title: Cardiovascular anatomy and cardiac function in the air-breathing swamp eel (Monopterus albus).
abstract: Monopterus albus, a swamp eel inhabiting the freshwaters of South East Asia, relies on an extensive vascularisation of the buccal cavity, pharynx and anterior oesophagus for gas exchange, while the gills are much reduced. In the present study we describe the macro-circulation in the cephalic region and the vascularisation of the buccal cavity of M. albus using vascular fillings and micro-computed tomography (μCT). We also show that M. albus has the capacity to use the buccal cavity for aquatic gas exchange, being able to maintain normal arterial blood gas composition, blood pressure, heart rate and cardiac output throughout 10h of forced submergence. M. albus therefore can be characterised as a facultative air-breather. Because M. albus aestivates for many months in moist mud during the dry season we characterised in vivo cardiovascular function during exposure to anoxia as well as the effects of anoxia on in vitro contractility of strip preparations from atria and ventricle. Both studies revealed a low anoxia tolerance, rendering it unlikely that M. albus can survive prolonged exposure to anoxia.
authors.affiliation: Zoophysiology, Department of Biological Sciences, Aarhus University, Denmark. nina.iversen@biology.au.dk
authors.forename: Nina K
authors.initials: NK
authors.lastname: Iversen
authors.forename: Henrik
authors.initials: H
authors.lastname: Lauridsen
authors.forename: Thi Thanh Huong
authors.initials: TT
authors.lastname: Do
authors.forename: Van Cong
authors.initials: VC
authors.lastname: Nguyen
authors.forename: Hans
authors.initials: H
authors.lastname: Gesser
authors.forename: Rasmus
authors.initials: R
authors.lastname: Buchanan
authors.forename: Mark
authors.initials: M
authors.lastname: Bayley
authors.forename: Michael
authors.initials: M
authors.lastname: Pedersen
authors.forename: Tobias
authors.initials: T
authors.lastname: Wang
mesh_terms: D000222:Adaptation, Physiological; D000388:Air; D000818:Animals; D001158:Arteries / Q000033:anatomy & histology / Q000502:physiology; D001784:Blood Gas Analysis; D001794:Blood Pressure; D004848:Epithelium / Q000502:physiology / Q000648:ultrastructure; D004956:Estivation / Q000502:physiology; D005260:Female; D006257:Head / Q000033:anatomy & histology / Q000098:blood supply; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology*; D006334:Heart Function Tests / Q000379:methods*; D006339:Heart Rate; D000860:Hypoxia / Q000378:metabolism; D066298:In Vitro Techniques; D009061:Mouth Mucosa / Q000502:physiology / Q000648:ultrastructure; D009200:Myocardial Contraction; D010100:Oxygen / Q000378:metabolism; D012621:Seasons; D023701:Smegmamorpha / Q000033:anatomy & histology* / Q000502:physiology; D013045:Species Specificity
chemical_list: D010100:Oxygen