Panicolytic-like action of bradykinin in the dorsal periaqueductal gray through μ-opioid and B2-kinin receptors.
BACKGROUND The effect of small and high doses of intracerebroventricularly (icv) applied bradykinin (BK) on nociception produced by mechanical stimuli and the participation of B1 and B2 receptors in this nociception were investigated in rats. RESULTS BK at the lowest dose (0.06 μg) produced hyperalgesia whereas at the higher doses (6 and 12 μg) antinociception. This effect was abolished by B1 or B2 receptor antagonists, des-Arg(10)-HOE140 and HOE140 (1 pmol icv), respectively. CONCLUSION Depending on the dose used, BK produces pro- or anti-nociceptive action. Both B1 and B2 receptors are involved in the action of icv applied BK.