[Induction of bradykinin B1 receptor in rats]

We found the time-dependent induction of the systemic hypotensive response to des-Arg9-bradykinin and the contractile response of ileum of rats to des-Arg9-bradykinin. Both induced responses to des-Arg9-bradykinin were inhibited by treatment with a B1 receptor competitive antagonist, while the responses to bradykinin was constant throughout the experiment and was not influenced by the B1 antagonist, suggesting that these responses occur via a B1 receptor. The potencies of des-Arg9-bradykinin in these responses were comparable to those of bradykinin at a molar base. The other characteristics of this phenomenon is that several hours were required to the induction of these responses. In a case of hypotensive response, intravenous LPS pretreatment was necessary, but not for the induction of contraction in ileum preparation. Treatment with actinomycin D or cycloheximide throughout the experiment suppressed the induction of the contractile response to des-Arg9-bradykinin. The expression of B1 receptor gene was also confirmed by a RT-PCR method. Therefore, we concluded that these responses to des-Arg9-bradykinin occurred via a B1 receptor, which could be newly generated time-dependently.