The role that dopamine receptors of the nucleus accumbens plays on chronic hyperalgesia

• Grant number: 10/16133-1
• Support Opportunities: Regular Research Grants
• Start date: January 01, 2011
• End date: December 31, 2012
• Field of knowledge: Biological Sciences - Physiology
• Principal Investigator: Carlos Amilcar Parada
• Grantee: Carlos Amilcar Parada
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated researchers: Claudia Herrera Tambeli

Abstract

Pain is an aversive and unpleasant perception, mediated by sensory-discriminative component that allows to identify and to locate the painful stimulus, as well as by an emotional component that involves learning, memory and reward mechanisms. Although pain has a physiological protective character well defined, in pathological cases, such as neuropathic or inflammatory pain, may have deleterious consequences for the organism, especially when it becomes chronic. The nociception modulation by the Central Nervous System (CNS) results in inhibition or facilitation of the excitability of dorsal horn neurons in the spinal cord. Although the modulation of acute pain by the CNS is relatively well described, the role that CNS plays in the development of chronic pain is not clear. The Nucleus Accumbens (NAcc) is an important structure involved in the inhibitory modulation of nociception. However, the role of NAcc plays in chronic pain has not yet known. Recently, data from our group demonstrated that, unlike the antinociception observed in acute pain, the neural activity of the NAcc is important for the maintenance of persistent inflammatory hyperalgesia (manuscript in preparation). These data suggest that the NAcc may have an important implication in the recurrence of chronic pain. However, our data did not explain which neurochemistry pathway is involved in this process. Because several studies suggest the involvement of the dopaminergic system in the modulation of pain by CNS, the goal of this study is to investigate the participation of NAcc dopaminergic pathway in facilitating the persistent hyperalgesia induced by prostaglandin E2 (PGE2) in rats. (AU)