PHARMACOLOGICAL ACTIVITIES OF A KININ RELEASED FROM RAT PLASMA BY CATHEPTIC ENZYME IN RAT STOMACH

抄録

A kinin (material c), which was different from kallidin, methionyl-lysylbradykinin (MLBK), bradykinin (BK) and neurotensin, released from rat plasma by the kinin-forming enzyme in rat stomach was pharmacologically compared with BK and histamine or serotonin (5-HT) in various in vitro and in vivo systems. Material c produced contraction of isolated rat uterus, rat fundic strip, isolated guinea-pig ileum and guinea-pig tracheal chain; increased the vascular permeability of guinea-pig skin to circulating Evans blue; and produced a fall in rabbit blood pressure. Such effects were also produced by BK, but both were clearly discriminated by their quantitatively different activities. Histamine was not effective on isolated rat uterus, isolated rat duodenum, rat fundic strip, and rabbit blood pressure; produced contraction of isolated guinea-pig ileum and guinea-pig tracheal chain; and increased the vascular permeability of guinea-pig skin; but these activities were quantitatively different from those of material c. The contraction of isolated guinea-pig ileum elicited by histamine was sustained until it was removed from the bath, but those provoked by material c and BK gradually faded. 5-HT was qualitatively different from material c and BK with respect to contracting isolated rat duodenum. 5-HT also produced contraction of isolated rat uterus and rat fundic strip and produced a fall in rabbit blood pressure, but these activities were quantitatively different from those of material c and BK. As mentioned above, material c was quantitatively and qualitatively different from histamine and 5-HT.