What question did this study set out to answer?

To determine the functional significance of the sarcoplasmic reticulum in supporting high heart rates and elevated blood pressures across four reptile species.

May 1, 2006Journal of Experimental Biology

The role of the sarcoplasmic reticulum in the generation of high heart rates and blood pressures in reptiles

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Population

Ventricular and atrial tissue from four species of reptile: the turtle, the python, the tegu lizard, and the…

Comparison

Force-frequency trials and imposed pauses with… vs Trials without ryanodine and in the absence of…

Design

Preclinical

Authors

GGGina L. J. GalliManchester Academic Health Science Centre HGH. GesserAarhus University ETEdwin W. TaylorOldham Council

Discussion

Member takes

Implication

Reptilian SR Ca2+ findings warrant no clinical extrapolation; leaves open translation to mammalian cardiac models.

Key Points

To determine the functional significance of the sarcoplasmic reticulum in supporting high heart rates and elevated blood pressures across four reptile species.
Conducted in vitro force-frequency and imposed-pause protocols on isolated atrial and ventricular muscle strips from turtles, pythons, tegu lizards, and varanid lizards.
Measured myocardial twitch force before and after pharmacological inhibition of the sarcoplasmic reticulum with ryanodine, in both the presence and absence of adrenaline.
Ryanodine significantly reduced ventricular twitch force within normal physiological frequencies in active varanid lizards and pythons, and reduced atrial force across all physiological rates in tegu and varanid lizards.
Sedentary turtles and pythons exhibited sarcoplasmic reticulum dependence in atrial tissue only at pacing frequencies exceeding maximal in vivo heart rates.
Adrenaline increased twitch force across all species, completely reversing ryanodine-induced contractile depression in ventricular tissue while rescuing atrial tissue only at lower pacing frequencies.

Structured PICO

Population

Ventricular and atrial tissue from four species of reptile: the turtle (Trachemys scripta), the python (Python regius), the tegu lizard (Tupinanvis merianae), and the varanid lizard (Varanus exanthematicus)

Intervention

Force-frequency trials and imposed pauses with the sarcoplasmic reticulum (SR) inhibitor ryanodine, and in the presence of adrenaline

Comparator

Trials without ryanodine and in the absence of adrenaline

Outcome

Twitch force and force-frequency responsesurrogate

This comparative physiology study demonstrates that the sarcoplasmic reticulum plays a species-, tissue-, and frequency-dependent role in cardiac force development in reptiles.

Cite This Study

Galli et al. (2006) studied this question.

synapsesocial.com/papers/6a90e369cd6c08c0eacae52f https://doi.org/10.1242/jeb.02228

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The role of the sarcoplasmic reticulum in the generation of high heart rates and blood pressures in reptiles

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

The role of the sarcoplasmic reticulum in the generation of high heart rates and blood pressures in reptiles

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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