Sphingosine 1-phosphate (S1P) influences heart rate, coronary artery caliber, endothelial
integrity, and lymphocyte recirculation through five related high affinity G-protein-coupled
receptors. Inhibition of lymphocyte recirculation by non-selective S1P receptor agonists
produces clinical immunosuppression preventing transplant rejection but is associated with
transient bradycardia. Understanding the contribution of individual receptors has been
limited by the embryonic lethality of the S1P 1 knock-out and the unavailability of selective …