Neuropathic pain-like behavior after brachial plexus avulsion in mice: the relevance of kinin B1 and B2 receptors

The relevance of kinin B-1 (B1R) and B-2 (B2R) receptors in the brachial plexus avulsion (BPA) model was evaluated in mice, by means of genetic and pharmacological tools. BPA-induced hypernociception was absent in B1R, but not in B2R, knock-out mice. Local or intraperitoneal administration of the B2R antagonist Hoe 140 failed to affect BPA-induced mechanical hypernociception. Interestingly, local or intraperitoneal treatment with B1R antagonists, R-715 or SSR240612, dosed at the time of surgery, significantly reduced BPA-evoked mechanical hypernociception. Intrathecal or intracerebroventricular administration of these antagonists, at the surgery moment, did not prevent the hypernociception. Both antagonists, dosed by intraperitoneal or intrathecal routes (but not intracerebroventricularly) 4 d after the surgery, significantly inhibited the mechanical hypernociception. At 30 d after the BPA, only the intracerebroventricular treatment effectively reduced the hypernociception. A marked increase in B1R mRNA was observed in the hypothalamus, hippocampus, thalamus, and cortex at 4 d after BPA and only in the hypothalamus and cortex at 30 d. in the spinal cord, a slight increase in B1R mRNA expression was observed as early as at 2 d. Finally, an enhancement of B1R protein expression was found in all the analyzed brain structures at 4 and 30d after the BPA, whereas in the spinal cord, this parameter was augmented only at 4d. the data providenewevidence on the role of peripheral and central kinin B1R in the BPA model of neuropathic pain. Selective B1R antagonists might well represent valuable tools for the management of neuropathic pain. Univ Fed Santa Catarina, Dept Pharmacol, Ctr Biol Sci, BR-88049900 Florianopolis, SC, Brazil Pontificia Univ Catolica Rio Grande do Sul, Sch Dent, BR-90169900 Porto Alegre, RS, Brazil Universidade Federal de São Paulo, Escola Paulista Med, Dept Biophys, BR-04023900 São Paulo, Brazil Universidade Federal de São Paulo, Escola Paulista Med, Dept Biophys, BR-04023900 São Paulo, Brazil Web of Science