Respiratory sinus arrhythmia is a major component of heart rate variability in undisturbed, remotely monitored rattlesnakes, Crotalus durissus

Author(s)

Sanches, Pollyana V. W. ^{[1, 2]} ; Taylor, Edwin W. ^{[1, 3]} ; Duran, Livia M. ^{[1, 2]} ; Cruz, Andre L. ^{[2, 4]} ; Dias, Daniel P. M. ^[5] ; Leite, Cleo A. C. ^{[1, 2]}

Affiliation

^[1] Fed Univ Sao Carlos UFSCar, Dept Physiol Sci, BR-13565905 Sao Carlos, SP - Brazil

^[2] CNPq, FISC, FAPESP, INCT, Natl Inst Sci & Technol Comparat Physiol, BR-13506900 Rio Claro, SP - Brazil

^[3] Univ Birmingham, Sch Biosci, Birmingham B15 2TT, W Midlands - England

^[4] Fed Univ Bahia UFBA, Inst Biol, BR-40140310 Salvador, BA - Brazil

^[5] Barao de Maua Univ Ctr, BR-14090180 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Journal of Experimental Biology; v. 222, n. 9 MAY 2019.
• Web of Science Citations: 1

Abstract

ECG recordings were obtained using an implanted telemetry device from the South American rattlesnake, Crotalus durissus, held under stable conditions without restraining cables or interaction with researchers. Mean heart rate (f(H)) recovered rapidly (<24 h) from anaesthesia and operative procedures. This preceded a more gradual development of heart rate variability (HRV), with instantaneous f(H) increasing during each lung ventilation cycle. Atropine injection increased mean f(H) and abolished HRV. Complete autonomic blockade revealed a cholinergic tonus on the heart of 55% and an adrenergic tonus of 37%. Power spectral analysis of HRV identified a peak at the same frequency as ventilation. This correlation was sustained after temperature changes and it was more evident, marked by a more prominent power spectrum peak, when ventilation is less episodic. This HRV component is homologous to that observed in mammals, termed respiratory sinus arrhythmia (RSA). Evidence for instantaneous control of f(H) indicated rapid conduction of activity in the cardiac efferent nervous supply, as supported by the description of myelinated fibres in the cardiac vagus. Establishment of HRV 10 days after surgical intervention seems a reliable indicator of the re-establishment of control of integrative functions by the autonomic nervous system. We suggest that this criterion could be applied to other animals exposed to natural or imposed trauma, thus improving protocols involving animal handling, including veterinarian procedures. (AU)

• FAPESP's process: 08/57712-4 - The National Institute of Comparative Physiological Research
• Grantee: Augusto Shinya Abe
• Support Opportunities: Research Projects - Thematic Grants