Changes of skeletal muscle proteases activities during a chronic low-frequency stimulation period

2001 ◽  
Vol 442 (5) ◽  
pp. 745-751 ◽  
Author(s):  
Matilde Parreño ◽  
Albert Pol ◽  
Joan Cadefau ◽  
Joan Parra ◽  
Luisa Alvarez ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Low Frequency ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Period

scholarly journals Short-Term Amygdala Low-Frequency Stimulation Does not Influence Hippocampal Interneuron Changes Observed in the Pilocarpine Model of Epilepsy

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 520
Author(s):  
István Mihály ◽  
Tímea Molnár ◽  
Ádám-József Berki ◽  
Réka-Barbara Bod ◽  
Károly Orbán-Kis ◽  
...  
Keyword(s):  
Cell Density ◽  
Basolateral Amygdala ◽  
Low Frequency ◽  
Low Frequency Stimulation ◽  
Male Wistar Rats ◽  
Pilocarpine Model ◽  
Frequency Stimulation ◽  
Stimulation Period ◽  
Oxide Synthase ◽  
Deep Brain

Temporal lobe epilepsy (TLE) is characterized by changes in interneuron numbers in the hippocampus. Deep brain stimulation (DBS) is an emerging tool to treat TLE seizures, although its mechanisms are not fully deciphered. We aimed to depict the effect of amygdala DBS on the density of the most common interneuron types in the CA1 hippocampal subfield in the lithium-pilocarpine model of epilepsy. Status epilepticus was induced in male Wistar rats. Eight weeks later, a stimulation electrode was implanted to the left basolateral amygdala of both pilocarpine-treated (Pilo, n = 14) and age-matched control rats (n = 12). Ten Pilo and 4 control animals received for 10 days 4 daily packages of 50 s 4 Hz regular stimulation trains. At the end of the stimulation period, interneurons were identified by immunolabeling for parvalbumin (PV), neuropeptide Y (NPY), and neuronal nitric oxide synthase (nNOS). Cell density was determined in the CA1 subfield of the hippocampus using confocal microscopy. We found that PV+ cell density was preserved in pilocarpine-treated rats, while the NPY+/nNOS+ cell density decreased significantly. The amygdala DBS did not significantly change the cell density in healthy or in epileptic animals. We conclude that DBS with low frequency applied for 10 days does not influence interneuron cell density changes in the hippocampus of epileptic rats.

Selected Contribution: Low-frequency stimulation of fast muscle affects the abundance of Ca2+-ATPase but not its oligomeric status

2001 ◽  
Vol 90 (1) ◽  
pp. 371-379 ◽  
Author(s):  
Shona Harmon ◽  
Gabriele R. Froemming ◽  
Elmi Leisner ◽  
Dirk Pette ◽  
Kay Ohlendieck
Keyword(s):  
Skeletal Muscle ◽  
Protein Interactions ◽  
Low Frequency ◽  
Transition Process ◽  
Fast Muscle ◽  
Rapid Decline ◽  
Ion Pump ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Rapid Stimulation

After chronic, low-frequency stimulation, a rapid decline in Ca2+ pump activity is observed during the early stages of skeletal muscle transformation. However, this variation in enzymatic activity does not coincide with a drastic reduction in the amount of sarcoplasmic reticulum Ca2+-ATPases. To investigate whether changes in subunit interactions within Ca2+ pump complexes contribute to this phenomena, we performed a chemical cross-linking analysis of 4 days continuously, and 4 days discontinuously, electrostimulated fast muscle fibers. The abundance of the slow and fast Ca2+-ATPase isoforms sarco(endo)plasmic reticulum Ca2+- ATPase types 1 and 2 was affected during the fast-to-slow transition process, demonstrating that, even after short-term stimulation, distinct changes in the isoform expression pattern of muscle proteins occur. However, the oligomeric status of both ion pump species did not change. Hence, chemical modifications of critical enzyme domains must be responsible for the rapid stimulation-induced activity changes, not variations in protein-protein interactions within Ca2+-ATPase units. Oligomerization appears to be of central importance to the proper physiological functioning of the Ca2+-ATPase and does not undergo changes during skeletal muscle conditioning.

scholarly journals Salbutamol and chronic low-frequency stimulation of canine skeletal muscle.

1996 ◽  
Vol 496 (1) ◽  
pp. 221-227 ◽  
Author(s):  
P Hu ◽  
K M Zhang ◽  
J J Feher ◽  
S W Wang ◽  
L D Wright ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Low Frequency ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Of

scholarly journals Calpain activity in fast, slow, transforming, and regenerating skeletal muscles of rat

2000 ◽  
Vol 279 (3) ◽  
pp. C639-C647 ◽  
Author(s):  
Karim R. Sultan ◽  
Bernd T. Dittrich ◽  
Dirk Pette
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Low Frequency ◽  
Protein Isoforms ◽  
Calpain Activity ◽  
Adult Skeletal Muscle ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Edl Muscle

Fiber-type transitions in adult skeletal muscle induced by chronic low-frequency stimulation (CLFS) encompass coordinated exchanges of myofibrillar protein isoforms. CLFS-induced elevations in cytosolic Ca2+ could activate proteases, especially calpains, the major Ca2+-regulated cytosolic proteases. Calpain activity determined by a fluorogenic substrate in the presence of unaltered endogenous calpastatin activities increased twofold in low-frequency-stimulated extensor digitorum longus (EDL) muscle, reaching a level intermediate between normal fast- and slow-twitch muscles. μ- and m-calpains were delineated by a calpain-specific zymographical assay that assessed total activities independent of calpastatin and distinguished between native and processed calpains. Contrary to normal EDL, structure-bound, namely myofibrillar and microsomal calpains, were abundant in soleus muscle. However, the fast-to-slow conversion of EDL was accompanied by an early translocation of cytosolic μ-calpain, suggesting that myofibrillar and microsomal μ-calpain was responsible for the twofold increase in activity and thus involved in controlled proteolysis during fiber transformation. This is in contrast to muscle regeneration where m-calpain translocation predominated. Taken together, we suggest that translocation is an important step in the control of calpain activity in skeletal muscle in vivo.

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