Bradykinin contributes to nociception in periphery by activating and sensitizing nociceptor neurons and in the spinal cord by promoting central sensitization (see Kohno et al SFN Abstracts 2003). Peripheral sensitization is mediated by local release of kinins and prostanoids that produce post-translational changes in pain transducers (e.g. TRPV1) and voltage-gated sodium channels, and central sensitization by phosphorylation of NMDA and AMPA receptors. Bradykinin in non-inflamed animals acts primarily on the constitutively expressed B2 G-protein coupled receptor. We have now examined the localization of the B2 bradykinin receptor in rat DRG and spinal cord using immunohistochemistry and in situ hybridization. The B2 receptor is widely expressed in both these tissues, only in neurons. In the DRG B2 is present in both peripherin positive and negative neurons. The B2 receptor also co-localizes with TRPV1 and CGRP in the DRG, and in central afferent terminals in the dorsal horn. B2 is expressed in many neurons...