Interaction between Flow-Induced Prostacyclin Production and Nitric Oxide Synthesis in Vascular Smooth Muscle Cells

Abstract

The interaction between flow-induced prostacyclin production and nitric oxide (NO) synthesis in vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) was studied. Flow was made by 3cm-amplitude horizontal shaking at various frequencies at 37 °C under 5% CO₂ and 95% air. Basal prostacyclin and NO production rates did not differ between strains. Prostacycnm production during flow was significantly greater with increasing shear stress from shaking frequencies of 120/min to 180/min, and was greater in SHR than in WKY. In contrast, flow-induced NO production was greater in WKY than in SHR. The addition of N nitro-L-arginine further increased the flow-induced increase in the production of prostacyclin in WKY in a dose-dependent manner, but had no effects in SHR. Indomethacin did not affect flow-induced NO production in either strain. We conclude that increases in prostacyclin production in SHR-derived VSMC during shear stress may be due to decreases in the suppression by NO and may compensate for hypertension. (Hypertens Res 1994; 17: 227-232)