The effects of hibernation on the contractile and biochemical properties of skeletal muscles in the thirteen-lined ground squirrel, Ictidomys tridecemlineatus

Hibernation is a crucial strategy of winter survival used by many mammals. During hibernation, thirteen-lined ground squirrels, Ictidomys tridecemlineatus, cycle through a series of torpor bouts, each lasting more than a week, during which the animals are largely immobile. Previous hibernation studies have demonstrated that such natural models of skeletal muscle disuse cause limited or no change in either skeletal muscle size or contractile performance. However, work loop analysis of skeletal muscle, which provides a realistic assessment of in vivo power output, has not previously been undertaken in mammals that undergo prolonged torpor during hibernation. In the present study, our aim was to assess the effects of 3 months of hibernation on contractile performance (using the work loop technique) and several biochemical properties that may affect performance. There was no significant difference in soleus muscle power output-cycle frequency curves between winter (torpid) and summer (active) animals. Total antioxidant capacity of gastrocnemius muscle was 156% higher in torpid than in summer animals, suggesting one potential mechanism for maintenance of acute muscle performance. Soleus muscle fatigue resistance was significantly lower in torpid than in summer animals. Gastrocnemius muscle glycogen content was unchanged. However, state 3 and state 4 mitochondrial respiration rates were significantly suppressed, by 59% and 44%, respectively, in mixed hindlimb skeletal muscle from torpid animals compared with summer controls. These findings in hindlimb skeletal muscles suggest that, although maximal contractile power output is maintained in torpor, there is both suppression of ATP production capacity and reduced fatigue resistance

Effect of dietary manganese supplementation on Mn, Fe, Cu, Zn, Mg, and Ca contents in rat's tissues

The aim of this paper was determination of Mn, Fe, Cu, Zn, Mg, and Ca concentrations in different organs of rats supplemented with manganese-proteinate for 43 days. Inorganic forms are usually used as dietary supplements giving free metal ions in intestine for absorption. Different dietary and metabolic factors influence metal ions' absorption and transport. Over the past ten years interest in using minerals bounded to protein ligands has increased because of numerous supposed advantages of organic metal forms. Long-termed intake of moderate doses of supplemental manganese-proteinate increased Mn concentrations in kidney, muscle and skin, but not in liver. At the same time supplementation with Mn significantly influenced levels of Zn and Mg in kidney, Ca in skin and lowered Fe in skin

Low-Frequency Repetitive Transcranial Magnetic Stimulation in the Right Prefrontal Cortex Combined With Partial Sleep Deprivation in Treatment-Resistant Depression A Randomized Sham-Controlled Trial

Introduction: Sham-controlled low-frequency repetitive transcranial magnetic stimulation (rTMS) was used in patients with pharmacoresistant major depression as an added treatment along with partial sleep deprivation (PSD). In addition, the potential predictive role of brain-derived neurotrophic factor genetic polymorphism on treatment response was analyzed. Methods: We recruited 19 female patients (48.3 +/- 8.6 years old) with treatment-resistant unipolar major depression (Hamilton Depression Rating Scale [HDRS] score gt = 20) who were on a stable antidepressant treatment. They received either 1-Hz rTMS or sham stimulation over the right dorsolateral prefrontal cortex (intensity of 110% of the threshold; 3000 stimuli per protocol; and 10 daily sessions). Additionally, PSD was applied once per week during the treatment. The patients were evaluated (HDRS and Clinical Global Impression Scale) by a blind rater at baseline (B) and after 2 and 3 weeks (W2 and W3) of treatment for short-term outcome. Long-term evaluations were performed after 12 (W12) and 24 weeks (W24) for patients who received active stimulation. Results: Eleven patients in the active group showed a significant HDRS score reduction from 30.09 +/- 3.53 (B) to 16.73 +/- 5.71 (W3) compared to the lack of therapeutic response in the sham-treated patients. The long-term follow-up for the active group included 64% of the responders at W12 and 55% at W24. Full remission (HDRS lt = 10) was achieved in 5 of 11 patients. Four of these 5 patients with long-term sustained remission expressed the Val66Val genotype. Conclusion: Our study suggests a clinically relevant response, persisting for up to 6 months, from 1-Hz rTMS over the right dorsolateral prefrontal cortex and PSD in patients with pharmacoresistant major depression. The brain-derived neurotrophic factor Val66Val homozygous genotype may be related to a better treatment outcome