Analysis of sphingosine 1‐phosphate receptors involved in constriction of isolated cerebral arteries with receptor null mice and pharmacological tools

Abstract

Background and purpose: Sphingosine 1-phosphate (S1P) selectively and potently constricts isolated cerebral arteries, but this response has not been pharmacologically characterized. Experimental approach: The receptor subtype(s) involved in S1P-induced cerebrovascular constriction were characterized using genetic (S1P 2 and S1P 3 receptor null mice) and pharmacological tools (phospho-FTY720, a S1P 1/3/4/5 receptor agonist; SEW2871, a S1P 1 receptor agonist, JTE-013, a S1P 2 receptor antagonist, VPC23019, a S1P 1/3 receptor antagonist). Isolated basilar or peripheral (femoral, mesenteric resistance) arteries, from either rat or mouse, were studied in a wire myograph. Key results: S1P concentration-dependently constricted basilar artery in rat, wild-type (WT) and S1P 2 null mice, but barely affected vascular tone in S1P 3 null mice. Vasoconstriction to U46619 (a thromboxane analogue) or to endothelin-1 did not differ between WT, S1P 2 and S1P 3 null mice. JTE-013 inhibited not only S1P-induced vasoconstriction, but also KCl-, U46619-and endothelin-1-induced constriction. This effect was observed in WT as well as in S1P 2 null mice. VPC23019 increased the concentration-dependent vasoconstriction to S1P in both rat and mouse basilar arteries with intact endothelium, but not in rat basilar artery without endothelium. Phospho-FTY720 concentration-dependently constricted rat basilar arteries, but not femoral or mesenteric resistance arteries, while SEW2871 did not induce any response in the same arteries. Conclusions and implications: S1P constricts cerebral arteries through S1P 3 receptors. The purported S1P 2 receptor antagonist JTE-013 does not appear to be selective, at least in rodents. Enhancement of S1P-induced contraction by VPC23019 might be related to blockade of S1P 1 receptors and NO generation.

Effects of Sphingosine-1-Phosphate on Pacemaker Activity of Interstitial Cells of Cajal from Mouse Small Intestine

“…Coupled with various G-proteins, these S1P receptors mediate diverse biological actions. S1P induces contraction of rabbit gastric smooth muscle through S1P 1 and S1P 2 (Zhou and Murthy, 2004), contraction of cat esophageal smooth muscle cells through S1P 2 , contraction of cerebral arteries of mice through the S1P 3 (Salomone et al, 2008), and contraction of airway smooth muscles through the S1P 2 (Rosenfeldt et al, 2003). In the present study, treatment of ICC with S1P resulted in depolarization of the membrane and increased induction of tonic inward pacemaker currents, suggesting that S1P may mediate excitatory action on intestinal motility.…”

Sphingosine-1-phosphate and modulation of vascular tone

“…For example, S1P-induced vasoconstriction was observed in canine basilar arteries, 71 in rodent cerebral arteries, 59,60 and in mesenteric resistance arteries from aged rats. 76 In general, higher concentrations of S1P are required to elicit vasoconstriction (several 100 nanomolar to micromolar) than required for S1P-induced vasorelaxation, which typically shows an EC 50 in the low nanomolar range.…”

“…In support of this hypothesis, pharmacological as well as genetic experiments have shown that S1P 2 and/or S1P 3 receptor subtypes coupled with ROK may mediate S1P-provoked vasoconstriction in VSMCs. 60,70,77,78 It has also been shown that pharmacological inhibition of NOS activity leads to an enhancement of S1P-elicited vasoconstriction, 76,79 and conversely, S1P fails to induce vasorelaxation in eNOS null animals. 29 Further support for differential receptor-mediated vasorelaxation and vasoconstriction responses comes from studies in which S1P 1 antagonists were found to potentiate S1P-induced vasoconstriction responses in rodent cerebral arteries; however, effects of S1P 1 receptor antagonism are lost when the endothelium is removed from the blood vessel preparation.…”

“…These authors, therefore, conclude that S1P 3 subtype plays a major role to mediate constriction responses under these conditions. 60 However, Lorenz et al 61 demonstrated that S1P 2 receptor knockout mice exhibit markedly decreased mesenteric as well as renal vascular resistance, suggesting that this receptor subtype plays a key role in maintaining basal vascular tone in these organs. In addition, in isolated Hamster gracilis muscle resistance arteries, either genetic inactivation of S1P 2 subtype by transient transfection using antisense oligonucleotide or the use of a selective S1P 2 antagonist JTE-013 blunts the enhanced myogenic constriction responses elicited by S1P.…”

Les récepteurs de la sphingosine 1-phosphate

“…Les récepteurs de S1P concourent aussi à la régulation du tonus vasculaire, régulant à la fois la contraction et la relaxation des cellules musculaires lisses. Le S1P 3 [12] et le S1P 2 [13] seraient responsables de l'effet vasoconstricteur de la S1P. Le S1P 3 induit la relaxation des cellules musculaires lisses via la production de NO à partir de l'endothélium [14].…”