| Calcium and sodium dependence of the biphasic response of the guinea-pig ileum to agonists. | |
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MedLine Citation:
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PMID: 4054215 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The isometric responses of the longitudinal smooth muscle of the guinea-pig ileum to acetylcholine and to histamine consist of a phasic contraction followed by a fade and a tonic contraction. At high agonist concentrations the fade is more pronounced and a period of lower tonus is observed in the early stage of the tonic component of the response. Experiments done in Ca2+-free medium indicate that the events responsible for the shape of the response take place in the absence of Ca2+ and of contraction. The phasic contraction was inhibited by hyperpolarization in low-Na+ medium. Small decreases in the external Na+ concentration caused a diminution of the fade. Reduction of the Na+ concentration during the early stages of the tonic response caused contraction whereas relaxation was observed at the late stages. It is proposed that the fade is dependent on a Na+-sensitive mechanism that is predominant at early but not at late stages of the responses to agonists. |
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Authors:
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V L Nouailhetas; S I Shimuta; A C Paiva; T B Paiva |
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Publication Detail:
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Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: European journal of pharmacology Volume: 116 ISSN: 0014-2999 ISO Abbreviation: Eur. J. Pharmacol. Publication Date: 1985 Oct |
Date Detail:
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Created Date: 1985-12-18 Completed Date: 1985-12-18 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 1254354 Medline TA: Eur J Pharmacol Country: NETHERLANDS |
Other Details:
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Languages: eng Pagination: 41-7 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acetylcholine
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pharmacology Animals Calcium / physiology* Female Guinea Pigs Histamine / pharmacology Ileum / drug effects Isometric Contraction / drug effects Male Membrane Potentials / drug effects Muscle Contraction / drug effects Muscle, Smooth / drug effects* Potassium / pharmacology Sodium / physiology* Time Factors |
| Chemical | |
Reg. No./Substance:
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51-45-6/Histamine; 51-84-3/Acetylcholine; 7440-09-7/Potassium; 7440-23-5/Sodium; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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