Pharmacology
-
Injected intrathecally, bradykinin (BK) produced either hyperalgesia (0.15 microg) or antinociception (6.0 microg) in rats when thermal noxious stimuli were used. Similarly, des-Arg(9)-BK at the lower dose (0.15 microg) decreased, whereas at the higher dose (6.0 microg) it increased the threshold to thermal noxious stimuli; however, these effects were less pronounced than those of BK. ⋯ The results obtained in this study showed that--depending on the dose used--BK and des-Arg(9)-BK could produce pro- as well as antinociceptive actions. Both B(2) and B(1) receptors are involved in the action of intrathecally applied BK.