Influence of amygdaloid glutamatergic receptors on sensory and emotional pain-related behavior in the neuropathic rat

The role of amygdaloid glutamatergic receptors (GluRs) in maintenance of the sensory versus emotional component of neuropathic pain was studied by assessing monofilament-induced limb withdrawal response (sensory pain) and aversive place-conditioning behavior (emotional pain) following amygdaloid administration of various glutamatergic compounds in nerve-injured animals. The results indicate that endogenous activation of amygdaloid group I metabotropic GluRs, mGluR(1) and mGluR(5), and the NMDA-R contributes to maintenance of sensory and emotional components of neuropathic pain. The predominant effect by amygdaloid group I mGluRs was facilitation of emotional-like pain behavior.This study was supported by the Academy of Finland, Helsinki, Finland, the Sigrid Juselius Foundation, Helsinki, Finland, the Center for International Mobility (CIMO), Helsinki, Finland, the Portuguese Foundation for Science and Technology, Lisbon, Portugal, and the Gulbenkian Foundation, Lisbon, Portugal