Effects of Sphingosine 1-Phosphate, a Naturally Occurring Biologically Active Lysophospholipid, on the Rat Cardiovascular System

Abstract

Recent studies have indicated that sphingosine 1-phosphate(Sph-1-P)is released into the blood flow from activated platelets upon stimulation to exhibit a wide spectrum of biological functions.The purpose of the present study was to assess the acute cardiovascular effects of circulating Sph-1-P in the in vivo rat model.Intravenous administration of Sph-1-P decreased the heart rate, ventricular contraction and blood pressure, while it hardly affected the atrioventricular and intraventricular conduction.Sph-1-P did not affect the adenylate cyclase activities of the membrane preparations made from the right atrium and left ventricle.These results suggest that functional receptors like lysophospholipid receptor Edg-1, which can inhibit adenylate cyclase via G_i protein, are lacking in the rat heart.Moreover, these observations will provide a clue to better understand the various types of Sph-1-P-related pathophysiological processes.