Estudos sobre a biologia cardíaca de três espécies de morcegos neotropicais

Abstract

Bats are the only mammalian order capable of active flight, with several adaptations that permit this energetically expensive lifestyle. The Neotropics have a great diversity of bats and a variety of forms, diets, foraging habits and behaviors can be found, classified in feeding guilds. With such diversity, it is expected that the energy demands between bats of different guilds will also be different, a variety that should be reflected in their heart, an organ of central importance in vertebrate metabolism. The objective of this work was to describe and compare anatomical and physiological characteristics of the heart of three neotropical bat species with different feeding habits. To this end, aspects of the internal and external anatomy of the heart and the electrocardiogram of 25 individuals of the frugivore Artibeus lituratus, five individuals of the nectarivore Glossophaga soricina and one individual of the sangivore Desmodus rotundus were investigated. The heart of these bats have the general anatomical and physiological characteristics of the mammal heart, with some specific differences between these three species, in relation to other bats and in relation to other mammals described in the literature. The differences between the three species are linked to body weight and cardiac anatomy. Among the anatomical features are the extensive set of pericardial ligaments, the presence of the valve of Thebesius, the variable number of leaflets of the right atrioventricular valve and the variable number of papillary muscles in the right ventricle. Among the characteristics of the electrocardiogram are the high heart rates, the differences in the duration of the PR and QT intervals, the differences in the amplitudes of the R and T waves and the absence of the ST segment. The three species included in this study do not present differences related to their lifestyles, which indicates the efficiency of the mammalian heart, an evolutionarily conserved organ, in promoting the blood circulation of animals with a high metabolic rate and with a very diverse range of life styles.