To investigate the expression of phospholipase C-gamma1 (PLC-gamma1) in mouse embryonic tissues, serial tissue sections were prepared routinely for immunocytochemistry for PLC-gamma1. The results showed that PLC-gamma1 was expressed in the cartilage, skeletal muscles, myocardium, the collecting tubule of the kidney, connective tissues and the brain, suggesting the important role PLC-gamma1 and the related signal pathway may play in the development of mouse embryonic tissues.
Animals ; Brain ; embryology ; enzymology ; Cartilage ; embryology ; enzymology ; Embryo, Mammalian ; enzymology ; Female ; Fetal Heart ; enzymology ; Immunohistochemistry ; Kidney ; embryology ; enzymology ; Mice ; Muscle, Skeletal ; embryology ; enzymology ; Phospholipase C gamma ; biosynthesis ; Pregnancy

The elevated plasma level of thyroxin and/or triiodothyronine in hyperthyroidism not only induces a transition from the innervated slow-twitch muscle fibers to fast-twitch fibers, but also changes the contractile function in transition muscle fibers. So the muscle weakness of thyrotoxic myopathy would relate to alteration in fatigability of tetanic contraction in muscles, especially in slow-twitch fibers. The aim of the present study was to observe the extent of fatigue of soleus in 4-week hyperthyroid rats and elucidate its underlying mechanism. The isolated soleus muscle strips were perfused in Krebs-Henseleit solution with or without an inhibitor of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA), cyclopiazonic acid (CPA). The contractile function of soleus was observed in twitch and intermittent tetanic contraction. The body weight in 4-week hyperthyroid rats decreased as compared with that in the control group [(292±13) g vs (354±10) g], but there was no difference between hyperthyroid and control groups in the wet weight of soleus [(107.3±8.6) mg vs (115.1±6.9) mg]. The time to peak tension (TPT) and time from peak tension to 75% relaxation (TR(75)) in twitch contraction were shortened in the soleus of hyperthyroid rats, and the TR(75) of tetanic contraction was also shortened as compared with that in the control group [(102.8±4.1) ms vs (178.8±15.8) ms]. The optimal stimulation frequency at which a maximal tension of tetanic contraction happened was shifted from 100 Hz in the control group to 140 Hz in hyperthyroid group. The soleus of hyperthyroid rat was easier to fatigue than that of the control rat during intermittent tetanic contraction. The SERCA activity also increased in soleus of hyperthyroid rat. The TR(75) in tetanic contraction was prolonged and showed an increased fatigue resistance in the soleus of control and hyperthyroid groups treated with 1.0 μmol/L CPA. The fatigue resistance of tetanic contraction in the soleus of hyperthyroid rat increased further with 5.0 μmol/L CPA treatment, but the resting tension kept rising. The 10 μmol/L CPA reduced the fatigue resistance of tetanic contraction in the soleus of hyperthyroid rat. The above results demonstrate that the SERCA activity in soleus can also influence the relaxation duration of twitch contraction like that in the myocardium. The SERCA activity in slow-twitch fibers is possibly involved in the regulation of fatigue resistance of intermittent tetanic contraction.
Animals ; Fatigue ; Glucose ; Hyperthyroidism ; enzymology ; In Vitro Techniques ; Muscle Contraction ; Muscle Fibers, Slow-Twitch ; enzymology ; physiology ; Muscle, Skeletal ; enzymology ; physiology ; Rats ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; metabolism ; Tromethamine

Adenosine Triphosphatases ; metabolism ; Animals ; Antioxidants ; metabolism ; Muscle, Skeletal ; drug effects ; enzymology ; Rats ; Sulfinic Acids ; pharmacology

Animals ; Carnitine ; pharmacology ; H(+)-K(+)-Exchanging ATPase ; metabolism ; Mitochondria, Muscle ; enzymology ; Muscle, Skeletal ; drug effects ; Physical Conditioning, Animal ; Rats

