Interaction between anandamide and sphingosine-1-phosphate in mediating vasorelaxation in rat coronary artery.
OBJECTIVE
Anandamide and sphingosine-1-phosphate (S1P) both regulate vascular tone in a variety of vessels. This study aimed to examine the mechanisms involved in the regulation of coronary vascular tone by anandamide and S1P, and to determine whether any functional interaction occurs between these receptor systems.


METHODS
Mechanisms used by anandamide and S1P to regulate rat coronary artery (CA) reactivity were investigated using wire myography. Interactions between S1P and the cannabinoid (CB)(2) receptor were determined using human embryonic kidney 293 (HEK293) cells that stably over-express recombinant CB(2) receptor.


RESULTS
Anandamide and S1P induced relaxation of the rat CA. CB(2) receptor antagonists attenuated anandamide-induced relaxation, while S1P-mediated relaxation was dependent on the vascular endothelium and S1P(3). Anandamide treatment resulted in an increase in the phosphorylation of sphingosine kinase-1 within the CA. Conversely, anandamide-mediated relaxation was attenuated by inhibition of sphingosine kinase. Moreover, S1P(3), specifically within the vascular endothelium, was required for anandamide-mediated vasorelaxation. In addition to this, S1P-mediated relaxation was also reduced by CB(2) receptor antagonists and sphingosine kinase inhibition. Further evidence that S1P functionally interacts with the CB(2) receptor was also observed in HEK293 cells over-expressing the CB(2) receptor.


CONCLUSIONS
In the vascular endothelium of rat CA, anandamide induces relaxation via a mechanism requiring sphingosine kinase-1 and S1P/S1P(3). In addition, we report that S1P may exert some of its effects via a CB(2) receptor- and sphingosine kinase-dependent mechanism, where subsequently formed S1P may have privileged access to S1P(3) to induce vascular relaxation.
Mair
K M
KM
Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK. k.mair@bio.gla.ac.uk
Robinson
E
E
Kane
K A
KA
Pyne
S
S
Brett
R R
RR
Pyne
N J
NJ
Kennedy
S
S
D000818:Animals; D001095:Arachidonic Acids / Q000008:administration & dosage / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology; D002317:Cardiovascular Agents / Q000008:administration & dosage / Q000494:pharmacology; D002460:Cell Line; D003331:Coronary Vessels / Q000502:physiology*; D013759:Dronabinol / Q000031:analogs & derivatives / Q000494:pharmacology; D063388:Endocannabinoids; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007213:Indomethacin / Q000008:administration & dosage / Q000494:pharmacology; D008246:Lysophospholipids / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D053284:Polyunsaturated Alkamides / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043885:Receptor, Cannabinoid, CB2 / Q000037:antagonists & inhibitors; D013110:Sphingosine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D014664:Vasodilation
D001095:Arachidonic Acids; D002121:Calcium Channel Blockers; D002317:Cardiovascular Agents; C469526:Cnr2 protein, rat; D063388:Endocannabinoids; D007211:Indoles; D008246:Lysophospholipids; D053284:Polyunsaturated Alkamides; D043885:Receptor, Cannabinoid, CB2; C060506:sphingosine 1-phosphate; D013759:Dronabinol; D013110:Sphingosine; C062018:HU 211; C094023:iodopravadoline; C078814:anandamide; D007213:Indomethacin