Document Detail


The endogenous brain constituent N-arachidonoyl L-serine is an activator of large conductance Ca2+-activated K+ channels.
MedLine Citation:
PMID:  18923087     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The novel endocannabinoid-like lipid N-arachidonoyl L-serine (ARA-S) causes vasodilation through both endothelium-dependent and -independent mechanisms. We have analyzed the vasorelaxant effect of ARA-S in isolated vascular preparations and its effects on Ca(2+)-activated K(+) currents in human embryonic kidney cells stably transfected with the alpha-subunit of the human, large conductance Ca(+)-activated K(+) (BK(Ca)) channel [human embryonic kidney (HEK) 293hSlo cells]. ARA-S caused relaxation of rat isolated, intact and denuded, small mesenteric arteries preconstricted with (R)-(-)-1-(3-hydroxyphenyl)-2-methylaminoethanol hydrochloride (pEC(50), 5.49 and 5.14, respectively), whereas it caused further contraction of vessels preconstricted with KCl (pEC(50), 5.48 and 4.82, respectively). Vasorelaxation by ARA-S was inhibited by 100 nM iberiotoxin. In human embryonic kidney cells stably transfected with the alpha-subunit of the human BK(Ca) channel cells, ARA-S and its enantiomer, N-arachidonoyl-D-serine, enhanced the whole-cell outward K(+) current with similar potency (pEC(50), 5.63 and 5.32, respectively). The potentiation was not altered by the beta(1) subunit or mediated by ARA-S metabolites, stimulation of known cannabinoid receptors, G proteins, protein kinases, or Ca(2+)-dependent processes; it was lost after patch excision or after membrane cholesterol depletion but was restored after cholesterol reconstitution. BK(Ca) currents were also enhanced by N-arachidonoyl ethanolamide (pEC(50), 5.27) but inhibited by another endocannabinoid, O-arachidonoyl ethanolamine (pIC(50), 6.35), or by the synthetic cannabinoid O-1918 [(-)-1,3-dimethoxy-2-(3-3,4-trans-p-menthadien-(1,8)-yl)-orcinol] (pIC(50), 6.59), which blocks ARA-S-induced vasodilation. We conclude the following. 1) ARA-S directly activates BK(Ca) channels. 2) This interaction does not involve cannabinoid receptors or cytosolic factors but is dependent on the presence of membrane cholesterol. 3) Direct BK(Ca) channel activation probably contributes to the endothelium-independent component of ARA-S-induced mesenteric vasorelaxation. 4) O-1918 is a BK(Ca) channel inhibitor.
Authors:
Grzegorz Godlewski; László Offertáler; Douglas Osei-Hyiaman; Fong Ming Mo; Judith Harvey-White; Jie Liu; Margaret I Davis; Li Zhang; Raj K Razdan; Garry Milman; Pal Pacher; Partha Mukhopadhyay; David M Lovinger; George Kunos
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Intramural     Date:  2008-10-15
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  328     ISSN:  1521-0103     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  2009 Jan 
Date Detail:
Created Date:  2008-12-19     Completed Date:  2009-02-03     Revised Date:  2012-03-07    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  United States    
Other Details:
Languages:  eng     Pagination:  351-61     Citation Subset:  IM    
Affiliation:
Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Bethesda, MD 20892-9413, USA. godlewskig@mail.nih.gov
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MeSH Terms
Descriptor/Qualifier:
Alternative Splicing
Animals
Arachidonic Acids / physiology*
Brain / physiology*
Cell Line
Genetic Variation
Humans
Kidney / enzymology
Large-Conductance Calcium-Activated Potassium Channels / genetics,  physiology*
Male
Membrane Potentials / physiology
Patch-Clamp Techniques
Rats
Rats, Sprague-Dawley
Serine / analogs & derivatives*,  physiology
Grant Support
ID/Acronym/Agency:
Z01 AA000375-02/AA/NIAAA NIH HHS; Z99 AA999999/AA/NIAAA NIH HHS
Chemical
Reg. No./Substance:
0/Arachidonic Acids; 0/Large-Conductance Calcium-Activated Potassium Channels; 0/N-arachidonoyl L-serine; 56-45-1/Serine
Comments/Corrections

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