Acute melatonin administration improves exercise tolerance and the metabolic recovery after exhaustive effort

Abstract

The present study investigated the effects of acute melatonin administration on the biomarkers of energy substrates, GLUT4, and FAT/CD36 of skeletal muscle and its performance in rats subjected to exhaustive swimming exercise at an intensity corresponding to the maximal aerobic capacity (tlim). The incremental test was performed to individually determine the exercise intensity prescription and 48 h after, the animals received melatonin (10 mg·kg−1) or vehicles 30 min prior to tlim. Afterwards, the animals were euthanized 1 or 3 h after the exhaustion for blood and muscles storage. The experiment 1 found that melatonin increased the content of glycogen and GLUT4 in skeletal muscles of the animals that were euthanized 1 (p < 0.05; 22.33% and 41.87%) and 3 h (p < 0.05; 37.62% and 57.87%) after the last procedures. In experiment 2, melatonin enhanced the tlim (p = 0.01; 49.42%), the glycogen content (p < 0.05; 40.03%), GLUT4 and FAT/CD36 in exercised skeletal muscles (F = 26.83 and F = 25.28, p < 0.01). In summary, melatonin increased energy substrate availability prior to exercise, improved the exercise tolerance, and accelerated the recovery of muscle energy substrates after the tlim, possibly through GLUT4 and FAT/CD36.

Melatonin Potentiates Exercise-Induced Increases in Skeletal Muscle PGC-1α and Optimizes Glycogen Replenishment

“…Thereby, melatonin seems to optimize the response to exercise since training adaptations reflect the accumulation of beneficial physiological functions produced from single bouts of exercise ( