scholarly journals Chronic low-frequency stimulation of rabbit fast-twitch muscle induces partial inactivation of the sarcoplasmic reticulum Ca2+-ATPase and changes in its tryptic cleavage

1990 ◽  
Vol 192 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Laszlo DUX ◽  
Howard J. GREEN ◽  
Dirk PETTE
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Low Frequency ◽  
Low Frequency Stimulation ◽  
Tryptic Cleavage ◽  
Fast Twitch Muscle ◽  
Frequency Stimulation ◽  
Partial Inactivation ◽  
Fast Twitch ◽  
Stimulation Of

scholarly journals Neural control of gene expression in skeletal muscle. Calcium-sequestering proteins in developing and chronically stimulated rabbit skeletal muscles

1986 ◽  
Vol 239 (2) ◽  
pp. 295-300 ◽  
Author(s):  
E Leberer ◽  
U Seedorf ◽  
D Pette
Keyword(s):  
Neural Control ◽  
Low Frequency ◽  
Neuron Activity ◽  
Control Of Gene Expression ◽  
Low Frequency Stimulation ◽  
Fast Twitch Muscle ◽  
Frequency Stimulation ◽  
Slow Twitch ◽  
Fast Twitch

Tissue contents of the sarcoplasmic-reticulum Ca2+-ATPase (Ca2+ +Mg2+-dependent ATPase), of calsequestrin and of parvalbumin were immunochemically quantified in homogenates of fast- and slow-twitch muscles of embryonic, maturing and adult rabbits. Unlike parvalbumin, Ca2+-ATPase and calsequestrin were expressed in embryonic muscles. Presumptive fast-twitch muscles displayed higher contents of these two proteins than did presumptive slow-twitch muscles. Calsequestrin steeply increased before birth and reached adult values in the two muscle types 4 days after birth. The main increase in Ca2+-ATPase occurred during the first 2 weeks after birth. Denervation of postnatal fast- and slow-twitch muscles decreased calsequestrin to amounts typical of embryonic muscle and suppressed further increases of Ca2+-ATPase. Denervation caused slight decreases in Ca2+-ATPase in adult fast-twitch, but not in slow-twitch, muscles, whereas calsequestrin was greatly decreased in both. Chronic low-frequency stimulation induced a rapid decrease in parvalbumin in fast-twitch muscle, which was preceded by a drastic decrease in the amount of its polyadenylated RNA translatable in vitro. Tissue amounts of Ca2+-ATPase and calsequestrin were essentially unaltered up to periods of 52 days stimulation. These results indicate that in fast- and slow-twitch muscles different basal amounts of Ca2+-ATPase and calsequestrin are expressed independent of innervation, but that neuromuscular activity has a modulatory effect. Conversely, the expression of parvalbumin is greatly enhanced by phasic, and drastically decreased by tonic, motor-neuron activity.

Calcium transients in single fibers of low-frequency stimulated fast-twitch muscle of rat

1999 ◽  
Vol 277 (6) ◽  
pp. C1122-C1129 ◽  
Author(s):  
Stefanie Carroll ◽  
Pierluigi Nicotera ◽  
Dirk Pette
Keyword(s):  
Rate Constant ◽  
Binding Capacity ◽  
Low Frequency ◽  
Partial Recovery ◽  
Single Fibers ◽  
Low Frequency Stimulation ◽  
Fast Twitch Muscle ◽  
Frequency Stimulation ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Ca2+transients were investigated in single fibers isolated from rat extensor digitorum longus muscles exposed to chronic low-frequency stimulation for different time periods up to 10 days. Approximately 2.5-fold increases in resting Ca2+ concentration ([Ca2+]) were observed 2 h after stimulation onset and persisted throughout the stimulation period. The elevated [Ca2+] levels were in the range characteristic of slow-twitch fibers from soleus muscle. In addition, we noticed a transitory elevation of the integral [Ca2+] per pulse with a maximum (∼5-fold) after 1 day. Steep decreases in rate constant of [Ca2+] decay could be explained by an immediate impairment of Ca2+ uptake and, with longer stimulation periods, by an additional loss of cytosolic Ca2+ binding capacity resulting from a decay in parvalbumin content. A partial recovery of the rate constant of [Ca2+] decay in 10-day stimulated muscle could be explained by an increasing mitochondrial contribution to Ca2+ sequestration.

Altered gene expression in fast-twitch muscle induced by chronic low-frequency stimulation

1992 ◽  
Vol 262 (3) ◽  
pp. R333-R338 ◽  
Author(s):  
D. Pette ◽  
S. Dusterhoft
Keyword(s):  
Fiber Type ◽  
Low Frequency ◽  
Protein Isoforms ◽  
Control Factor ◽  
Phenotypic Properties ◽  
Altered Expression ◽  
Low Frequency Stimulation ◽  
Fast Twitch Muscle ◽  
Frequency Stimulation ◽  
Fast Twitch

Increased neuromuscular activity via chronic low-frequency stimulation induces multiple fast-to-slow transitions in phenotypic properties that ultimately lead to fiber type conversions in the fast-twitch muscle of small mammals. Most of these alterations occur in an ordered sequence and result from the sequentially altered expression of myofibrillar and other protein isoforms. These changes relate to altered levels of specific mRNAs, followed by alterations in protein synthesis. As shown by the exchange of myosin heavy chain isoforms, protein degradation may be an additional control factor involved in the rearrangement of the myofibrillar apparatus. The degree of the various fast-to-slow transitions is species dependent and may be related to differences in thyroid hormone levels. It is suggested that the drastically and persistently depressed phosphorylation potential of the ATP system possibly serves to trigger the transformation process.

