Verapamil and zero Ca2+ alter responses of cat muscle to halothane and caffeine

1986 ◽  
Vol 60 (3) ◽  
pp. 935-941 ◽  
Author(s):  
P. A. Deuster ◽  
E. L. Bockman ◽  
H. Biscardi ◽  
S. M. Muldoon
Keyword(s):  
Electrical Stimulation ◽  
Channel Blocker ◽  
Fiber Type ◽  
Ringer Solution ◽  
Fiber Types ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Ca2 Channels ◽  
Caffeine Contractures

Strips of soleus (slow twitch, oxidative) and gracilis (fast-twitch, glycolytic) muscle were obtained from 27 anesthetized cats and mounted in organ baths filled with oxygenated Krebs-Ringer solution (37 degrees C). The responses to caffeine, halothane (1%), caffeine in the presence of halothane, and electrical stimulation in the presence of halothane were examined in the two fiber types. These responses were compared with those observed in paired strips of muscle that had been treated with verapamil (10 or 28 microM), a slow calcium (Ca2+) channel blocker, with zero Ca2+, or with zero Ca2+ where magnesium (3.7 mM Ca2+) was added to replace the Ca2+. Halothane-induced contractures in the soleus were blocked by verapamil and zero Ca2+. Caffeine-induced contractures and tetanic contractions were attenuated in zero Ca2+ and by verapamil in both fiber types. Halothane overcame verapamil-induced reductions of caffeine contractures and tetanic contractions in both fiber types. In contrast, halothane did not overcome zero Ca2+-induced reductions in caffeine contractures or tetanic contractions in either fiber type. Furthermore, the addition of Mg2+ to the zero Ca2+ did not restore the responses. The findings with verapamil indicate that in cat muscle, both halothane- and caffeine-induced contractures and tetanic contractions are dependent on the influx of extracellular Ca2+. This extracellular Ca2+ may enter through the slow Ca2+ channels. However, because halothane in combination with caffeine or electrical stimulation overcame the effects of verapamil, there may be other sites involved.

scholarly journals lncRNA-Six1 Is a Target of miR-1611 that Functions as a ceRNA to Regulate Six1 Protein Expression and Fiber Type Switching in Chicken Myogenesis

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 243 ◽  
Author(s):  
Manting Ma ◽  
Bolin Cai ◽  
Liang Jiang ◽  
Bahareldin Ali Abdalla ◽  
Zhenhui Li ◽  
...  
Keyword(s):  
Fiber Type ◽  
Muscle Fibers ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Proliferation And Differentiation ◽  
Slow Twitch Muscle ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Emerging studies indicate important roles for non-coding RNAs (ncRNAs) as essential regulators in myogenesis, but relatively less is known about their function. In our previous study, we found that lncRNA-Six1 can regulate Six1 in cis to participate in myogenesis. Here, we studied a microRNA (miRNA) that is specifically expressed in chickens (miR-1611). Interestingly, miR-1611 was found to contain potential binding sites for both lncRNA-Six1 and Six1, and it can interact with lncRNA-Six1 to regulate Six1 expression. Overexpression of miR-1611 represses the proliferation and differentiation of myoblasts. Moreover, miR-1611 is highly expressed in slow-twitch fibers, and it drives the transformation of fast-twitch muscle fibers to slow-twitch muscle fibers. Together, these data demonstrate that miR-1611 can mediate the regulation of Six1 by lncRNA-Six1, thereby affecting proliferation and differentiation of myoblasts and transformation of muscle fiber types.

scholarly journals Comparative analysis of the transcriptomes of EDL, psoas, and soleus muscles from mice

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Pabodha Hettige ◽  
Uzma Tahir ◽  
Kiisa C. Nishikawa ◽  
Matthew J. Gage
Keyword(s):  
Skeletal Muscles ◽  
Striated Muscle ◽  
Fiber Type ◽  
Expression Patterns ◽  
Fiber Types ◽  
Muscle Adaptation ◽  
Myosin Heavy Chain Isoform ◽  
Genes Encoding ◽  
Slow Twitch ◽  
Fast Twitch

