RESUMO
BACKGROUND AND PURPOSE: In the current study, we investigated the role of both kinin B1 and B2 receptors in peripheral neuropathy induced by the chronic treatment of mice with paclitaxel a widely used chemotherapeutic agent. EXPERIMENTAL APPROACH: Chemotherapy-evoked hyperalgesia was induced by i.p. injections of paclitaxel (2 mg·kg⻹) over 5 consecutive days. Mechanical and thermal hyperalgesia were evaluated between 7 and 21 days after the first paclitaxel treatment. KEY RESULTS: Treatment with paclitaxel increased both mechanical and thermal hyperalgesia in mice (C57BL/6 and CD1 strains). Kinin receptor deficient mice (B1, or B2 receptor knock-out and B1B2 receptor, double knock-out) presented a significant reduction in paclitaxel-induced hypernociceptive responses in comparison to wild-type animals. Treatment of CD1 mice with kinin receptor antagonists (DALBK for B1 or Hoe 140 for B2 receptors) significantly inhibited both mechanical and thermal hyperalgesia when tested at 7 and 14 days after the first paclitaxel injection. DALBK and Hoe 140 were also effective against paclitaxel-induced peripheral neuropathy when given intrathecally or i.c.v. A marked increase in B1 receptor mRNA was observed in the mouse thalamus, parietal and pre-frontal cortex from 7 days after the first paclitaxel treatment. CONCLUSIONS AND IMPLICATIONS: Kinins acting on both B1 and B2 receptors, expressed in spinal and supra-spinal sites, played a crucial role in controlling the hypernociceptive state caused by chronic treatment with paclitaxel.
