Receptors for substance P.I. The pharmacological preparations

摘要: The undecapeptide substance P (SP) is both a potent stimulant of intestinal (guinea pig ileum), vascular venous (rabbit mesenteric vein) and tracheal trachea) smooth muscles, relaxant large arteries (dog common carotid artery, rabbit aorta). SP also decreases the peripheral resistance in coronary vessels isolated hearts. contractions guinea ileum response to are partially antagonised by atropine significantly depressed indomethacin, while trachea strongly potentiated indomethacin. Large arteries, but not veins, insensitive when endothelium removed, slightly less responsive peptide this applied presence mepacrine, eicosatetraynoid acid or BW 755C. These results indicate that all myotropic actions SP, except on muscle, completely indirect most them due release endogenous agents: these acetylcholine, prostaglandins possibly histamine ileum, leukotriene still unidentified factor endothelial origin dog arteries. effect anterior vein appears be direct one.