Immediate prostaglandin E2 synthesis in rat 3Y1 fibroblasts following vasopressin V1a receptor stimulation

Arginine vasopressin (AVP) induces immediate prostaglandin E2 (PGE2) production in rat 3Y1 fibroblasts. Judging from effects of several inhibitors, cytosolic phospholipase A2α (cPLA2α) and cyclooxygenase-1 (COX-1) were mainly involved in this reaction. The antagonist of vasopressin receptor V1a, and not that of V2, inhibited the AVP-induced PGE2 synthesis, indicating that AVP activates cPLA2α through V1a receptor. Treatment of 3Y1 cells with AVP resulted in transient activation of p44/42 mitogen-activated protein kinase (MAPK) and cPLA2α, and phosphatidylinositol 3-kinase (PI3K) inhibitor blocked not only AVP-induced PGE2 synthesis but also MAPK activation, suggesting that PI3K is involved in the AVP-induced MAPK and cPLA2α activation, which initiates the production of PGE2. These results suggest that PGE2 generated by the stimulation of AVP probably modulates the physiological effects of AVP.