Chemical constituents in ethyl acetate and butanol fractions of ethanol extracts from Acorus tatarinowii were separated by column chromatography. Bufo skeletal muscle fatigue model was established to study the anti-fatigue activity of separated compounds. Five compounds were separated and identified by spectroscopic analysis as acoramone(1),cycloartenone(2),2,4,5-trimethoxyl-2'-butoxy-1,2-phenyl propandiol(3),5-hydroxymethyl furfural(4), and 5-butoxymethyl furfural(5). Compound 3 was a new compound, and compounds 2 and 5 were separated from this plant for the first time. Compound 4 exhibited a notable anti-fatigue activity.
Acorus ; chemistry ; Animals ; Bufonidae ; Fatigue ; drug therapy ; Muscle, Skeletal ; drug effects ; Plant Extracts ; chemistry ; pharmacology

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

AIMIn order to elucidate the underlying mechanism of depressed maximal isometric twitch tension normalized by cross sectional area of muscle strip in unloaded soleus.

METHODSThe soleus and extensor digitorum longus (EDL) muscle strips were perfused in vitro and treated by 2,3-Butanedione monoxime (BDM).

RESULTSThe BDM decreased Pt of soleus and EDL in a concentration-dependent manner. The Pt could restored completely to normal level after washing out BDM. The isometric twitch duration was not altered during 1 mmol/L BDM of perfusion, but was shortened at 10 mmol/L dose. The time from maximal to half Pt in EDL was shorter than that in soleus during 10 mmol/L BDM of perfusion. The inhibitory effects of BDM on myosin ATPase activity were higher in EDL than in soleus. The inhibitory extent of BDM on myosin ATPase activity of soleus and EDL was lower than that on Pt.

CONCLUSIONThese results suggest that reduction in cross-bridge function of skeletal muscle may be one of reasons induced a decrease in its Pt. BDM is not a specific inhibitor on myosin ATPase activity and can affect multiple parts of excitation-contraction coupling in skeletal muscle.

Animals ; Diacetyl ; analogs & derivatives ; pharmacology ; Isometric Contraction ; drug effects ; physiology ; Male ; Muscle Contraction ; drug effects ; physiology ; Muscle, Skeletal ; drug effects ; physiology ; Myosins ; antagonists & inhibitors ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effect of ascorbic acid (VC) on relaxation of ex vivo Bufo gastrocnemius during sustained isometric contraction.

METHODSDynamic tension of the muscle was recorded under constant voltage stimulation within 7.0 min at 2 s intervals. The rest tension and relaxation rate of the muscle was obtained by weighted fitting to the relaxation process of tension <90% of its peak with a mono-exponential model to characterize the muscular relaxation.

RESULTSVC at 2.0 mmol/L alone or in combination with the inhibitors of the antixoidation enzymes (surperoxide dismutase, glutathione peroxidase and catalase) resulted in negligible alterations in the muscular relaxation kinetics. VC combined with the inhibitor of surperoxide dismutase resulted in significantly lowered relaxation rate while increased rest tension, but VC with the inhibitor of either catalase or glutathione peroxidase showed negligible action. VC combined with the inhibitors of all the 3 enzymes also caused significant effect on the muscular relaxation kinetics, which was similar the effect of VC with superoxide dismutase inhibitor.

CONCLUSIONVC at high concentration may result in oxidative toxicity to the biological system rich in transitional metal ion complexes but with low antioxidation capacity by causing superoxide-mediated oxidative damages.

Animals ; Ascorbic Acid ; pharmacology ; Bufonidae ; Electric Stimulation ; In Vitro Techniques ; Isometric Contraction ; drug effects ; Muscle Relaxation ; drug effects ; Muscle, Skeletal ; drug effects ; physiology

UNLABELLEDTo study the effects of Bupivacaine and hyaluronidase on the proliferation of adult rat muscle satellite cells in vivo.

METHODSImmunohistochemistry, hematoxylin and eosin staining, electron micrograph were used.

RESULTS(1) There are few rare desmin positive satellite cells lie in the myofibers of control group and Sterile saline group which are still continual. MMD of control and Sterile saline group is 0.66% +/- 0.57% and 2.48% +/- 1.13% respectively. Sterile saline group has no significant difference than that of the control (P > 0.05). (2) The myofibers of hyaluronidase group are basically continual. The number of desmin positive satellite cells are increased. MMD of Hyaluronidase is 2.52% +/- 1.41% which has no remarkable difference than that of the Sterile saline (P > 0.05). (3) Plentiful necrosis and degeneration myofibers can been seen in Bupivacaine group and Hyaluronidase + Bupivacaine group coinciding with the activation and proliferation of muscle satellite cells. The number of Desmin positive satellite cells are increased significantly and some of which have formed myotubes. MMD of Bupivacaine and Hyaluronidase + Bupivacaine is 19.01% +/- 4.74% and 22.41% +/- 7.64% respectively which have significant change than that of Sterile saline (P < 0.01).

