Essential requirement for sphingosine kinase activity in eNOS-dependent NO release and vasorelaxation

Cellular levels of sphigosine-1-phosphate (S1P) are low and tightly regulated by sphingosine kinase (SPK). Recent studies have suggested that eNOS pathway may function as a downstream target for the receptormediated biological effects of S1P. Here we have studied the possible interplay between intracellular S1P generation and the eNOS activation pathway. Particularly by using rat aortic rings we have investigated a potential intracellular second messenger role of S1P in eNOS activation and the contribution of this alternate pathway in the control of vascular tone.