Structural requirements for charged lipid molecules to directly increase or suppress K+ channel activity in smooth muscle cells. Effects of fatty acids, lysophosphatidate, acyl coenzyme A and sphingosine
Document Type
Journal ArticlePublication Date
1994-03-01Keywords
Acyl Coenzyme A; Amines; Animals; Bufo marinus; Cell Separation; Electrochemistry; Electrophysiology; Fatty Acids; Lipid Bilayers; Lipids; Lysophospholipids; Muscle, Smooth; Potassium Channels; SphingosineLife Sciences
Medicine and Health Sciences
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Show full item recordAbstract
We determined the structural features necessary for fatty acids to exert their action on K+ channels of gastric smooth muscle cells. Examination of the effects of a variety of synthetic and naturally occurring lipid compounds on K+ channel activity in cell-attached and excised membrane patches revealed that negatively charged analogs of medium to long chain fatty acids (but not short chain analogs) as well as certain other negatively charged lipids activate the channels. In contrast, positively charged, medium to long chain analogs suppress activity, and neutral analogs are without effect. The key requirements for effective compounds seem to be a sufficiently hydrophobic domain and the presence of a charged group. Furthermore, those negatively charged compounds unable to "flip" across the bilayer are effective only when applied at the cytosolic surface of the membrane, suggesting that the site of fatty acid action is also located there. Finally, because some of the effective compounds, for example, the fatty acids themselves, lysophosphatidate, acyl Coenzyme A, and sphingosine, are naturally occurring substances and can be liberated by agonist-activated or metabolic enzymes, they may act as second messengers targeting ion channels.Source
J Gen Physiol. 1994 Mar;103(3):471-86.
DOI
10.1085/jgp.103.3.471Permanent Link to this Item
http://hdl.handle.net/20.500.14038/34335PubMed ID
8195783Related Resources
ae974a485f413a2113503eed53cd6c53
10.1085/jgp.103.3.471