Efeitos da administração repetida de ayahuasca no comportamento e na expressão de c-Fos em ratos expostos ao campo aberto

• Autor(a) principal: Daldegan-Bueno, Dimitri Henriques [UNIFESP]
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.xhtml?popup=true&id_trabalho=9274964; https://repositorio.unifesp.br/handle/11600/58768
• topic: Ayahuasca; c-Fos; Open-field; Amygdala; Anxiety; Ethogram; Ayahuasca; c-Fos; Amígdala; Teste de campo aberto; Ansiedade; Etograma

Objective: To evaluate the behavioural and neurobiological effects of repeated ayahuasca administration in an animal model of exploratory behaviour related to novelenvironment anxiety. Method: Male Wistar rats received 120, 240, 480, 3,600mg/kg of resuspended lyophilised ayahuasca or water by gavage once a day for 30 days; there was also a non-manipulated homecage group. On the 1st and 15th day, animals were placed individually for five minutes into an acrylic cage for behavioural assessment; on the 30th day, animals were placed individually in the open field for 20 minutes, followed by brain perfusion and removal (140min after last ayahuasca administration) for c-Fos immunoreactive analysis. All tests were done 60 minutes after the administration of ayahuasca. A stochastic analysis based on the ethogram of the animals were conducted to analyse the sequential structure of behaviours; weight was recorded during the entire process. Results: Acute low dose (120mg/kg) did not affect the behaviour but when administered repeatedly increased the ambulation and vertical exploration in the open field, while intermediate doses (240 and 480mg/kg) did not affect the behaviour either acutely nor repeatedly. Extreme high dose (3,600mg/kg) decreased vertical exploration both acutely and repeatedly, and animals in this group had a lower weight gain when compared to all groups, possibly due to the adverse effects that ayahuasca may induce; ethological analysis based on the ethogram confirmed these behavioural results. Aya3,600 had more c-Fos expression than water and aya120 in the medial CA1 region of the hippocampus; more expression than homecage, water, and aya120 in the anterior CA3 region of the hippocampus, and more expression than homecage and water in the medial infra-limbic cortex region. On the aya120 group, there was a negative correlation between the medial CA1 of the hippocampus and ambulation, time spent in rearing and a positive correlation between the medial CA1 and freezing behaviour; for aya3,600 there was a negative correlation between the anterior CA3 and time spent in rearing. No behavioural or neurobiological effects related to anxiety assessed by the open field were found. Conclusion: Different doses of repeated administration of ayahuasca have different effects on the exploratory behaviour evaluated by the open field; however, it did not alter the sequential structure of exploratory behaviour, even with an extremely high dose. Higher activation of areas involved in the emotional process and serotonergic pathway add relevant material to the neurobiological literature of ayahuasca - specifically regarding the repeated/chronic ingestion. Extreme high doses of ayahuasca, even when administrated for 30 consecutive days, does not cause severe impairment in rats, providing further data regarding the safety of ayahuasca intake. Finally, our data do not support an anxiolytic effect of repeated ayahuasca related to the exploration of new anxiogenic-environment.