A voltage-dependent noradrenaline-sensitive intracellular calcium store in smooth muscle cells of the guinea-pig aorta

Zhang, Y; Vohra, M. M.; Wong, AYK

doi:10.1139/y97-142

Cited by 1 publication

(1 citation statement)

References 27 publications

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“… 17,18 In vascular smooth muscle, it has been reported that a voltage‐dependent noradrenaline‐sensitive Ca 2+ store may be partially responsible for the regulation of [Ca 2+ ] i . 19 Furthermore, depolarization‐induced Ca 2+ release, which is not inhibited by inhibitors of CICR (Mg 2+ and procaine), has also been found in skinned skeletal and smooth muscle. 20 However, in guinea‐pig tracheal muscle there is little evidence as to voltage‐controlled Ca 2+ release that may be due to an increase in IP 3 production.…”

Section: Discussionmentioning

confidence: 99%

Tonic Potentiation And Attenuation Produced By Membrane Depolarization In Guinea‐Pig Trachealis

Yamaki

Ogawa

Ito

2000

Clin Exp Pharma Physio

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1. We studied how membrane depolarization directly affected intracellular Ca2+ signalling when voltage-operated Ca2+ channels (VOCC) were not available in guinea-pig tracheal smooth muscle. To block VOCC, we used 3 micromol/L verapamil, which completely abolished high K+ (20-60 mmol/L)-induced contraction, and elevation of fura-2 signal. 2. Muscle tone was generated by adding Ca2+ to the extracellular Ca2+-free solution containing prostaglandin (PG)E2 (100 nmol/L) after abolishing basal tone with indomethacin (1 micromol/L). 3. In the absence of verapamil, high K+ (20-60 mmol/L) solution potentiated 2.4 mmol/l Ca2+-induced sustained contractions. Even in the presence of 3 micromol/L verapamil, replacement with 20 and 40 mmol/L K+ solution induced tonic potentiation, which was changed to attenuation with a higher K+ solution (60 mmol/L), lower extracellular Ca2+ concentration ([Ca2+]o) and pretreatment with cyclopiazonic acid (10 micromol/L), a Ca2+ sequestration inhibitor. 4. These results indicate that the balance between depolarization-dependent Ca2+ release and receptor-operated cation channel inhibition may determine whether tonic potentiation or attenuation is manifested, depending on the availability of VOCC, the magnitude of the depolarization, [Ca2+]o and Ca2+ content in the sarcoplasmic reticulum.

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Section: Discussionmentioning

confidence: 99%