Effects of Strontium as Substitute for Extracellular Calcium on Contraction and Relaxation of Vascular Smooth Muscle

  • Eiichi Uchida


Contraction of a muscle is activated by a rise in intracellular free-Ca2+ concentration (1). It was shown that there are different trigger mechanisms that activate the contractile apparatus of vascular smooth muscle by causing an increase in the intracellular Ca2+ concentration (2). The source of Ca2+ may be extracellular, intracellular, or both, depending on the type of trigger mechanisms (2,3). At present, the source of the activator Ca2+ of individual trigger mechanisms remains the subject of study. In contraction of various types of muscles, it is known that Sr2+ is effective as a substitute for external Ca2+ (4–7). The purpose of this report is to determine whether Sr2+ can substitute for external Ca2+ in inducing contraction and relaxation and to compare the effectiveness between Ca2+ and Sr2+ in several types of contraction and relaxation of vascular smooth muscle. The following different types of contraction were selected as representative samples to be studied: (1) spontaneous rhythmic contraction of rat portal vein, (2) spontaneous tonic contraction of rat skeletal muscle artery, (3) potassium-induced contraction of dog external jugular vein and dog mesenteric artery, and (4) norepinephrine-induced contraction of dog external jugular vein and dog mesentric artery.


Vascular Smooth Muscle Contractile Response Phasic Contraction Tonic Contraction Physiological Salt Solution 
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Copyright information

© Plenum Press, New York 1981

Authors and Affiliations

  • Eiichi Uchida
    • 1
  1. 1.The Cardiovascular InstituteTokyoJapan

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