A NOVEL SYNTHETIC PHYLLOLITORIN ANALOG [DESTRP(3),LEU(8)]PHYLLOLITORIN INHIBITS SCRATCHING BEHAVIOR INDUCED BY NEUROMEDIN-C IN RATS

[DesTrp(3),Leu(8)]phyllolitorin (DTP) (pGlu-Leu-Ala-Val-GIy-Ser-Leu-Me t-NH2) was synthesized as an analogue of phyllolitorins, a new member of bombesin family, and examined if it antagonized neuromedin C (NMC)- induced scratching. DTP inhibited dose-dependently the scratching beha vior by NMC (1 mu g), whereas it did not alter any element of other gr ooming behaviors. DTP (6 mu g)alone was found to be neither toxic nor active in inducing both scratching and grooming, which were comparable to vehicle alone. Assuming that the scratching behavior is commonly a nd specifically elicited by bombesin family peptides, DTP might be cla ssified as a new type of bombesin antagonist.