RESUMO

Many threats exist to reptile populations, environmental pollutants being one of them. Lizards and other reptiles are usually not taken into consideration in environmental risk assessments, with the use of surrogate species for their estimates. Unfortunately, not all pesticides have the same effects in the reptile species and on these surrogates, birds and mammals, some being more toxic in lizards. This difference brings the need to evaluate their toxicity in lizards to safeguard its protection. Studies in the last decades involving contaminants' toxicity in lizard species have increased, thus we proposed to gather these information in this comprehensive review. Through searches in databases about the toxicity of pesticides in lizards, 16 scientific articles were found. Most studies investigated locomotor performance, histopathology, oxidative stress, neurotoxicology, and genetic damage from diverse pesticides with different modes of action. Progress has been made to acquire data on lizard ecotoxicology and more research is needed to cover more variables, such as studies in the embryologic stage and different pesticides.

Assuntos

RESUMO

Descreveram-se a morfologia, morfometria e ultraestrutura de segmentos das porções torácica e abdominal da aorta de quatro pacas (Cuniculus paca) adultas. Os segmentos aórticos foram analisados à microscopia de luz e à microscopia eletrônica de varredura. Mensuraram-se as espessuras do complexo formado pelas túnicas íntima e média, além da túnica adventícia. Os valores referentes à espessura do complexo formado pelas túnicas íntima e média da aorta torácica cranial foram significativamente maiores (média: 702,19µm) que os valores de outros segmentos aórticos analisados (médias: 354,18µm; 243,55µm). As camadas das paredes do vaso apresentaram variações entre si quanto à estrutura e espessura, supostamente em razão de adaptação à exigência funcional.

The aim of this study was to describe the morphology, morphometry and ultrastructure of segments of thoracic and abdominal aorta portions in four male and female paca (Cuniculus paca). Parts of the segments were examined by light microscopy and part by scanning electron microscopy. Thickness measurements of the tunica intima and media complex and tunica adventitia of the aorta were taken. In all animals the thickness values for the tunica intima and media complex of the cranial thoracic aorta were significantly higher (mean: 702.19µm) when compared to the values of other aortic segments analyzed (means: 354.18µm; 243.55µm). The layers of the vessel walls show variations in structure and thickness, presumably due to an adaptation to functionaldemand.