| Effect of etomidate on voltage-dependent potassium currents in rat isolated hippocampal pyramidal neurons. | |
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MedLine Citation:
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PMID: 20368090 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Previous studies demonstrated general anesthetics affect potassium ion channels, which may be one of the mechanisms of general anesthesia. Because the effect of etomidate on potassium channels in rat hippocampus which is involved in memory function has not been studied, we investigated the effects of etomidate on both delayed rectifier potassium current (I(K(DR))) and transient outward potassium current (I(K(A))) in acutely dissociated rat hippocampal pyramidal neurons. METHODS: Single rat hippocampal pyramidal neurons from male Wistar rats of - 10 days were acutely dissociated by enzymatic digestion and mechanical dispersion according to the methods of Kay and Wong with slight modification. Voltage-clamp recordings were performed in the whole-cell patch clamp configuration. Currents were recorded with a List EPC-10 amplifier and data were stored in a computer using Pulse 8.5. Student's paired two-tail t test was used for data analysis. RESULTS: At the concentration of 100 micromol/L, etomidate significantly inhibited I(K(DR)) by 49.2% at +40 mV when depolarized from -110 mV (P < 0.01, n = 8), while did not affect I(K(A)) (n = 8, P > 0.05). The IC(50) value of etomidate for blocking I(K(DR)) was calculated as 5.4 micromol/L, with a Hill slope of 2.45. At the presence of 10 micromol/L etomidate, the V1/2 of activation curve was shifted from (17.3 +/- 1.5) mV to (10.7 +/- 2.9) mV (n = 8, P < 0.05), the V1/2 of inactivation curve was shifted from (-18.3 +/- 2.2) mV to (-45.3 +/- 9.4) mV (n = 8, P < 0.05). Etomidate 10 micromol/L shifted both the activation curve and inactivation curve of I(K(DR)) to negative potential, but mainly affected the inactivation kinetics. CONCLUSIONS: Etomidate potently inhibited I(K(DR)) but not I(K(A)) in rat hippocampal pyramidal neurons. I(K(DR)) was inhibited by etomidate in a concentration-dependent manner, while I(K(A)) remained unaffected. |
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Authors:
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Hong-yu Tan; Li-na Sun; Xiao-liang Wang; Tie-hu Ye |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Chinese medical journal Volume: 123 ISSN: 0366-6999 ISO Abbreviation: Chin. Med. J. Publication Date: 2010 Mar |
Date Detail:
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Created Date: 2010-04-06 Completed Date: 2010-06-29 Revised Date: 2010-09-14 |
Medline Journal Info:
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Nlm Unique ID: 7513795 Medline TA: Chin Med J (Engl) Country: China |
Other Details:
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Languages: eng Pagination: 702-6 Citation Subset: IM |
Affiliation:
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Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China. maggitan@163.com |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Anesthetics, Intravenous
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pharmacology* Animals Delayed Rectifier Potassium Channels / drug effects, physiology Etomidate / pharmacology* Male Potassium Channels / drug effects*, physiology Pyramidal Cells / drug effects*, physiology Rats Rats, Wistar |
| Chemical | |
Reg. No./Substance:
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0/Anesthetics, Intravenous; 0/Delayed Rectifier Potassium Channels; 0/Potassium Channels; 33125-97-2/Etomidate |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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