What makes the heart of Boa constrictor (Squamata: Boidae) beat faster?

Rodrigues, João Fabrício Mota; Braga, Roberta da Rocha; Ferreira, Thaís Helena Alencar; Pinheiro, Estéfanni de Castro; Araújo, Géssica dos Santos; Borges-Nojosa, Diva Maria

doi:10.1590/s1984-46702015000100013

Cited by 2 publications

(1 citation statement)

References 11 publications

(30 reference statements)

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“…They are however much slower than mammals and reflect the approximately 10‐fold lower metabolic rate seen in reptiles 13 28 . The HR of snakes can be affected by a wide range of intrinsic and extrinsic factors, but in general it is increased with elevated body temperature, small body size, external stimuli (such as handling), recent meal ingestion and gravidity 16 24 33–36 . Previous studies involving ECG in snakes have been highly variable in design and have frequently included data from small cohort numbers, or large numbers of species restrained by different physical and chemical methods 18–22 .…”

Section: Discussionmentioning

confidence: 99%

Standardisation of electrocardiographic examination in corn snakes (Pantherophis guttatus)

Lewis

Bouvard²,

Eatwell³

et al. 2020

Veterinary Record

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IntroductionCorn snakes are a very common pet reptile species, yet there is an absence of evidence-based literature standardising collection of ECG or detailing ECG deflection morphology in the normal animal. The authors describe a well-tolerated, reproducible technique and detail the cardiac cycle in terms of lead 2 equivalent waveforms and intervals.Animals29 adult corn snakes.Materials and methodsThis prospective study evaluated, under species-appropriate, standardised conditions, a technique for producing standard six-lead ECG tracings. Lead 2 equivalent cardiac cycles were described in detail and statistically analysed for sex, weight, length, heart rate and mean electrical axis.ResultsHigh-quality tracings demonstrated common ECG characteristics for this species, including no Q, S or SV waves, prolonged PR and RT intervals, rhythmic oscillation of the baseline, short TP segments, and a right displaced mean electrical axis. An influence of sex, weight or length on heart rate and mean electrical axis was not identified.ConclusionsTo the authors’ knowledge, this is the first study to describe a standardised technique for recording ECG in significant numbers of normal corn snakes. Ranges have been provided that may be of diagnostic value or form the basis for future development of reference intervals for this species.

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Section: Discussionmentioning

confidence: 99%

Standardisation of electrocardiographic examination in corn snakes (Pantherophis guttatus)

Lewis

Bouvard²,

Eatwell³

et al. 2020

Veterinary Record

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Ontogenetic scaling of the baroreflex function in the green iguana (Iguana iguana)

Filogonio

Rodrigues

Leite

2022

American Journal of Physiology-Regulatory, Integrative and Comp

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Large body mass (Mb) in vertebrates is associated with longer pulse intervals between heartbeats (PI) and thicker arterial walls. Longer PI increases the time for diastolic pressure decay, possibly resulting in loss of cardiac energy as "oscillatory power", whereas thicker arterial walls may affect the transmission of impulses and sensing of pressure fluctuations thus impairing baroreflex function. We aimed to investigate the effect of growth on the relative cardiac energy loss and baroreflex function. We predicted that i) the relative use of cardiac energy should be preserved with increased time constant for pressure decay (τ = vascular resistance × compliance); ii) if arterial circumferential distensibility does not change, baroreflex function should be unaltered with Mb. To test these hypotheses, we used green iguanas (Iguana iguana) weighing from 0.03 to 1.34 kg (43-fold increment in Mb). PI (P=0.037) and τ (P=0.354) increased with Mb whereas the oscillatory power fraction (P=0.245) was unrelated to it. Thus, the concomitant alterations of τ and PI allowed the conservation of cardiac energy in larger lizards. Larger animals had thicker arterial walls (P=0.0007) and greater relative collagen content (P=0.022). Area compliance scaled positively to Mb (P=0.045), though circumferential distensibility (P=0.155) and elastic modulus (P=0.762) were unaltered. Additionally, baroreflex sensitivity measured by both the pharmacological (P=0.152) and sequence methods (P=0.088), and the baroreflex effectiveness index (P=0.306) were also unrelated to Mb. Therefore, changes in arterial morphology did not affect circumferential distensibility and presumably sensing of pressure fluctuation, and the cardiovagal baroreflex is preserved across different Mb.

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What makes the heart of Boa constrictor (Squamata: Boidae) beat faster?

Cited by 2 publications

References 11 publications

Standardisation of electrocardiographic examination in corn snakes (Pantherophis guttatus)

Standardisation of electrocardiographic examination in corn snakes (Pantherophis guttatus)

Ontogenetic scaling of the baroreflex function in the green iguana (Iguana iguana)

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