Lipopolysaccharide-Induced Sickness Behaviour Evaluated in Different Models of Anxiety and Innate Fear in Rats

Autor(es)

Bassi, Gabriel S. ^{[1, 2]} ; Kanashiro, Alexandre ^[3] ; Santin, Francele M. ^{[1, 2]} ; de Souza, Gloria E. P. ^[3] ; Nobre, Manoel J. ^{[1, 2]} ; Coimbra, Norberto C. ^{[1, 4]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Neurosci & Behav INeC, Sao Paulo - Brazil

^[2] Univ Sao Paulo FFCLRP USP, Lab Psychobiol, Sch Philosophy Sci & Literature Ribeirao Preto, Sao Paulo - Brazil

^[3] Univ Sao Paulo FCFRP USP, Sch Pharmaceut Sci Ribeirao Preto, Dept Phys & Chem, Sao Paulo - Brazil

^[4] Univ Sao Paulo FMRP USP, Lab Neuroanat & Neuropsychobiol, Dept Pharmacol, Sch Med Ribeirao Preto, BR-14049900 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: BASIC & CLINICAL PHARMACOLOGY & TOXICOLOGY; v. 110, n. 4, p. 359-369, APR 2012.
• Citações Web of Science: 46

Resumo

The fact that there is a complex and bidirectional communication between the immune and nervous systems has been well demonstrated. Lipopolysaccharide (LPS), a component of gram-negative bacteria, is widely used to systematically stimulate the immune system and generate profound physiological and behavioural changes, also known as sickness behaviour (e.g. anhedonia, lethargy, loss of appetite, anxiety, sleepiness). Different ethological tools have been used to analyse the behavioural modifications induced by LPS; however, many researchers analysed only individual tests, a single LPS dose or a unique ethological parameter, thus leading to disagreements regarding the data. In the present study, we investigated the effects of different doses of LPS (10, 50, 200 and 500 mu g/kg, i.p.) in young male Wistar rats (weighing 180200 g; 89 weeks old) on the ethological and spatiotemporal parameters of the elevated plus maze, light-dark box, elevated T maze, open-field tests and emission of ultrasound vocalizations. There was a dose-dependent increase in anxiety-like behaviours caused by LPS, forming an inverted U curve peaked at LPS 200 mu g/kg dose. However, these anxiety-like behaviours were detected only by complementary ethological analysis (stretching, grooming, immobility responses and alarm calls), and these reactions seem to be a very sensitive tool in assessing the first signs of sickness behaviour. In summary, the present work clearly showed that there are resting and alertness reactions induced by opposite neuroimmune mechanisms (neuroimmune bias) that could lead to anxiety behaviours, suggesting that misunderstanding data could occur when only few ethological variables or single doses of LPS are analysed. Finally, it is hypothesized that this bias is an evolutionary tool that increases animals security while the body recovers from a systemic infection. (AU)

• Processo FAPESP: 05/59211-4 - Estudo da resposta febril no modelo de artrite induzida por colágeno: envolvimento neural e humoral
• Beneficiário: Alexandre Kanashiro
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 09/00668-6 - Estudo do envolvimento de vias colinérgicas que conectam o núcleo tegmentar pedúnculo-pontino a núcleos monoaminérgicos do sistema endógeno de inibição de dor na analgesia pós-ictal
• Beneficiário: Norberto Cysne Coimbra
• Modalidade de apoio: Auxílio à Pesquisa - Regular