Abstract
Using a rat formalin-induced conditioned place avoidance (F-CPA) model and Fos immunohistochemistry, the present study observed the effect of N-methyl- d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-isoxozole propionic acid/kainite (AMPA/KA) receptors on pain-related aversion. Adult Sprague–Dawley rats were implanted with cannula in the anterior cingulate cortex (ACC) or the lateral ventricle. Before (10 min) the injection of formalin into a hindpaw on days 2 and 4 of place-conditioning trials, vehicle (0.01 M PBS), the NMDA receptors antagonist, 2-amino-5-phosphonovalerate (AP5), or the AMPA/KA receptors antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX), was injected through the cannula. F-CPA was effectively eliminated by both intracerebroventricular (icv) and intra-ACC microinjection of AP5. In contrast, the intra-ACC or icv injection of DNQX failed to alter the conditioning scores of F-CPA compared with vehicle control group ( P > 0.05). Intra-ACC or icv injection of AP5 or DNQX had no effect on formalin-induced acute nociceptive behaviors. Fos immunoreactivity in the ACC was activated by retrieval of pain-related aversion, and this activation was significantly suppressed by preadministration of AP5, but not DNQX ( P < 0.001). These results suggest that NMDA receptors in the ACC are preferentially involved in the processing of the affective dimension of pain.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.