Behavioral and Cardiorespiratory Responses to Bilateral Microinjections of Oxytocin into the Central Nucleus of Amygdala of Wistar Rats, an Experimental Model of Compulsion

Autor(es)

Granjeiro, Erica Maria ^[1] ; Marroni, Simone Saldanha ^[1] ; Martins Dias, Daniel Penteado ^[1] ; Heck Bonagamba, Leni Gomes ^[1] ; Costa, Kaue Machado ^[1] ; dos Santos, Jessica Cristina ^[1] ; Cortes Oliveira, Jose Antonio ^[1] ; Machado, Benedito H. ^[1] ; Garcia-Cairasco, Norberto ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Ribeirao Preto Sch Med, Dept Physiol, BR-14049 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Ribeirao Preto Sch Med, Dept Neurosci & Behav Sci, BR-14049 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 9, n. 7 JUL 18 2014.
• Citações Web of Science: 4

Resumo

Introduction: The central nucleus of amygdala plays an important role mediating fear and anxiety responses. It is known that oxytocin microinjections into the central nucleus of amygdala induce hypergrooming, an experimental model of compulsive behavior. We evaluated the behavioral and cardiorespiratory responses of conscious rats microinjected with oxytocin into the central nucleus of amygdala. Methods: Male Wistar rats were implanted with guide cannulae into the central nucleus of amygdala and microinjected with oxytocin (0.5 mu g, 1 mu g) or saline. After 24 h, rats had a catheter implanted into the femoral artery for pulsatile arterial pressure measurement. The pulsatile arterial pressure was recorded at baseline conditions and data used for cardiovascular variability and baroreflex sensitivity analysis. Respiratory and behavioral parameters were assessed during this data collection session. Results: Microinjections of oxytocin (0.5 mu g) into the central nucleus of amygdala produced hypergrooming behavior but did not change cardiorespiratory parameters. However, hypergrooming evoked by microinjections of oxytocin (1 mu g) into the central nucleus of amygdala was accompanied by increase in arterial pressure, heart rate and ventilation and augmented the power of low and high (respiratory-related) frequency bands of the systolic arterial pressure spectrum. No changes were observed in power of the low and high frequency bands of the pulse interval spectrum. Baroreflex sensitivity was found lower after oxytocin microinjections, demonstrating that the oxytocin-induced pressor response may involve an inhibition of baroreflex pathways and a consequent facilitation of sympathetic outflow to the cardiovascular system. Conclusions: The microinjection of oxytocin (1 mu g) into the central nucleus of amygdala not only induces hypergrooming but also changes cardiorespiratory parameters. Moreover, specific oxytocin receptor antagonism attenuated hypergrooming but did not affect pressor, tachycardic and ventilatory responses to oxytocin, suggesting the involvement of distinct neural pathways. (AU)

• Processo FAPESP: 07/50261-4 - Neurociências, epilepsia e arte: caracterização interdisciplinar da cepa WAR e modelos de epilepsia correlacionados: as oficinas Da Vinci, divulgação científica e quebras de estigmas em epilepsia
• Beneficiário: Norberto Garcia Cairasco
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 05/56447-7 - Pesquisa através de imagens por ressonância magnética de alto campo destinadas a estudos em humanos
• Beneficiário: João Pereira Leite
• Linha de fomento: Auxílio à Pesquisa - Programa CINAPCE - Temático
• Processo FAPESP: 06/60768-6 - Avaliação da expressão do sistema ocitocinérgico em ratos da cepa Wistar Audiogenic Rat (WAR)
• Beneficiário: Simone Saldanha Marroni
• Linha de fomento: Bolsas no Brasil - Doutorado