Abstract Background Individual skeletal muscles have evolved to perform specific tasks based on their molecular composition. In general, muscle fibers are characterized as either fast-twitch or slow-twitch based on their myosin heavy chain isoform profiles. This approach made sense in the early days of muscle studies when SDS-PAGE was the primary tool for mapping fiber type. However, Next Generation Sequencing tools permit analysis of the entire muscle transcriptome in a single sample, which allows for more precise characterization of differences among fiber types, including distinguishing between different isoforms of specific proteins. We demonstrate the power of this approach by comparing the differential gene expression patterns of extensor digitorum longus (EDL), psoas, and soleus from mice using high throughput RNA sequencing. Results EDL and psoas are typically classified as fast-twitch muscles based on their myosin expression pattern, while soleus is considered a slow-twitch muscle. The majority of the transcriptomic variability aligns with the fast-twitch and slow-twitch characterization. However, psoas and EDL exhibit unique expression patterns associated with the genes coding for extracellular matrix, myofibril, transcription, translation, striated muscle adaptation, mitochondrion distribution, and metabolism. Furthermore, significant expression differences between psoas and EDL were observed in genes coding for myosin light chain, troponin, tropomyosin isoforms, and several genes encoding the constituents of the Z-disk. Conclusions The observations highlight the intricate molecular nature of skeletal muscles and demonstrate the importance of utilizing transcriptomic information as a tool for skeletal muscle characterization.

scholarly journals Activity-dependent nuclear translocation and intranuclear distribution of NFATc in adult skeletal muscle fibers

2001 ◽  
Vol 155 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Yewei Liu ◽  
Zoltán Cseresnyés ◽  
William R. Randall ◽  
Martin F. Schneider
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Nuclear Translocation ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Adult Skeletal Muscle ◽  
Skeletal Muscle Fibers ◽  
Slow Twitch ◽  
Nuclear Foci ◽  
Fast Twitch

TTranscription factor nuclear factor of activated T cells NFATc (NFATc1, NFAT2) may contribute to slow-twitch skeletal muscle fiber type–specific gene expression. Green fluorescence protein (GFP) or FLAG fusion proteins of either wild-type or constitutively active mutant NFATc [NFATc(S→A)] were expressed in cultured adult mouse skeletal muscle fibers from flexor digitorum brevis (predominantly fast-twitch). Unstimulated fibers expressing NFATc(S→A) exhibited a distinct intranuclear pattern of NFATc foci. In unstimulated fibers expressing NFATc–GFP, fluorescence was localized at the sarcomeric z-lines and absent from nuclei. Electrical stimulation using activity patterns typical of slow-twitch muscle, either continuously at 10 Hz or in 5-s trains at 10 Hz every 50 s, caused cyclosporin A–sensitive appearance of fluorescent foci of NFATc–GFP in all nuclei. Fluorescence of nuclear foci increased during the first hour of stimulation and then remained constant during a second hour of stimulation. Kinase inhibitors and ionomycin caused appearance of nuclear foci of NFATc–GFP without electrical stimulation. Nuclear translocation of NFATc–GFP did not occur with either continuous 1 Hz stimulation or with the fast-twitch fiber activity pattern of 0.1-s trains at 50 Hz every 50 s. The stimulation pattern–dependent nuclear translocation of NFATc demonstrated here could thus contribute to fast-twitch to slow-twitch fiber type transformation.

Enhanced technique to measure proteins in single segments of human skeletal muscle fibers: fiber-type dependence of AMPK-α1 and -β1

2011 ◽  
Vol 110 (3) ◽  
pp. 820-825 ◽  
Author(s):  
Robyn M. Murphy
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Significant Advance ◽  
Vastus Lateralis Muscle ◽  
Fiber Types ◽  
Freeze Dried ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Muscle Biopsies