Creatine loading elevates the intracellular phosphorylation potential and alters adaptive responses of rat fast-twitch muscle to chronic low-frequency stimulation

2015 ◽  
Vol 40 (7) ◽  
pp. 671-682 ◽  
Author(s):  
Charles T. Putman ◽  
Maria Gallo ◽  
Karen J.B. Martins ◽  
Ian M. MacLean ◽  
Michelle J. Jendral ◽  
...  
Keyword(s):  
Low Frequency ◽  
Adaptive Responses ◽  
Slow Fibre ◽  
Phosphorylation Potential ◽  
Time To Peak ◽  
Low Frequency Stimulation ◽  
Fast Twitch Muscle ◽  
Frequency Stimulation ◽  
Induced Changes ◽  
Fast Twitch

This study tested the hypothesis that elevating the intracellular phosphorylation potential (IPP = [ATP]/[ADP]free) within rat fast-twitch tibialis anterior muscles by creatine (Cr) loading would prevent fast-to-slow fibre transitions induced by chronic low-frequency electrical stimulation (CLFS, 10 Hz, 12 h/day). Creatine-control and creatine-CLFS groups drank a solution of 1% Cr + 5% dextrose, ad libitum, for 10 days before and during 10 days of CLFS; dextrose-control and dextrose-CLFS groups drank 5% dextrose. Cr loading increased total Cr (P < 0.025), phosphocreatine (PCr) (P < 0.003), and the IPP (P < 0.0008) by 34%, 45%, and 64%, respectively. PCr and IPP were 46% (P < 0.002) and 76% (P < 0.02) greater in creatine-CLFS than in dextrose-CLFS. Higher IPP was confirmed by a 58% reduction in phospho-AMP-activated protein kinase α (Thr172) (P < 0.006). In dextrose-CLFS, myosin heavy chain (MyHC) I and IIa transcripts increased 32- and 38-fold (P < 0.006), respectively, whereas MyHC-IIb mRNA decreased by 75% (P < 0.03); the corresponding MyHC-I and MyHC-IIa protein contents increased by 2.0- (P < 0.03) and 2.7-fold (P < 0.05), respectively, and MyHC-IIb decreased by 30% (P < 0.03). In contrast, within creatine-CLFS, MyHC-I and MyHC-IIa mRNA were unchanged and MyHC-IIb mRNA decreased by 75% (P < 0.003); the corresponding MyHC isoform contents were not altered. Oxidative reference enzymes were similarly elevated (P < 0.01) in dextrose-CLFS and creatine-CLFS, but reciprocal reductions in glycolytic reference enzymes occurred only in dextrose-CLFS (P < 0.02). Preservation of the glycolytic potential and greater SERCA2 and parvalbumin contents in creatine-CLFS coincided with prolonged time to peak tension and half-rise time (P < 0.01). These results highlight the IPP as an important physiological regulator of muscle fibre plasticity and demonstrate that training-induced changes typically associated with improvements in muscular endurance or increased power output are not mutually exclusive in Cr-loaded muscles.

Effects of low-frequency stimulation of the superior colliculus on spontaneous and visually guided saccades

1993 ◽  
Vol 69 (3) ◽  
pp. 953-964 ◽  
Author(s):  
P. W. Glimcher ◽  
D. L. Sparks
Keyword(s):  
Superior Colliculus ◽  
Time Course ◽  
Low Frequency ◽  
Arbitrary Point ◽  
Visually Guided ◽  
Spontaneous Movements ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Current ◽  
Stimulation Of

1. The first experiment of this study determined the effects of low-frequency stimulation of the monkey superior colliculus on spontaneous saccades in the dark. Stimulation trains, subthreshold for eliciting short-latency fixed-vector saccades, were highly effective at biasing the metrics (direction and amplitude) of spontaneous movements. During low-frequency stimulation, the distribution of saccade metrics was biased toward the direction and amplitude of movements induced by suprathreshold stimulation of the same collicular location. 2. Low-frequency stimulation biased the distribution of saccade metrics but did not initiate movements. The distribution of intervals between stimulation onset and the onset of the next saccade did not differ significantly from the distribution of intervals between an arbitrary point in time and the onset of the next saccade under unstimulated conditions. 3. Results of our second experiment indicate that low-frequency stimulation also influenced the metrics of visually guided saccades. The magnitude of the stimulation-induced bias increased as stimulation current or frequency was increased. 4. The time course of these effects was analyzed by terminating stimulation immediately before, during, or after visually guided saccades. Stimulation trains terminated at the onset of a movement were as effective as stimulation trains that continued throughout the movement. No effects were observed if stimulation ended 40–60 ms before the movement began. 5. These results show that low-frequency collicular stimulation can influence the direction and amplitude of spontaneous or visually guided saccades without initiating a movement. These data are compatible with the hypothesis that the collicular activity responsible for specifying the horizontal and vertical amplitude of a saccade differs from the type of collicular activity that initiates a saccade.

Sign in / Sign up

Export Citation Format

Share Document