| A patch clamp study of muscarinic excitation of the rat adrenal chromaffin cells. | |
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MedLine Citation:
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PMID: 2213565 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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A patch clamp study was performed to determine the ionic mechanisms underlying the muscarinic excitation of rat adrenal chromaffin cells. Burst-like, single-channel currents with brief openings were recorded during cell-attached or cell-free patch recording when the pipette solution contained high K+ media (70-140 mM), and the currents were recorded at potentials near the resting membrane potential. The amplitude and frequency of channel openings were dependent on the membrane potential and the K+ concentration of the external medium. Moreover, the single-channel currents observed with high K+ outside the membrane during inside-out recording were suppressed by the addition of a K+ channel blocker, tetraethylammonium, inside the membrane. These results suggest that the single K+ currents recorded in the present study had properties similar to those of the resting or muscarine-activated K+ currents in atrioventricular cells of the rabbit heart. During cell-attached patch recording with the high K+ medium in the recording pipette, muscarine at concentrations of 10(-5) to 10(-4) M dose dependently decreased the frequency of the channel openings but did not affect the current-voltage relationship or the time constants of open and close time histograms. These results indicate that muscarinic-induced suppression of K+ currents is caused by a decrease in the number of active K+ channels at the resting membrane potential. |
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Authors:
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A Akaike; Y Mine; M Sasa; S Takaori |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The Journal of pharmacology and experimental therapeutics Volume: 255 ISSN: 0022-3565 ISO Abbreviation: J. Pharmacol. Exp. Ther. Publication Date: 1990 Oct |
Date Detail:
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Created Date: 1990-11-21 Completed Date: 1990-11-21 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0376362 Medline TA: J Pharmacol Exp Ther Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 340-5 Citation Subset: IM |
Affiliation:
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Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Chromaffin Granules / physiology* Female Membrane Potentials / drug effects Muscarine / pharmacology Potassium / pharmacology Potassium Channels / drug effects, physiology* Rats Receptors, Muscarinic / physiology* Tetraethylammonium Compounds / pharmacology Tetrodotoxin / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Potassium Channels; 0/Receptors, Muscarinic; 0/Tetraethylammonium Compounds; 300-54-9/Muscarine; 4368-28-9/Tetrodotoxin; 7440-09-7/Potassium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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