CONCLUSIONThe local anaesthetic Bupivacaine can induce the significant proliferation of myoblasts and the formation of myotubes in vivo. Hyaluronidase has no significant effect on the proliferation of satellite cells in vivo under this experimental condition.

Animals ; Bupivacaine ; pharmacology ; Cell Proliferation ; drug effects ; Hyaluronoglucosaminidase ; pharmacology ; Male ; Rats ; Rats, Wistar ; Satellite Cells, Skeletal Muscle ; drug effects

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

OBJECTIVETo study the effects of insulin on the proteolysis of cultured rabbit skeletal muscular myotubes in vitro, and their possible mechanisms.

METHODSMuscles of lower limbs of juvenile rabbits were isolated for tissue-block culture. After passage, myoblasts were formed and fused into myotubes. Then the protein in myotubes was radiolabelled with L-[ 3,5-3H] tyrosine. The myotubes were cultured in DMEM medium containing 100 nmol/L insulin (n = 24, group B) , 100 nmol/L dexamethasone (n = 24, group C) , 100 nmol/L insulin and 100 nmol/L dexamethasone (n = 24, group D) , no insulin or dexamethasone (n =24, group A), respectively. Twenty-four hours after culture, the L-[3,5-3H] tyrosine content in culture medium and cells were determined, and the degradation rates of protein were calculated. The mRNA expressions of ubiquitin and protease C2 subunit were determined by Northern blot.

RESULTSThe degradation rates of myotube protein in group A(0. 38+/-0.04) was obviously lower than that in group C (0.50+/-0.03, P <0.01), but it was obviously higher than that in group B(0. 35+/-0.03, P <0.05). Though the degradation rates of myotube protein in group D (0.41+/-0. 03) was evidently lower than that in group C ( P < 0.01) , it was still higher than that in group A( P < 0.05 ). The mRNA expressions of ubiquitin and protease C2 subunit in group A ( the scale: 2. 4 kb ubiquitin was 0. 82+/-0. 15, 1. 2 kb ubiquitin was 0. 60+/-0. 10, C2 subunit was 0. 75+/-0. 16) was obviously lower than that in group C ( the scale: 2.4 kb ubiquitin was 2. 15+/-0. 23, 1.2 kb ubiquitin was 1.50+/-0. 14,C2 subunit was 1.50+/-0. 13 , P <0. 01) , but it in group D was lower than that in group C (the scale: 2. 4 kb ubiquitin was 1. 25+/-0. 17, 1. 2 kb ubiquitin was 0. 85+/-0. 09, C2 subunit was 0. 90+/-0. 15, P <0. 01) , and it was similar to that in group B (the scale: 2.4 kb ubiquitin was 0. 85+/-0.07, 1.2 kb ubiquitin was 0. 65+/- 0. 12, C2 subunit was 0. 76 +/-0. 09, P > 0. 05).

CONCLUSIONThe effects of insulin on the activity of ubiquitin-proteasome pathway and the proteolytic rate in normal myotubes were relatively weak. However, insulin can significantly inhibit the effects of dexamethasone on the gene expressions of ubiquitin system and the proteolytic rate in myotubes, but the mechanism needs further research.

Animals ; Cells, Cultured ; In Vitro Techniques ; Insulin ; pharmacology ; Male ; Muscle Fibers, Skeletal ; drug effects ; metabolism ; Muscle Proteins ; metabolism ; Rabbits ; Ubiquitin ; metabolism

