Impacts of prolonged chlorpyrifos exposure on locomotion and slow-and fast- twitch skeletal muscles contractility in rats

Hallal, Nancy; Sabbouri, Hiba El Khayat El; Salami, Ali; Ramadan, Wiâm; Khachfe, Hassan; Moustafa, Mohamed E.; Khalil, Mahmoud; Joumaa, Wissam H.

doi:10.1016/j.toxrep.2019.06.006

Cited by 9 publications

(7 citation statements)

References 52 publications

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“…During twitch experiments, while the activation times of both EDL and SOL muscle were comparable to those reported in previous studies, the relaxation times for SOL muscle were significantly longer than previously reported (Hallal et al., 2019; Segal et al., 1986). When searching for L o by stretching the muscle, we noticed that the twitch relaxation time was noticeably prolonged at longer muscle lengths in SOL muscle while the twitch relaxation time appeared less sensitive to muscle length in EDL muscle.…”

Section: Discussionsupporting

confidence: 86%

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Thick filament activation is different in fast‐ and slow‐twitch skeletal muscle

Gong

Regnier

et al. 2022

The Journal of Physiology

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The contractile properties of fast‐twitch and slow‐twitch skeletal muscles are primarily determined by the myosin isoform content and modulated by a variety of sarcomere proteins. X‐ray diffraction studies of regulatory mechanisms in muscle contraction have focused predominately on fast‐ or mixed‐fibre muscle with slow muscle being much less studied. Here, we used time‐resolved X‐ray diffraction to investigate the dynamic behaviour of the myofilament proteins in relatively pure slow‐twitch‐fibre rat soleus (SOL) and pure fast‐twitch‐fibre rat extensor digitorum longus (EDL) muscle during twitch and tetanic contractions at optimal length. During twitch contractions the diffraction signatures indicating a transition in the myosin heads from ordered OFF states, where heads are held close to the thick filament backbone, to disordered ON states, where heads are free to bind to thin filaments, were found in EDL and not in SOL muscle. During tetanic contraction, changes in the disposition of myosin heads as active tension develops is a quasi‐stepwise process in EDL muscle whereas in SOL muscle this relationship appears to be linear. The observed reduced extensibility of the thick filaments in SOL muscle as compared to EDL muscles indicates a molecular basis for this behaviour. These data indicate that for the EDL, thick filament activation is a cooperative strain‐induced mechano‐sensing mechanism, whereas for the SOL, thick filament activation has a more graded response. These different approaches to thick filament regulation in fast‐ and slow‐twitch muscles may be adaptations for short‐duration, strong contractions versus sustained, finely controlled contractions, respectively. Key points Fast‐twitch muscle and slow‐twitch muscle are optimized for strong, short‐duration contractions and for tonic postural activity, respectively. Structural events (OFF to ON transitions) in the myosin‐containing thick filaments in fast muscle help determine the timing and strength of contractions, but these have not been studied in slow‐twitch muscle. The X‐ray diffraction signatures of structural OFF to ON transitions are different in fast extensor digitorum longus (EDL) and slow soleus (SOL) muscle, being completely absent during twitches in soleus muscle and blunted during tetanic contractions SOL as compared to EDL Quasi‐stepwise thick filament structural OFF to ON transitions in fast twitch muscle may be an adaptation for rapid, ballistic movements, whereas more graded OFF to ON structural transitions in slow‐twitch muscle may be an adaptation for slower, finer motions.

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Section: Discussionsupporting

confidence: 86%

“…The average plateau tension of EDL and SOL muscle during tetanic contraction reported in this study is ∼90 mN/mm 2 . Previous studies reported the tetanic tension of EDL and SOL muscle range from ∼30 mN/mm 2 (Hallal et al., 2019) to ∼170 mN/mm 2 (Segal et al., 1986; Spector, 1985). The reasons for these discrepancies are unclear.…”

Section: Discussionmentioning

confidence: 95%

Thick filament activation is different in fast‐ and slow‐twitch skeletal muscle

Gong

Regnier

et al. 2022

The Journal of Physiology

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Section: Resultssupporting

confidence: 92%

“…After tension peaked, it decayed with a half-time of 659.4 ms (95% CI: 502.8 ms to 815.9 ms). The twitch tensions for both muscles reported here are comparable with those reported previously (Hallal et al, 2019). The hexagonal crystal lattice formed by the myosin-containing thick and actin-containing thin filaments in the sarcomere give rise to the two strongest equatorial reflections, the 1,0 and the 1,1.…”

