title: Autonomic control of the heart in the Asian swamp eel (Monopterus albus).
abstract: The Asian swamp eel (Monopterus albus) is an air-breathing teleost with very reduced gills that uses the buccal cavity for air-breathing. Here we characterise the cardiovascular changes associated with the intermittent breathing pattern in M. albus and we study the autonomic control of the heart during water- and air-breathing. The shift from water- to air-breathing was associated with a rise in heart rate from 27.7 ± 1.6 to 41.4 ± 2.6 min(-1) and an increase in cardiac output from 23.1 ± 3.0 to 58.7 ± 6.5 mLmin(-1)kg(-1), while mean systemic blood pressure did not change (39.0 ± 3.5 and 46.4 ± 1.3 cmH(2)O). The autonomic control of the heart during water- and air-breathing was revealed by infusion of the β-adrenergic antagonist propranolol and muscarinic antagonist atropine (3 mgkg(-1)) in eels instrumented with an arterial catheter. Inhibition of the sympathetic and parasympathetic innervations of the heart revealed a strong vagal tone on the heart of water-breathing eels and that the tachycardia during air-breathing is primarily mediated by withdrawal of cholinergic tone.
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: Do Thi Thanh
authors.initials: do TT
authors.lastname: Huong
authors.forename: Mark
authors.initials: M
authors.lastname: Bayley
authors.forename: Tobias
authors.initials: T
authors.lastname: Wang
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output; D004524:Eels / Q000502:physiology*; D005260:Female; D006321:Heart / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D018727:Muscarinic Antagonists / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012119:Respiration
chemical_list: D000319:Adrenergic beta-Antagonists; D018727:Muscarinic Antagonists; D001285:Atropine; D011433:Propranolol