title: Coronary blood flow in the anesthetized American alligator (Alligator mississippiensis).
abstract: Coronary circulation of the heart evolved early within ectothermic vertebrates and became of vital importance to cardiac performance in some teleost fish, mammals and birds. In contrast, the role and function of the coronary circulation in ectothermic reptiles remains largely unknown. Here, we investigated the systemic and coronary arterial responses of five anesthetized juvenile American alligators (Alligator mississippiensis) to hypoxia, acetylcholine, adenosine, sodium nitroprusside, isoproterenol, and phenylephrine. We recorded electrocardiograms, monitored systemic blood pressure, blood flows in both aortae, and blood flow in a major coronary artery supplying most of the right ventricle. Coronary arterial blood flow was generally forward, but there was a brief retrograde flow during a ventricular contraction. Blood pressure was significantly changed in all conditions. Acetylcholine decreased coronary forward flow, but this response was confounded by the concomitant lowered work of the ventricles due to decreased heart rate and blood pressure. Coronary forward flow was poorly correlated with heart rate and mean arterial pressure across treatments. Overall changes in coronary forward flow, significant and not significant, were generally in the same direction as mean arterial pressure and ventricular power, approximated as the product of systemic cardiac output and mean arterial pressure.
authors.affiliation: Department of Anatomy, Embryology and Physiology, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Bjarke
authors.initials: B
authors.lastname: Jensen
authors.affiliation: Department of Biology and Environmental Science, Linnaeus University, Kalmar, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Elfwing
authors.affiliation: Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA 70643, USA.
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Elsey
authors.affiliation: Zoophysiology, Department of Bioscience, Aarhus University, Denmark.
authors.forename: Tobias
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX 76203-5017, USA.
authors.forename: Dane A
authors.initials: DA
authors.lastname: Crossley
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D000489:Alligators and Crocodiles / Q000502:physiology*; D000758:Anesthesia; D000818:Animals; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000502:physiology; D004562:Electrocardiography; D000860:Hypoxia / Q000503:physiopathology; D007545:Isoproterenol / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D009599:Nitroprusside; D010656:Phenylephrine; D000241:Adenosine; D007545:Isoproterenol; D000109:Acetylcholine
keywords: Alligator; Cardiovascular; Heart