Inositol 1,4,5-Trisphosphate-Induced Ca2+-Transient and Outward K+ Current in Single Smooth Muscle Cells of Guinea Pig Small Intestine.
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- Ito Shigeo
- Department of Pharmacology and Clinical Pharmacology, St. George''s Hospital Medical School
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- Bolton Thomas B.
- Department of Pharmacology and Clinical Pharmacology, St. George''s Hospital Medical School
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Abstract
The effects of inositol 1, 4, 5-trisphosphate (InsP3) released from caged InsP3 by flash photolysis on free intracellular Ca2+ concentration, [Ca2+]i, and outward K+ current were simultaneously examined in a single smooth muscle cell of guinea pig small intestine using a patch pipette solution containing Indo-1 (0.1 mM), caged InsP3 (50 μM) and KCl (130 mM). At a holding potential of −50 mV, a depolarizing pulse to + 10 mV for 200 msec caused a transient Ca2+ current and an increase in [Ca2+]i. The amplitude of the Ca2+-transient was positively correlated with the peak Ca2+ current and negatively correlated with resting [Ca2+]i. InsP3 produced increases in [Ca2+]i and outward K+ current in most of the cells at −50 and −30 mV. The outward K+ current response reached a peak sooner and decayed more quickly than the Indo-1 signal. Both responses to InsP3 were resistant to the removal of extracellular Ca2+. The Ca2+-transient and outward K+ current responses to InsP3 at −30 mV were larger than those at −50 mV. The InsP3-induced Ca2+-transient was increased by increasing resting [Ca2+]i at −30 mV but not at −50 mV. These results suggest that InsP3-induced Ca2+ release from stores is potentiated by slight increases in [Ca2+]i via membrane depolarization.
Journal
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- The Japanese Journal of Pharmacology
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The Japanese Journal of Pharmacology 71 (1), 1-10, 1996
The Japanese Pharmacological Society
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Details 詳細情報について
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- CRID
- 1390282679264597888
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- NII Article ID
- 10008188141
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- NII Book ID
- AA00691188
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- DOI
- 10.1254/jjp.71.1
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- COI
- 1:CAS:528:DyaK28XjtF2msL0%3D
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- ISSN
- 13473506
- 00215198
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- PubMed
- 8791166
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- Text Lang
- en
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- Data Source
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- JaLC
- Crossref
- PubMed
- CiNii Articles
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- Abstract License Flag
- Disallowed