EFFECTS OF NEWLY SYNTHESIZED AMINO-ACIDS CONTAINING THIAZOLE RESIDUESON ELECTRICALLY-EVOKED SMOOTH-MUSCLE CONTRACTIONS

New amino acids containing thiazole residues have been synthesized and in vitro experiments were performed to study their action on neurotra nsmission in target tissues with adrenergic and cholinergic neurotrans mission. Acetaminothiazoles, structurally related to the novel class, are known to act as H-1 agonists, therefore, the effects of the newly synthesized Ala-and Pro-thiazole derivatives on smooth muscle contract ile activity were compared to those of histamine (HA). The experiments were carried out on electrically stimulated prostatic part of rat and rabbit vasa deferentia and proximal guinea pig ileum. HA had biphasic effect on electrically evoked neurogenic contractions of guinea pig i leum, Pro(Thz) had a stimulating effect, while Ala(Thz) had,lo effect. The histamine H-1-receptor antagonist diphenhydramine inhibited the P ro(Thz)-induced spontaneous contractile activity in the longitudinal l ayer of guinea pig ileum. HA had a biphasic effect on electrically ind uced neurogenic contractions of rat and rabbit vasa deferentia while P ro(Thz) and Ala(Thz) inhibited rile ES-contractions. The present resul ts show that the newly synthesized compounds might affect the electric ally evoked smooth muscle contractions. Some similarity in the effects of FIA and of the new substances was observed. (C) 1998 Prous Science . All rights reserved.