Human physiological studies typically use skeletal muscle biopsies from the heterogeneous vastus lateralis muscle comprised of both fast-twitch and slow-twitch fiber types. It is likely that potential changes of physiological importance are overlooked because fiber-type specific responses may not be apparent in the whole muscle preparation. A technological advance in Western blotting is presented where proteins are analyzed in just one small segment (<2 mm) of individual fibers dissected from freeze-dried muscle samples using standard laboratory equipment. A significant advance is being able to classify every fiber at the level of both contractile (myosin heavy chain and tropomyosin) and sarcoplasmic reticulum [sarco(endo)plasmic reticulum Ca2+-ATPase type 1] properties and then being able to measure specific proteins in the very same segments. This removes the need to fiber type segments before further analyses and, as such, dramatically reduces the time required for sample collection. Compared with slow-twitch fibers, there was less AMP-activated protein kinase (AMPK)-α1 (∼25%) and AMPK-β1 (∼60%) in fast-twitch fibers from human skeletal muscle biopsies.

scholarly journals Skeletal muscle and fiber type-specific intramyocellular lipid accumulation in obese mice

2021 ◽  
Author(s):  
Nejc Umek ◽  
Simon Horvat ◽  
Erika Cvetko
Keyword(s):  
Muscle Fiber ◽  
Lipid Accumulation ◽  
High Fat Diet ◽  
Fiber Type ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Intramyocellular Lipid ◽  
Obese Mice ◽  
Slow Twitch ◽  
Fast Twitch

In obesity, accumulation of lipid droplets in skeletal muscle fibers and a shift towards fast muscle fiber types can both contribute to insulin resistance. However, it is not yet clear how intramyocellular lipid accumulation and fiber type changes are associated. Therefore, we investigated to what extent the lipids accumulated in a fiber type-specific manner in the functionally similar fast-, intermediate- and slow‑twitch gastrocnemius, plantaris, and soleus muscles, respectively, in high-fat diet-induced obese 54-week-old female C57BL/6JOlaHsd mice (n=9) compared to control standard-diet-treated lean mice (n=9). A high-fat diet was administered for 26 weeks. Fiber-type specific intramyocellular lipid content analysis and muscle fiber typing were performed using histochemical analysis of lipids with Sudan Black and immunohistochemical analysis of myosin heavy chains on serial sections of skeletal muscles. Compared to the lean mice, the lipid accumulation was most prominent in types 2a and 2x/d fibers (p<0.05) of fast-twitch gastrocnemius and intermediate plantaris muscles in the obese mice, while in slow-twitch soleus muscle, there was no significant lipid accumulation in the obese animals. Furthermore, the slow-twitch soleus muscle of the obese mice with no significant change in muscle fiber diameters exhibited the most pronounced shift towards fast-type myosin heavy chain isoform expression (p<0.05). In contrast, the fast-twitch and intermediate-twitch gastrocnemius and plantaris muscles, respectively, in which the muscle fiber diameters increased (p<0.05), were more resistant toward myosin heavy chain expression changes. In conclusion, we demonstrated both muscle- and fiber-type specificity in intramyocellular lipid accumulation in obese mice, suggesting that in obesity, similar muscle fiber types in different muscles accumulate lipids differentially.

Slow to fast alterations in skeletal muscle fibers caused by clenbuterol, a beta 2-receptor agonist

1988 ◽  
Vol 254 (6) ◽  
pp. E726-E732 ◽  
Author(s):  
R. J. Zeman ◽  
R. Ludemann ◽  
T. G. Easton ◽  
J. D. Etlinger
Keyword(s):  
Muscle Fiber ◽  
Receptor Agonist ◽  
Fiber Type ◽  
Fiber Types ◽  
Cross Sectional ◽  
Type Composition ◽  
Slow Twitch ◽  
Beta 2 ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Chronic treatment of rats with clenbuterol, a beta 2-receptor agonist (8–12 wk), caused hypertrophy of histochemically identified fast- but not slow-twitch fibers within the soleus, while the mean areas of both fiber types were increased in the extensor digitorum longus (EDL). In contrast, treatment with the beta 2-receptor antagonist, butoxamine, reduced fast-twitch fiber size in both muscles. In the solei and to a lesser extent in the EDLs, the ratio of the number of fast- to slow-twitch fibers was increased by clenbuterol, while the opposite was observed with butoxamine. The muscle fiber hypertrophy observed in the EDL was accompanied by parallel increases in maximal tetanic tension and muscle cross-sectional area, while in the solei, progressive increases in rates of force development and relaxation toward values typical of fast-twitch muscles were also observed. Our results suggest a role of beta 2-receptors in regulating muscle fiber type composition as well as growth.

