The role of central serotonin modulating mechanical and thermal nociception during systemic inflammation

• Grant number: 17/04644-0
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): June 01, 2017
• Effective date (End): May 31, 2018
• Field of knowledge: Biological Sciences - Physiology
• Principal Investigator: Luiz Guilherme de Siqueira Branco
• Grantee: Caroline Rodrigues dos Santos
• Home Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 16/17681-9 - Pathophysiological changes during systemic inflammation, AP.TEM

Abstract

The Central Nervous System (CNS) is able to provide fundamental adaptive responses during challenges, such as diseases, traumas and noxius stimuli. Administration of lipopolysaccharide (LPS - a component of gram-negative bacteria membrane) induces systemic inflammation and this has been universally accepted as an excellent model to study physiopathological responses observed during infection. These responses are centrally mediated and triggered by inflammatory molecules produced peripherally. Inflammation also influences the perception of nociception, presenting itself as a complex and dynamic response. Serotonin (5-HT) is one of the neurotransmitters involved in nociceptive pathways in several regions of the CNS. Our hypothesis is that central serotonin plays an antinociceptive role in mechanical and thermal nociception during systemic inflammation. Thus, the present study will investigate the role of central serotonin in mechanical and thermal nociception during LPS-induced systemic inflammation. For this purpose, Wistar rats will be submitted to cannulation of the third cerebral ventricle (icv). Seven days later, the animals will be acclimatized for two days in the mechanical allodynia or thermal hyperalgesia test apparatus in order to reduce stress during the experimental period. Afterward, baseline behavioral tests will be performed and in the following day, icv microinjection of serotonin or vehicle will be performed followed by an intraperitoneal (ip) injection of LPS or saline 30 min later than the icv microinjection. Evaluations will be performed 15, 30, 45, 60 and 120 min after the ip injection. Thus, our main goal is to investigate the role of central serotonin in modulating behavior against nociceptive tests during systemic inflammation, enabling a better understanding of neuroimmune and behavioral interactions. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MOTA, CLARISSA M. D.; RODRIGUES-SANTOS, CAROLINE; CAROLINO, RUITHER O. G.; ANSELMO-FRANCI, JANETE A.; BRANCO, LUIZ G. S. Citral-induced analgesia is associated with increased spinal serotonin, reduced spinal nociceptive signaling, and reduced systemic oxidative stress in arthritis. Journal of Ethnopharmacology, v. 250, MAR 25 2020. Web of Science Citations: 1.