PURPOSE: The purpose of this study was to examine the effect of DHEA (Dehydroepiandrosterone) on muscle weight and Type I and II fiber cross-sectional area of affected and unaffected hindlimb muscles in rats with neuropathic pain induced by unilateral peripheral nerve injury. METHODS: Neuropathic pain was induced by ligation and cutting of the left L5 spinal nerve. Adult male Sprague-Dawley rats were randomly assigned to one of two groups: The DHEA group (n=10) had DHEA injections daily for 14 days, and the Vehicle group (n=10) had vehicle injections daily for 14 days. Withdrawal threshold, body weight, food intake and activity were measured every day. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected from the both hindlimbs. Body weight, food intake, activity, muscle weight and Type I, II fiber cross-sectional area of the dissected muscles were measured. RESULTS: The DHEA group showed significant increases (p<.05), as compared to the vehicle group for muscle weight of the unaffected plantaris, and in Type II fiber cross-sectional area of the gastrocnemius muscle. The DHEA group demonstrated a higher pain threshold than the vehicle group whereas total diet intake and activity score were not significantly different between the two groups. CONCLUSION: DHEA administration for 14 days attenuates unaffected plantaris and gastrocnemius muscle atrophy.
Animals ; Body Weight ; Dehydroepiandrosterone/*administration & dosage ; Disease Models, Animal ; Eating/drug effects ; *Hindlimb ; Male ; Muscle Fibers, Skeletal/*drug effects/pathology ; Muscle, Skeletal/drug effects ; Muscular Atrophy/*drug therapy ; Pain/etiology ; Pain Measurement ; Peripheral Nerves/*injuries ; Rats ; Rats, Sprague-Dawley

Fenofibrate is a drug that has been suggested to inhibit weight gain by increasing the catabolism of fatty acid in the hepatic mitochondria. We hypothesized that fenofibrate induces an increase in energy expenditure in the hepatic mitochondria, which results in the reduction of adipose tissue. In this study we measured hepatic uncoupling protein (UCP)-2, -3, core temperatures and abdominal fat composition with MRI in Otsuka Long-Evans Tokushima Fatty rats. The fenofibrate group (n=7) was fed fenofibrate (320 mg/kg) mixed chow. The control group (n=7) was fed chow only. The body weight (531.6+/-7.6 g) of the fenofibrate group was significantly lower than that (744.3+/-14.9 g) of the control group (p<0.005). The areas of visceral and subcutaneous fat in the fenofibrate group (11.0+/-0.9 cm2, 4.2+/-0.3 cm2) were significantly less than those in the control group (21.0+/-0.7 cm2, 7.4+/-0.4 cm2) (p=0.046, respectively). The esophageal and rectal temperatures of the fenofibrate group (37.7+/-0.1 degrees C, 33.1+/-0.2 degrees C) were significantly higher than those of the control group (37.3+/-0.1 degrees C, 32.2+/-0.1 degrees C) (p=0.025, p=0.005). There was de novo expression of UCP-3 in the liver of the fenofibrate group. These data suggest that increased energy dissipation, via hepatic UCP-3 by fenofibrate, contribute to decreased weight gain in obese rats.
Rats, Inbred OLETF ; Rats ; Procetofen/*pharmacology ; Obesity/*physiopathology ; Muscle, Skeletal/drug effects/physiopathology ; Liver/drug effects/*physiopathology ; Energy Metabolism/*drug effects ; Body Weight/*drug effects ; Body Temperature/*drug effects ; Antilipemic Agents/administration & dosage ; Animals ; Adipose Tissue/*drug effects

Growth Hormone (GH) is an important and powerful metabolic hormone that is secreted in a pulsatile pattern from cells in the anterior pituitary, influenced by several normal and pathophysiological conditions. Human GH was first isolated in the 1950s and human derived cadaveric GH was initially used to treat patients with GH deficiency. However, synthetic recombinant GH has been widely available since the mid-1980s and the advent of this recombinant GH boosted the abuse of GH as a doping agent. Doping with GH is a well-known problem among elite athletes and among people training at gyms, but is forbidden for both medical and ethical reasons. It is mainly the anabolic and, to some extent, the lipolytic effects of GH that is valued by its users. Even though GH's rumour as an effective ergogenic drug among athletes, the effectiveness of GH as a single doping agent has been questioned during the last few years. There is a lack of scientific evidence that GH in supraphysiological doses has additional effects on muscle exercise performance other than those obtained from optimised training and diet itself. However, there might be synergistic effects if GH is combined with, for example, anabolic steroids, and GH seems to have positive effect on collagen synthesis. Regardless of whether or not GH doping is effective, there is a need for a reliable test method to detect GH doping. Several issues have made the development of a method for detecting GH doping complicated but a method has been presented and used in the Olympics in Athens and Turin. A problem with the method used, is the short time span (24-36 hours) from the last GH administration during which the test effectively can reveal doping. Therefore, out-of-competition testing will be crucial.However, work with different approaches to develop an alternative, reliable test is ongoing.
Body Composition ; Bone and Bones ; drug effects ; Doping in Sports ; Growth Hormone ; adverse effects ; pharmacology ; physiology ; Humans ; Lipolysis ; Muscle, Skeletal ; drug effects ; physiology