Arterial endothelium-derived relaxing factor (AEDRF) does not suppress papillary muscle or portal vein contractions.

10(-6) M EDRF released from perfused arterial donor segments in a superfusion bioassay system, either spontaneously or stimulated by acetylcholine, did not inhibit the contractility of electrically stimulated right ventricle papillary muscle of pig, rabbit and rat. EDRF also did not inhibit spontaneously contracting rat portal vein and thus relaxed precontracted arterial rings denuded of endothelium. The results suggest that EDRF released by arterial endothelial cells is a local modulator of arterial smooth muscle and is not important for extraarterial tissue regulation.