The effects of exercise-induced fatigue on acetylcholinesterase expression and activity at rat neuromuscular junctions

Training Intensity, Not Duration, May Be Key to Upregulating Presynaptic Proteins of Calcium Dynamics and Calcium-Dependent Exocytosis in Fast- and Slow-Twitch Skeletal Muscles, in Addition to Maintaining Performance After Detraining

Neuromuscular adaptations are essential for improving athletic performance. However, little is known about the effect of different endurance training protocols and their subsequent detraining on the gene expression of critical factors for neuromuscular synaptic transmission. Therefore, this study investigated the effects of endurance training (high-intensity interval training [HIIT], continuous [cEND], mixed interval [Mix], and all protocols combined [Comb]) and detraining on performance and gene expression (GE) of the alpha-1a, synaptotagmin II (Syt-II), synaptobrevin II (Vamp2), and acetylcholinesterase (AChE) in the gastrocnemius and soleus of Wistar rats. Eighty rodents were randomly divided into control, HIIT, cEND, Mix, Comb, and detraining groups. The rodents trained for 6 weeks (5 × /week), followed by 2 weeks of detraining. Performance improved in all training groups and decreased following detraining (p < 0.05), except HIIT. In the gastrocnemius, alpha-1a GE was upregulated in the Mix. Syt-II and AChE GE were upregulated in HIIT, Mix, and Comb. Vamp2 GE was upregulated in all groups. In the soleus, alpha-1a GE was upregulated in HIIT, Mix, and Comb. Syt-II and Vamp2 GE were upregulated in all groups. AChE GE was upregulated in cEND, Mix, and Comb. Detraining downregulated mostly the gene expression in the skeletal muscles. We conclude that training intensity appears to be a key factor for the upregulation of molecules involved in neuromuscular synaptic transmission. Such changes occur to be involved in improving running performance. On the other hand, detraining negatively affects synaptic transmission and performance.

Hyperinsulinemia Induced Altered Insulin Signaling Pathway in Muscle of High Fat- and Carbohydrate-Fed Rats: Effect of Exercise

Insulin resistance is a state of impaired responsiveness to insulin action. This condition not only results in deficient glucose uptake but increases the risk for cardiovascular diseases (CVD), stroke, and obesity. The present work investigates the molecular mechanisms of high carbohydrate and fat diet in inducing prediabetic hyperinsulinemia and effect of exercise on InsR signaling events, muscular AChE, and lactate dehydrogenase activity. Adult male Wistar rats were divided into the control (C) diet group, high-carbohydrate diet (HCD) group, high-fat diet (HFD) group, and HCD and HFD groups with exercise (HCD Ex and HFD Ex, respectively). Acetyl choline esterase activity, lactate dehydrogenase activity, total lactate levels, IRS1 phosphorylations, and Glut4 expression patterns were studied in the muscle tissue among these groups. High carbohydrate and fat feeding led to hyperinsulinemic status with reduced acetylcholine esterase (AChE) activity and impaired phosphorylation of IRS1 along with increased lactate concentrations in the muscle. Exercise significantly upregulated phosphoinositide 3 kinase (PI3K) docking site phosphorylation and downregulated the negative IRS1 phosphorylations thereby increasing the glucose transporter (GLUT) expressions and reducing the lactate accumulation. Also, the levels of second messengers like IP3 and cAMP were increased with exercise. Increased second messenger levels induce calcium release thereby activating the downstream pathway promoting the translocation of GLUT4 to the plasma membrane. Our results showed that the metabolic and signaling pathway dysregulations seen during diet-induced hyperinsulinemia, a metabolic condition seen during the early stages in the development of prediabetes, were improved with vigorous physical exercise. Thus, exercise can be considered as an excellent management approach over drug therapy for diabetes and its complications.

2,3,7,8-Tetrachlorodibenzo-p-dioxin induces alterations in myogenic differentiation of C2C12 cells

Dioxin-induced toxicities that affect the development of the motor system have been proposed since many years. However, cellular evidence and the molecular basis for the effects are limited. In this study, a cultured mouse myoblast cell line, C2C12, was utilized to examine the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on myogenic differentiation and expression of acetylcholinesterase (AChE), a neuromuscular transmission-related gene. The results showed that TCDD exposure at 10^-10 M repressed the myotube formation of C2C12 cells by disturbing the fusion process and suppressing the expression of myosin heavy chain, a myobute structural protein, and not by induction of cytotoxicity. Furthermore, TCDD dose dependently suppressed the transcriptional expression and enzymatic activity of AChE during the myogenic differentiation, particularly in the middle stage. However, the administration of aryl hydrocarbon receptor antagonists, CH223191 and alpha-naphthoflavone, did not completely reverse the TCDD-induced downregulation of muscular AChE during myogenic differentiation. These findings suggest that low dose exposure to dioxin may result in disturbances of muscle differentiation and neuromuscular transmission.

