Modificações do coração durante o desenvolvimento pós-embrionário de Aedes aegypti

• Autor(a) principal: Leódido, Ana Carolina Machado
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2346
• topic: Aedes aegypti; Coração; Mosquito; Aedes aegypti; Heart; Mosquito; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

The heart of insects consists of a mid-dorsal vessel that extends along their abdomen length and is responsible for pumping the haemolymph. In spite of this importance for insect homeostasis, the morphology of the insect heart, specifically in Culicidae, is still unexplored. This study aimed to investigate the morphological changes of the heart of Aedes aegypti during the post-embryonic development (including larvae [L4] and pupa and adult females) through using a combination of light, confocal and scanning and transmission electron microscopies. In all studied stages the heart is a tubular-shaped organ, consisting of striated muscle in helical arrangement. The organ is divided into chambers or compartments, in which each one has a pair of ostia. However, in L4 and pupa the ostia are simple openings in the heart wall, while in the adult have a valve-like structure. The heart of mosquito is physically associated with polinucleated alary muscle fibers and pericardial cells. The formers occur in pairs and form branches that include pericardial cells inside them and anastomose above heart surface, and these branches are more developed in adults. The heart ventral surface is wrinkled in L4, while in adults it has longitudinal depressions. The cell membrane of the cardiac muscle has invaginations forming the T tubules and their cytoplasm is almost entirely filled by sarcomeres delimited by discontinuous Z lines, while mitochondria are located mainly in the cell periphery. The pericardial cells are rounded and have a heterogeneous cytoplasm, with electron-dense structures resembling lysosomes that are more abundant and prominent in pupae. In these cells, vacuoles with heterogeneous content and several cell membrane invaginations are also observed in all developmental stages. In the present study we pointed some morphological changes of the heart during the post-embryonic development of the yellow fever mosquito. They include changes in the heart surface and the arising of valves and well-developed alary fiber ramifications in the adult females. In this work we show that the heart of A. aegypti is not rebuilt during metamorphosis, unlike other visceral organs. Moreover, the pericardial cells of A. aegypti undergo changes during the post-embryonic development, that include the increase of the cytoplasm and cell inclusions. These new data contribute to our understanding of A. aegypti heart and to an improved general understanding of mosquito biology and circulatory system.