Caracterização citoarquitetônica e neuroquímica do sistema dopaminérgico mesencefálico de tartaruga marinha (Chelonia mydas)

• Ano de defesa: 2018
• Autor(a) principal: Siqueira, Leonardo Lucas do Nascimento
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM BIOLOGIA ESTRUTURAL E FUNCIONAL
• Palavras-chave em Português: Quelônio; Sistema nervoso; Citoarquitetura; Neurotransmissores; Dopamina; CNPQ::CIENCIAS BIOLOGICAS: BIOLOGIA ESTRUTURAL E FUNCIONAL
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/25864

Seven species of sea turtles are known in the world, among them, five species occur on the coast of Brazil: Dermochelys coriacea, Chelonia mydas, Caretta caretta, Eretmochelys imbricata and Lepidochelys olivacea. According to the Red List of the International Union for the Conservation of Nature all species of sea turtles in Brazil are threatened with extinction, with C. mydas classified as "Endangered" and E. imbricata "Critically endangered". The species C. caretta, L.olivacea and D. coriacea are classified as "Vulnerable". Little is known about the neurobiology of these animals. The dopaminergic system plays a critical role in a wide variety of functions and is present in the central nervous system of all vertebrates and is responsible for dopamine neurotransmission. Dopamine is recognized for its activity in the control of complex processes, such as motor activity programming and motivated behaviors. Understanding the importance of this neurotransmitter and the lack of studies describing the cytoarchitecture of the marine turtle brain, this research aimed to characterize for the first time the dopaminergic neuronal dopaminergic clusters of the midbrain in green turtle (C. mydas). For this, two methods were used: the Nissl method to describe the cytoarchitecture and the immunohistochemistry for TH as a way of marking DA neurons. Four C. mydas stranded specimens were used. They died at the Rehabilitation base of the Projeto Cetáceos da Costa Branca or were found dead during the monitoring of beaches between 2016 and 2017. The animals were necropsied and the brain was removed, having undergone the perfusion procedure (formalin 4%) or not (fixed in 10% formalin by immersion). After fixation, the brains were maintained in 30% sucrose until the microtomy was performed by cryostat. The prepared slides were described using an optical microscope, and images were taken through a camera coupled to the microscope. The green turtle midbrain presents a pattern of neural organization similar to that found in other reptiles. Immunoreactive DA neurons can be divided into a ventromedial group (ventral tegmental area/A10), a dorsolateral group (substantia nigra/A9) and a caudal extension of A9 (reptilian equivalent of mammalian A8/RA8). The neurons of these groups are bipolar or multipolar and ovoid, fusiform and triangular in shape. In this way, we enabled the first descriptions of the dopaminergic system that can aid in the understanding of ecological issues and provide neuroanatomic bases for future functional motor studies.