The Effects of Acute Exercise on Mood, Cognition, Neurophysiology, and Neurochemical Pathways: A Review

A significant body of work has investigated the effects of acute exercise, defined as a single bout of physical activity, on mood and cognitive functions in humans. Several excellent recent reviews have summarized these findings; however, the neurobiological basis of these results has received less attention. In this review, we will first briefly summarize the cognitive and behavioral changes that occur with acute exercise in humans. We will then review the results from both human and animal model studies documenting the wide range of neurophysiological and neurochemical alterations that occur after a single bout of exercise. Finally, we will discuss the strengths, weaknesses, and missing elements in the current literature, as well as offer an acute exercise standardization protocol and provide possible goals for future research.

Reduction in Pain and Inflammation Associated With Chronic Low Back Pain With the Use of the Medical Food Theramine

Management of chronic back pain is a challenge for physicians. Although standard treatments exert a modest effect, they are associated with narcotic addiction and serious side effects from nonsteroidal antiinflammatory agents. Moreover, neurotransmitter depletion from both the pain syndrome and therapy may contribute to a poor treatment outcome. Neurotransmitter deficiency may be related both to increased turnover rate and inadequate neurotransmitter precursors from the diet, particularly for essential and semi-essential amino acids. Theramine, an amino acid blend 68405-1 (AAB), is a physician-prescribed only medical food. It contains neurotransmitter precursors and systems for increasing production and preventing attenuation of neurotransmitters. A double-blind controlled study of AAB, low-dose ibuprofen, and the coadministration of the 2 agents were performed. The primary end points included the Roland Morris index and Oswestry disability scale. The cohort included 122 patients aged between 18 and 75 years. The patients were randomized to 1 of 3 groups: AAB alone, ibuprofen alone, and the coadministration of the 2 agents. In addition, C-reactive protein, interleukin 6, and plasma amino acid concentrations were measured at baseline and 28 days time points. After treatment, the Oswestry Disability Index worsened by 4.52% in the ibuprofen group, improved 41.91% in the AAB group, and improved 62.15% in the combination group. The Roland Morris Index worsened by 0.73% in the ibuprofen group, improved by 50.3% in the AAB group, and improved 63.1% in the combination group. C-reactive protein in the ibuprofen group increased by 60.1%, decreased by 47.1% in the AAB group, and decreased by 36% in the combination group. Similar changes were seen in interleukin 6. Arginine, serine, histidine, and tryptophan levels were substantially reduced before treatment in the chronic pain syndrome and increased toward normal during treatment. There was a direct correlation between improvement in amino acid concentration and treatment response. Treatment with amino acid precursors was associated with substantial improvement in chronic back pain, reduction in inflammation, and improvement in back pain correlated with increased amino acid precursors to neurotransmitters in blood.

Effects of Takju intake and moderate exercise training on brain acetylcholinesterase activity and learning ability in rats

Takju is a Korean alcoholic beverage made from rice, and is brewed with the yeast Saccharomyces cerevisiae. This study was conducted to evaluate the effects of exercise training and moderate Takju consumption on learning ability in 6-week old Sprague-Dawley male rats. The rats were treated with exercise and alcohol for 4 weeks in six separate groups as follows: non-exercised control (CC), exercised control (EC), non-exercised consuming ethanol (CA), exercised consuming ethanol (EA), non-exercised consuming Takju (CT), and exercised consuming Takju (ET). An AIN-93M diet was provided ad libitum. Exercise training was performed at a speed of 10 m/min for 15 minutes per day. Ethanol and Takju were administered daily for 6-7 hours to achieve an intake of about 10 ml after 12 hours of deprivation, and, thereafter, the animals were allowed free access to deionized water. A Y-shaped water maze was used from the third week to understand the effects of exercise and alcohol consumption on learning and memory. After sacrifice, brain acetylcholinesterase (AChE) activity was analyzed. Total caloric intake and body weight changes during the experiment were not significantly different among the groups. AChE activity was not significantly different among the groups. The number of errors for position reversal training in the maze was significantly smaller in the EA group than that in the CA and ET groups, and latency times were shorter in the EA group than those in the CC, EC, CT, and ET groups. The latency difference from the first to the fifth day was shortest in the ET group. The exercised groups showed more errors and latency than those of the non-exercised groups on the first day, but the data became equivalent from the second day. The results indicate that moderate exercise can increase memory and learning and that the combination of exercise and Takju ingestion may enhance learning ability.