Although light microscopic features of muscle are not pathognomonic in most cases of myasthenia gravis (MG), careful examination of neuromuscular junction by electron microscopy (EM) can reveal important clues for this disease. We report here a case of MG confirmed by EM study to emphasize that tissue diagnosis is still the best adjuvant to confirm the diagnosis. An 18-year-old female visited our hospital complaining of progressive muscle weakness for 3 years. She had difficulty in running, going upstairs and doing routine activities. Symptoms were aggravated with continuous work and resolved after rest. She had weakness of bilateral masseter and facial muscles and proximal portions of extremities without definite diurnal variation. Electromyography showed myopathic changes in proximal muscles of extremities. MG was considered but tensilon test was equivocal. Repetitive nerve stimulation tests revealed 20-30 percent decrease in responses to low and high rate stimulation. Muscle biopsy revealed selective type 2 atrophy. Ultrastructurally, abnormalities of neuromuscular junctions, i.e., wide primary synaptic cleft, and wide and shallow secondary synaptic clefts with mild myopathic features were present. These findings were pathognomonic for MG. Later, her symptoms were improved completely 3 months after thymectomy. The histologic finding of thymus was follicular hyperplasia.
Adolescence ; Biopsy ; Case Report ; Female ; Human ; Microscopy, Electron ; Mitochondria/ultrastructure ; Mitochondria/pathology ; Muscle, Skeletal/ultrastructure ; Muscle, Skeletal/pathology ; Muscle, Skeletal/enzymology ; Myasthenia Gravis/pathology* ; Myofibrils/ultrastructure ; Myofibrils/pathology ; Myosin ATPase/analysis ; Neuromuscular Junction/ultrastructure* ; Neuromuscular Junction/pathology*

Although light microscopic features of muscle are not pathognomonic in most cases of myasthenia gravis (MG), careful examination of neuromuscular junction by electron microscopy (EM) can reveal important clues for this disease. We report here a case of MG confirmed by EM study to emphasize that tissue diagnosis is still the best adjuvant to confirm the diagnosis. An 18-year-old female visited our hospital complaining of progressive muscle weakness for 3 years. She had difficulty in running, going upstairs and doing routine activities. Symptoms were aggravated with continuous work and resolved after rest. She had weakness of bilateral masseter and facial muscles and proximal portions of extremities without definite diurnal variation. Electromyography showed myopathic changes in proximal muscles of extremities. MG was considered but tensilon test was equivocal. Repetitive nerve stimulation tests revealed 20-30 percent decrease in responses to low and high rate stimulation. Muscle biopsy revealed selective type 2 atrophy. Ultrastructurally, abnormalities of neuromuscular junctions, i.e., wide primary synaptic cleft, and wide and shallow secondary synaptic clefts with mild myopathic features were present. These findings were pathognomonic for MG. Later, her symptoms were improved completely 3 months after thymectomy. The histologic finding of thymus was follicular hyperplasia.
Adolescence ; Biopsy ; Case Report ; Female ; Human ; Microscopy, Electron ; Mitochondria/ultrastructure ; Mitochondria/pathology ; Muscle, Skeletal/ultrastructure ; Muscle, Skeletal/pathology ; Muscle, Skeletal/enzymology ; Myasthenia Gravis/pathology* ; Myofibrils/ultrastructure ; Myofibrils/pathology ; Myosin ATPase/analysis ; Neuromuscular Junction/ultrastructure* ; Neuromuscular Junction/pathology*

AIMTo study the effect of radix-astragali compound(RC) on muscle atrophy in tail-suspended rats. Muscle weight, fiber type distribution, cross-sectional area (CSA), and activity of myosin adenosine triphosphatase (ATPase) in rat soleus muscle were investigated.