Relative independence of metabolic enzymes and neuromuscular activity

1984 ◽  
Vol 56 (6) ◽  
pp. 1602-1607 ◽  
Author(s):  
K. M. Baldwin ◽  
R. R. Roy ◽  
R. D. Sacks ◽  
C. Blanco ◽  
V. R. Edgerton
Keyword(s):  
Citrate Synthase ◽  
Fiber Type ◽  
Medial Gastrocnemius ◽  
Fatigue Properties ◽  
Fiber Types ◽  
Oxidative Potential ◽  
Relative Independence ◽  
Slow Twitch Muscle ◽  
Slow Twitch ◽  
Fast Twitch

Effects of spinal cord transection in 2-wk-old cats on the metabolic, histochemical, and fatigue properties of a fast- and a slow-twitch muscle were determined. Chronic (6–12 mo) spinalization (Sp) resulted in an increased ratio of fast-twitch, oxidative-glycolytic (FOG) to slow-twitch, oxidative (SO) fibers in soleus (SOL). In medial gastrocnemius (MG), Sp produced a histochemical profile suggesting that fast fibers were increased at the expense of slow fibers. Changes in biochemical markers for oxidative (citrate synthase) and glycolytic (GPD) potential were consistent with the histochemical findings. The fatigue index of Sp MG and SOL remained normal and was consistent with the type and degree of fiber type change. Daily treadmill exercise did not markedly alter any of the adaptations. The metabolic and fatigue properties of skeletal muscle of Sp cats are consistent with the view that as some fibers develop “faster-like” characteristics, the oxidative and the glycolytic potential is also enhanced. As was true of the contractile properties and related biochemical data, the changes observed suggest that significant changes occurred within as well as across fiber types. These data, in conjunction with that of chronic EMG recordings, provide evidence that there is a relative independence of both the oxidative potential and the fatigability of a muscle relative to its quantity of activation.

Effect of thin filament length on the force-sarcomere length relation of skeletal muscle

1991 ◽  
Vol 260 (5) ◽  
pp. C1060-C1070 ◽  
Author(s):  
H. L. Granzier ◽  
H. A. Akster ◽  
H. E. Ter Keurs
Keyword(s):  
Thin Filament ◽  
Sarcomere Length ◽  
Fiber Type ◽  
Thick Filament ◽  
Fiber Types ◽  
Single Region ◽  
Slow Twitch ◽  
The Difference ◽  
Slow Twitch Fibers ◽  
Fast Twitch

We studied a slow- and a fast-twitch muscle fiber type of the perch that have different thin filament lengths. The force-sarcomere length relations were measured, and it was tested whether their descending limbs were predicted by the cross-bridge theory. To determine the predicted relations, filament lengths were measured by electron microscopy. Measurements were corrected for shrinkage with the use of I-band and H-zone periodicities. Thick filament lengths of the two fiber types were found to be similar (1.63 +/- 0.06 and 1.64 +/- 0.10 microns for slow- and fast-twitch fibers, respectively), whereas the thin filament lengths were clearly different: 1.24 +/- 0.10 microns (n = 86) for the slow-twitch type and 0.94 +/- 0.04 microns (n = 94) for the fast type. The descending limbs of the two fiber types are therefore predicted to be shifted along the sarcomere length axis by approximately 0.6 microns. Sarcomere length was measured on-line by laser diffraction in a single region in the center of the fibers. The passive force-sarcomere strain relation increased much more steeply in the slow-twitch fibers. The descending limb of the active force-sarcomere length relation of fast twitch fibers was linear (r = 0.92), but was found at sarcomere lengths approximately 0.1 micron greater than predicted. The descending limb of the slow-twitch fibers was also linear (r = 0.87) but was now found at sarcomere lengths approximately 0.05 microns less than predicted. The difference in position of the descending limbs of the two fiber types amounted to 0.5 microns, approximately 0.1 micron less than predicted. The difference between measured and predicted descending limbs was statistically insignificant.

