Effect of changes in temperature on the force–frequency relationship in the heart of catfish (Clarias gariepinus)

El-Sayed, Mohamed F.; Abu-Amra, El-Sabry; Badr, Amr

doi:10.1016/j.jobaz.2012.07.010

Cited by 6 publications

(4 citation statements)

References 45 publications

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“…The temperature changed the force–frequency response in caiman hearts. It has been reported that changes in temperature induce alterations of the main sources of Ca 2+ to initiate contraction (El‐Sayed et al, 2012). In most fish, acute increases in temperature induce a marked reduction FFR, despite the fact that thermal transitions occur in their natural habitat (Costa et al, 2000; Rantin et al, 2020; Shiels & Farrell, 1997).…”

Section: Discussionmentioning

confidence: 99%

Effects of change in temperature on the cardiac contractility of broad‐snouted caiman (Caiman latirostris) during digestion

2021

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In many reptiles, digestion has been associated with the selection of higher body temperatures, the so‐called post‐prandial thermophilic response. This study aimed to investigate the excitation–contraction (E–C) coupling in postprandial broad‐snouted caimans (Caiman latirostris) in response to acute warming within a preferred body temperature range of crocodiles. Isometric preparations subjected to a temperature transition from 25°C to 30°C were used to investigate myocardial contractility of postprandial caimans, that is, 48 h after the animals ingested a rodent meal corresponding to 15% of body mass. The caiman heart exhibits a negative force–frequency relationship that is independent of the temperature. At 25°C, cardiac muscle was able to maintain a constant force up to 36 bpm, above which it decreased significantly, reaching minimum values at the highest frequency of 84 bpm. Moreover, E–C coupling is predominantly dependent on transsarcolemmal Ca2+ transport denoted by the lack of significant ryanodine effects on force generation. On the contrary, ventricular strips at 30°C were able to sustain the cardiac contractility at higher pacing frequencies (from 12 to 144 bpm) due to an important role of Na+/Ca2+ exchanger in Ca2+ cycling, as indicated by the decay of the post‐rest contraction, and a significant contribution of the sarcoplasmic reticulum above 72 bpm. Our results demonstrated that the myocardium of postprandial caimans exhibits a significant degree of thermal plasticity of E–C coupling during acute warming. Therefore, myocardial contractility can be maximized when postprandial broad‐snouted caimans select higher body temperatures (preferred temperature zone) following feeding.

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Section: Discussionmentioning

confidence: 99%

Effects of change in temperature on the cardiac contractility of broad‐snouted caiman (Caiman latirostris) during digestion

2021

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“…The recording of the twitch force developed by the ventricular strips was used as El-Sayed et al (2012).…”

Section: Ventricular Strip Preparationmentioning

confidence: 99%

“…However, the SR can play an important role during cardiac E-C coupling in some fishes (Landeira-Fernandez et al, 2004;Castilho et al, 2007;El-Sayed et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of cardiac sarcoplasmic reticulum and sarcolemma in the ventricle of catfish (Clarias gariepinus)

Abu-Amra

El-Sayed

Badr

2015

The Journal of Basic & Applied Zoology

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The present study was undertaken to examine the relative contribution of the SR-Ca 2+ release and sarcolemmal Ca 2+ channels in developing the cardiac force at two different temperatures (20 and 30°C) in the catfish (Clarias gariepinus).The sarcolemmal Ca 2+ contribution of activator Ca 2+ was greater at a test temperature of 30°C as assessed by verapamil. Whereas the SR-Ca 2+ contribution was higher at 20 and 30°C and a frequency rate of 0.2 and 0.4 Hz as assessed by caffeine and adrenaline, respectively. Bradykinin potentiating factor (BPF 7 ) which was isolated from jelly fish (Cassiopea andromeda) decreased the cardiac force developed at a frequency rate of 0.2 Hz and a temperature of 20°C, whereas it increased the force developed at frequency rates of 0.2 and 0.4 Hz at 30°C. These results indicate that BPF 7 may act like verapamil in reducing the cardiac force through blocking the sarcolemmal Ca 2+ channels at low temperature and like adrenaline in an increase of the cardiac force developed at warm temperature and the high frequency rate through stimulation of SR-Ca 2+ activator. Therefore, this study indicates that the sarcolemmal Ca 2+ influx and the SR-Ca 2+ release contributors of activator Ca 2+ for cardiac force development in the catfish heart were significantly greater at warm temperature and at the pacing frequency rates of 0.2 and 0.4 Hz as assessed by verapamil, adrenaline, caffeine and BPF 7 . However, the relative contribution of the sarcolemmal Ca 2+ influx in the development of cardiac force in the catfish heart was greater than that of SR-Ca 2+ release. ª 2015 The Egyptian German Society for Zoology. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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“…In mammals, such as humans, rabbits, and guinea pigs, the relationship between cardiac contractile force and stimulation frequency (FFR) has been recorded to have a positive slope under physiological rates, which is known as the Bowditch phenomena, and a negative slope at higher frequencies [ 3 , 5 , 6 , 7 , 8 ]. The FFR is found to be negative in small animals, such as rats, mice, turtles, lizards, snakes, and fish [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. The negative FFR in humans is suggested to show an adaptation of the heart in rapid pacing [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

The Role of Ca2+ Sparks in Force Frequency Relationships in Guinea Pig Ventricular Myocytes

2022

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Calcium sparks are the elementary Ca2+ release events in excitation-contraction coupling that underlie the Ca2+ transient. The frequency-dependent contractile force generated by cardiac myocytes depends upon the characteristics of the Ca2+ transients. A stochastic computational local control model of a guinea pig ventricular cardiomyocyte was developed, to gain insight into mechanisms of force-frequency relationship (FFR). This required the creation of a new three-state RyR2 model that reproduced the adaptive behavior of RyR2, in which the RyR2 channels transition into a different state when exposed to prolonged elevated subspace [Ca2+]. The model simulations agree with previous experimental and modeling studies on interval-force relations. Unlike previous common pool models, this local control model displayed stable action potential trains at 7 Hz. The duration and the amplitude of the [Ca2+]myo transients increase in pacing rates consistent with the experiments. The [Ca2+]myo transient reaches its peak value at 4 Hz and decreases afterward, consistent with experimental force-frequency curves. The model predicts, in agreement with previous modeling studies of Jafri and co-workers, diastolic sarcoplasmic reticulum, [Ca2+]sr, and RyR2 adaptation increase with the increased stimulation frequency, producing rising, rather than falling, amplitude of the myoplasmic [Ca2+] transients. However, the local control model also suggests that the reduction of the L-type Ca2+ current, with an increase in pacing frequency due to Ca2+-dependent inactivation, also plays a role in the negative slope of the FFR. In the simulations, the peak Ca2+ transient in the FFR correlated with the highest numbers of SR Ca2+ sparks: the larger average amplitudes of those sparks, and the longer duration of the Ca2+ sparks.

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Effect of changes in temperature on the force–frequency relationship in the heart of catfish (Clarias gariepinus)

Cited by 6 publications

References 45 publications

Effects of change in temperature on the cardiac contractility of broad‐snouted caiman (Caiman latirostris) during digestion

Effects of change in temperature on the cardiac contractility of broad‐snouted caiman (Caiman latirostris) during digestion

Temperature dependence of cardiac sarcoplasmic reticulum and sarcolemma in the ventricle of catfish (Clarias gariepinus)

The Role of Ca2+ Sparks in Force Frequency Relationships in Guinea Pig Ventricular Myocytes

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