METHODSThe tail-suspended rats were subjected to a 14 days simulated weightlessness, during which period, RC or saltwater was given via intragastric instillation during tail suspension. The changes of soleus muscle weight were scaled by muscle-to-body weight ratio. The activities of myosin ATPase of muscle fibers were detected by method of Ca(2+) -ATPase.

RESULTSAfter a 14 days tail suspension it was found: in rats treated with RC, soleus muscle-to-body weight ratio rose by 33.33% (P < 0.01), both CSA of type I and II fiber drastically enhanced by(143.03%, P < 0.01; 83.25%, P < 0.01), the percentage of type I fiber significantly declined compared to the untreated rats.

CONCLUSIONRC is able to effectively prevent muscle atrophy caused by tail suspension and restrain the increase in the myosin ATPase activities caused by simulated weightlessness.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Hindlimb Suspension ; Male ; Muscle Fibers, Skeletal ; enzymology ; Muscle, Skeletal ; drug effects ; enzymology ; Muscular Atrophy ; prevention & control ; Myosins ; metabolism ; Rats ; Rats, Sprague-Dawley ; Weightlessness Simulation ; methods

OBJECTIVETo explore the possible mechanism of the erector spinal muscles in idiopathic scoliosis by comparing the expression and localization of neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) of the thoracic erector spinal muscles on convex side and concave side.

METHODSThe patient group comprised 8 females and 2 males who were scheduled for spinal surgery. The apex of scoliotic curve in these patients arose between T6 and T11. The mean age was 14.3 (range 12-17) years, and the mean Cobb angle was 57.7 degrees (range 45 degrees-85 degrees). Muscle biopsies were taken bilaterally during surgery from the superficial multifidus muscle at the apex of the curve between the 6th and 11th thoracic vertebral levels. Part of the tissue was fixed in formalin and stained with hematoxylin and eosin; the remaining tissue was snap frozen and processed for immunohistochemistry and Western blot. Immunocytochemistry for nNOS and iNOS were performed using the EnVision two-step method. Western blot was done with antibodys to nNOS and iNOS. Immunoreactive bands were visualized by enhanced chemiluminescence according to the manufacturer's specifications (Amersham Corp).

RESULTSnNOS protein in the erector spinal muscles was localized at the sarcolemma. Western blot demonstrated that nNOS protein expression in the concave side of erector spinal muscles is more than that in the convex side. A significant decrease in nNOS protein and activity was found on the convex side of erector spinal muscles from idiopathic scoliosis patients; There was a little immunoreactivity to iNOS in erector spinal muscles. There was little difference in iNOS protein expression between both sides of the curve. Western blot detected the same results.

CONCLUSIONThere is a greater expression of nNOS and iNOS on the concave side than on the convex side, suggesting nNOS and iNOS may play a role in the pathogenesis of idiopathic scoliosis.

Adolescent ; Child ; Female ; Humans ; Immunohistochemistry ; Male ; Muscle, Skeletal ; cytology ; enzymology ; Nitric Oxide Synthase ; analysis ; metabolism ; Nitric Oxide Synthase Type I ; Nitric Oxide Synthase Type II ; Scoliosis ; enzymology

