α-adrenergic activation of the muscarinic K+ channel is mediated by arachidonic acid metabolites

Phenylephrine (10 microM), added in the bathing solution, stimulated the cardiac muscarinic K+ channel (IK.ACh) in the cell-attached patch. The pipette solution contained 10 microM atropine and 100 microM theophylline to block the muscarinic acetylcholine and adenosine receptors, respectively. The c...

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Bibliographic Details
Published in:Pflügers Archiv 1989-05, Vol.414 (1), p.102-104
Main Authors: KURACHI, Y, ITO, H, SUGIMOTO, T, SHIMIZU, T, MIKI, I, UI, M
Format: Article
Language:English
Subjects:
Animals
Arachidonate Lipoxygenases - antagonists & inhibitors
Arachidonic Acid
Arachidonic Acids - metabolism
Biological and medical sciences
Cyclooxygenase Inhibitors
Fundamental and applied biological sciences. Psychology
Guinea Pigs
Heart
In Vitro Techniques
Lipoxygenase Inhibitors
Myocardium - cytology
Phenylephrine - pharmacology
Potassium Channels - drug effects
Vertebrates: cardiovascular system
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Description
Summary:Phenylephrine (10 microM), added in the bathing solution, stimulated the cardiac muscarinic K+ channel (IK.ACh) in the cell-attached patch. The pipette solution contained 10 microM atropine and 100 microM theophylline to block the muscarinic acetylcholine and adenosine receptors, respectively. The channel activation induced by phenylephrine was blocked by prazosin, an alpha 1-antagonist, indicating that alpha 1-adrenergic receptor mediates the response. Phenylephrine-induced activation was prevented by nordihydroguaiaretic acid, a lipoxygenase inhibitor, and AA-861, a 5-lipoxygenase inhibitor, but was not affected by indomethacin, a cyclooxygenase inhibitor. These observations suggest that 5-lipoxygenase metabolites of arachidonic acid may be involved in the alpha-adrenergic activation of IK.ACh.
ISSN:0031-6768
1432-2013
DOI:10.1007/BF00585635