Influence of fiber-type composition on recovery from tourniquet-induced skeletal muscle ischemia–reperfusion injury

2008 ◽  
Vol 33 (2) ◽  
pp. 272-281 ◽  
Author(s):  
Thomas J. Walters ◽  
John F. Kragh ◽  
David G. Baer
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Contractile Function ◽  
Fiber Type ◽  
Ischemia Reperfusion ◽  
Fiber Types ◽  
Fiber Type Composition ◽  
Type Composition ◽  
Slow Twitch ◽  
Fast Twitch

This study was designed to determine if previously reported differences in the functional impairment of muscles composed of predominantly different fiber types occurs following extended periods of ischemia. We hypothesized that the soleus (Sol) muscle, a predominantly slow-twitch muscle, would be less vulnerable to tourniquet-induced ischemia–reperfusion than the plantaris (Plant), a predominantly fast-twitch muscle, as determined by the assessment of isometric contractile function. Male Sprague–Dawley rats were assigned to one of the following groups to undergo tourniquet application (TKA) (n = 6/group): 2 h TKA, 2 d recovery; 4 h TKA, 2 d recovery; 2 h TKA, 14 d recovery; or 4 h TKA, 14 d recovery. In situ isometric contractile properties were assessed in the predominantly slow-twitch Sol and the predominantly fast-twitch Plant; the contralateral muscle served as the internal control. At 2 d, muscle contraction could not be elicited via neural stimulation, but muscles did contract with direct stimulation, which indicates neural injury. This condition was resolved by day 14. At this time point, tetanic tension (Po) in the Plant was reduced by 45% and 69% in the 2 and 4 h groups, respectively. Po for the Sol was unaffected in the 2 h group, but was reduced by 30% in the 4 h group. The fatigue resistance of the Plant was increased 2 fold in the 4 h group and was unchanged in all other groups. These results demonstrate that vulnerability to tourniquet-induced ischemia–reperfusion injury is dramatically different with respect to muscle fiber-type composition.

Blood flow to different skeletal muscle fiber types during contraction

1983 ◽  
Vol 245 (2) ◽  
pp. H265-H275 ◽  
Author(s):  
B. G. Mackie ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Blood Flows ◽  
Fast Twitch

Blood flow to fast-twitch red (FTR), fast-twitch white (FTW), and slow-twitch red (STR) muscle fiber sections of the gastrocnemius-plantaris-soleus muscle group was determined using 15 +/- 3-microns microspheres during in situ stimulation in pentobarbital-anesthetized rats. Steady-state blood flows were assessed during the 10th min of contraction using twitch (0.1, 0.5, 1, 3, and 5 Hz) and tetanic (7.5, 15, 30, 60, and 120/min) stimulation conditions. In addition, an earlier blood flow determination was begun at 3 min (twitch series) or at 30 s (tetanic series) of stimulation. Blood flow was highest in the FTR (220-240 ml X min-1 X 100 g-1), intermediate in the STR (140), and lowest in the FTW (70-80) section during tetanic contraction conditions estimated to coincide with the peak aerobic function of each fiber type. These blood flows are fairly proportional to the differences in oxidative capacity among fiber types. Further, their absolute values are similar to those predicted from the relationship between blood flow and oxidative capacity found by others for dog and cat muscles. During low-frequency contraction conditions, initial blood flow to the FTR and STR sections were excessively high and not dependent on contraction frequency. However, blood flows subsequently decreased to values in keeping with the relative energy demands. In contrast, FTW muscle did not exhibit this time-dependent relative hyperemia. Thus, besides the obvious quantitative differences between skeletal muscle fiber types, there are qualitative differences in blood flow response during contractions. Our findings establish that, based on fiber type composition, a heterogeneity in blood flow distribution can occur within a whole muscle during contraction.

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