺ influx through Ca channels, whereas during hibernation, Ca²⁺ for contraction is derived mainly from intracellular Ca stores, SR. Further electrophysiological and biochemical studies in hibernating animals revealed that these are attributed to both the marked enhancement of the Ca²⁺ uptake ability of SR and much less activation of Ca channels. These changes greatly contribute to the reduction of cytoplasmic Ca²⁺ after contraction. Thus, during hibernation, hearts are kept functioning normally at low body temperature through avoiding Ca²⁺ overload. The present mechanism of adaptation to cold provides a useful model for studying a strategy for overcoming cold injury.

収録刊行物

• 動物の循環器

  動物の循環器 28 (2), 71-76, 1995

  日本獣医循環器学会

キーワード

• Ca<SUP>2+</SUP> regulation
• cold tolerance
• heart
• mammalian hibernation
• sarcoplasmic reticulum

詳細情報

• CRID: 1390001206459675776
• NII論文ID: 10008286822
• NII書誌ID: AN10192925
• DOI: 10.11276/jsvc1984.28.71
• ISSN: 18835260
• ISSN: 09106537
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可