The plateau pika (Ochotona curzoniae) and plateau zokor (Myospalax baileyi) are specialized native species of the Qinghai-Tibetan plateau. The goal of this study was to examine physiological differences in skeletal muscle glycolysis and hepatic lactate metabolism between these two species. The partial sequence of pyruvate carboxylase (PC) gene was cloned and sequenced. The mRNA expression levels of PC and lactate dehydrogenases (LDH-A, LDH-B) were determined by real-time PCR. The enzymatic activity of PC was measured using malic acid coupling method. The concentration of lactic acid (LD) and the specific activities of LDH in liver and skeletal muscle of two species were measured. The different isoenzymes of LDH were determined by native polyacrylamide gel electrophoresis (PAGE). The results showed that, (1) LDH-B mRNA level in skeletal muscle of plateau zokor was significantly higher than that of plateau pika (P < 0.01), but no differences was found at LDH-A mRNA levels between them (P > 0.05); (2) PC, LDH-A and LDH-B mRNA levels in liver of plateau pika were significantly higher than those of plateau zokor (P < 0.01); (3) The LDH activity and concentration of LD in skeletal muscle and liver, as well as the PC activity in liver of plateau pika were significantly higher than those of plateau zokor (P < 0.01); (4) The isoenzymatic spectrum of lactate dehydrogenase showed that the main LDH isoenzymes were LDH-A4, LDH-A3B and LDH-A2B2 in skeletal muscle of plateau pika, while the main LDH isoenzymes were LDH-AB3 and LDH-B4 in skeletal muscle of plateau zokor; the main isoenzymes were LDH-A3B, LDH-A2B2, LDH-AB3 and LDH-B4 in liver of plateau pika, while LDH-A4 was the only isoenzyme in liver of plateau zokor. These results indicate that the plateau pika gets most of its energy for sprint running through enhancing anaerobic glycolysis, producing more lactate in their skeletal muscle, and converting lactate into glucose and glycogen in the liver by enhancing gluconeogenesis. As a result, the plateau pika has a reduced dependence on oxygen in its hypoxic environment. In contrast, plateau zokor derives most of its energy used for digging activity by enhancing aerobic oxidation in their skeletal muscle, although they inhabit hypoxic underground burrows.
Animals ; Glycolysis ; Hypoxia ; metabolism ; Isoenzymes ; metabolism ; L-Lactate Dehydrogenase ; metabolism ; Lactic Acid ; metabolism ; Lagomorpha ; physiology ; Liver ; enzymology ; Muscle, Skeletal ; enzymology ; Oxygen ; metabolism ; RNA, Messenger

OBJECTIVETo explore the effect of glucose and/or acanthopanacis senticosi administration supplement on AMP-activated protein kinase (AMPK) activation and its change in different phase after exercise in muscle cell of rat.

METHODS128 rats were divided into exercise control groups (C groups), exercise and glucose administration groups (G groups), exercise and acanthopanacis senticosi administration groups (A groups), exercise and glucose and acanthopanacis senticosi administration groups (GA groups). The glucose and acanthopanacis senticosi supplement were completed by intragastric administration in half hour after exercise. All rats were killed in different designed time points before or after glycogen depletion exercise (0 h, 4 h and 12 h respectively) and finally divided into 16 groups (n = 8). The values of AMPK in soleus muscle were analyzed by Western blot.

RESULTS(1) After exercise, the protein content of AMPK quickly increased and reached the peak (209.23 +/- 21.32) then gradually decreased. (2) Acanthopanacis senticosi administration markedly increased the protein content of AMPK in the 0 h and 4 h points after glycogen consumption training (225.11 +/- 20.58 and 186.31 +/- 15.26 vs 195.19 +/- 13.31 and 157.11 +/- 16.43) without any difference after 12 h. (3) Glucose administration had no significant effect on AMPK activation. (4) Both glycogen and acanthopanacis senticosi were supplied simultaneously that had enhanced the AMPK content in 4 h and 12 h point (217.96 +/- 19.25 and 191.86 +/- 14.69). However, the AMPK content in GA group was lower than that in the C groups at 12 h point (121.89 +/- 15.23 vs 137.92 +/- 16.01).

CONCLUSIONExercise could markedly activate the AMPK protein in muscle cell and acanthopanacis senticosi administration augmented such activation. Glucose administration had no significant effect on AMPK activation.

AMP-Activated Protein Kinases ; metabolism ; Animals ; Drugs, Chinese Herbal ; pharmacology ; Eleutherococcus ; Glucose ; pharmacology ; Male ; Muscle Cells ; drug effects ; enzymology ; Muscle, Skeletal ; cytology ; drug effects ; enzymology ; Physical Conditioning, Animal ; Rats ; Rats, Sprague-Dawley