title: Low vagally-mediated heart rate variability and increased susceptibility to ventricular arrhythmias in rats bred for high anxiety.
abstract: In humans, there is a documented association between anxiety disorders and cardiovascular disease. Putative underlying mechanisms may include an impairment of the autonomic nervous system control of cardiac function. The primary objective of the present study was to characterize cardiac autonomic modulation and susceptibility to arrhythmias in genetic lines of rats that differ largely in their anxiety level. To reach this goal, electrocardiographic recordings were performed in high-anxiety behavior (HAB, n=10) and low-anxiety behavior (LAB, n=10) rats at rest, during stressful stimuli and under autonomic pharmacological manipulations, and analyzed by means of time- and frequency-domain indexes of heart rate variability. During resting conditions, HAB rats displayed a reduced heart rate variability, mostly in terms of lower parasympathetic (vagal) modulation compared to LAB rats. In HAB rats, this relatively low cardiac vagal control was associated with smaller heart rate responsiveness to acute stressors compared to LAB counterparts. In addition, beta-adrenergic pharmacological stimulation induced a larger incidence of ventricular tachyarrhythmias in HABs compared to LABs. At sacrifice, a moderate increase in heart-body weight ratio was observed in HAB rats. We conclude that high levels of anxiety-related behavior in rats are associated with signs of i) impaired autonomic modulation of heart rate (low vagally-mediated heart rate variability), ii) poor adaptive heart rate responsiveness to stressful stimuli, iii) increased arrhythmia susceptibility, and iv) cardiac hypertrophy. These results highlight the utility of the HAB/LAB model for investigating the mechanistic basis of the comorbidity between anxiety disorders and cardiovascular disease.
authors: Department of Neuroscience, University of Parma, Italy. Electronic address: luca.carnevali@nemo.unipr.it.
authors: Luca
authors: L
authors: Carnevali
authors: Department of Neuroscience, University of Parma, Italy.
authors: Mimosa
authors: M
authors: Trombini
authors: Department of Clinical and Experimental Medicine, University of Parma, Italy.
authors: Gallia
authors: G
authors: Graiani
authors: Department of Clinical and Experimental Medicine, University of Parma, Italy.
authors: Denise
authors: D
authors: Madeddu
authors: Department of Clinical and Experimental Medicine, University of Parma, Italy.
authors: Federico
authors: F
authors: Quaini
authors: Max Planck Institute of Psychiatry, Munich, Germany.
authors: Rainer
authors: R
authors: Landgraf
authors: Department of Behavioural and Molecular Neurobiology, University of Regensburg, Germany.
authors: Inga D
authors: ID
authors: Neumann
authors: School of Biomedical Sciences and Pharmacy, University of Newcastle, New South Wales, Australia.
authors: Eugene
authors: E
authors: Nalivaiko
authors: Department of Neuroscience, University of Parma, Italy.
authors: Andrea
authors: A
authors: Sgoifo
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001007:Anxiety / Q000150:complications* / Q000503:physiopathology; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000503:physiopathology; D001262:Atenolol / Q000494:pharmacology; D004562:Electrocardiography; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D019832:N-Methylscopolamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains / Q000502:physiology; D017208:Rats, Wistar; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology; D055536:Vagus Nerve Stimulation
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D000318:Adrenergic beta-Agonists; D018727:Muscarinic Antagonists; D001262:Atenolol; D007545:Isoproterenol; D019832:N-Methylscopolamine
keywords: Anxiety; Arrhythmias; Autonomic nervous system; Cardiac structure; Heart rate variability