Section: Structural Change During Fixed-end Twitch Contractionssupporting

confidence: 89%

Thick Filament Activation Is Different in Fast and Slow-Twitch Skeletal Muscle

Gong

Regnier

et al. 2022

Preprint

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The contractile properties of fast-twitch and slow-twitch skeletal muscles are primarily determined by the myosin isoform content and modulated by a variety of sarcomere proteins. X-ray diffraction studies of regulatory mechanisms in muscle contraction have focused predominately on fast- or mixed-fiber muscle with slow muscle being much less studied. Here, we used time-resolved x-ray diffraction to investigate the dynamic behavior of the myofilament proteins in relatively pure slow fiber rat soleus (SOL) and pure fast fiber rat extensor digitorum longus (EDL) muscle during twitch and tetanic contractions at optimal length. During twitch contractions the diffraction signatures indicating a transition in the myosin heads from ordered OFF states, where heads are held close to the thick filament backbone, to disordered ON states, where heads are free to bind to thin filaments, were found in EDL and not in SOL muscle. During tetanic contraction, changes in the disposition of myosin heads as active tension develops is a cooperative process in EDL muscle whereas in SOL muscle this relationship is less cooperative. The observed reduced extensibility of the thick filaments in SOL muscle as compared to EDL muscles indicate a molecular basis for this behavior. These data indicate that for the EDL thick filament activation is a cooperative strain-induced mechano-sensing mechanism, whereas for the SOL thick filament activation has a more graded response. These different approaches to thick filament regulation in fast- and slow-twitch muscles may be adaptations for short duration, strong contractions versus sustained, finely controlled contractions, respectively.

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“…☆The data article is related to the research article titled“Impacts of prolonged chlorpyrifos exposure on locomotion and slow-and fast-twitch skeletal muscles contractility in rats” [1]. …”

mentioning

confidence: 99%

Data on dysfunctional muscle contraction and genes contractile expression associated with chlorpyrifos exposure in slow twitch skeletal muscle

et al. 2019

Self Cite

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Chlorpyrifos (CPF) is a toxic organophosphate commonly used worldwide. Its residues are being detected in different environmental matrixes and hence in the food chain. Repeated CPF exposure might pose health risk for the general population on long term. This data article contains the data of contractility impairment further to dietary exposure to CPF on a hind limb skeletal muscle; soleus, a typical slow twitch skeletal muscle. Thirty adult male rats Sprague Dawley are divided into three groups receiving the following daily diet for 6 weeks: Group 1 (vehicle), Group 2: CPF1 (CPF 1mg/kg/day) and Group 3: CPF5 (CPF 5 mg/kg/day). Soleus twitch tension and fatigability index are determined at the end of the treatment. The activity of acteylcholinesterase enzyme is assessed in the tissues homogenate. Additionally, we examined the expression levels of ryanodine type 1 receptor (RyR1), ATPase Sarcoplasmic/Endoplasmic Reticulum Ca2+ Transporting 1 (Atp2a1), ATPase Sarcoplasmic/Endoplasmic Reticulum Ca2+ Transporting 2 (Atp2a2) and nicotinic acetylcholine receptor (nAChR) in CPF-exposed skeletal muscle tissue using quantitative real time polymerase chain reaction.CPF exposure at two different doses induced an increase in twitch contraction in soleus muscle along with an increase in fatigability index. These increases are accompanied by low level of acetylcholinesterase enzyme activity as well as modification in genes level expression of nAChR, RyR1, Atp2a1 and Atp2a2 involved in contractility.

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Impacts of prolonged chlorpyrifos exposure on locomotion and slow-and fast- twitch skeletal muscles contractility in rats

Cited by 9 publications

References 52 publications

Thick filament activation is different in fast‐ and slow‐twitch skeletal muscle

Thick filament activation is different in fast‐ and slow‐twitch skeletal muscle

Thick Filament Activation Is Different in Fast and Slow-Twitch Skeletal Muscle

Data on dysfunctional muscle contraction and genes contractile expression associated with chlorpyrifos exposure in slow twitch skeletal muscle

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