Abstract
Lysophosphatidic acid (LPA), the simplest of the water-soluble phospholipids, can evoke various biological responses. The present study examined the activity of LPA to induce plasma exudation and histamine release in mice. Plasma exudation was assessed by extravasation of Evans blue. Subcutaneous administration of LPA (1 – 100 μg/site) led to increased plasma exudation in the skin. The LPA-induced plasma exudation was inhibited by ketotifen, a histamine H1-receptor antagonist, and diacylglycerol pyrophosphate (DGPP), a LPA1/LPA3-receptor antagonist. Moreover, pretreatment with pertussis toxin and DGPP inhibited the histamine release from peritoneal mast cells induced by LPA. These findings indicate that plasma exudation induced by LPA is mediated by histamine release from mast cells via LPA receptor(s), presumably LPA1 and/or LPA3, coupled to Gi/o proteins. Moreover, these findings point to a role of LPA in the pathomechanisms of various allergic disorders.
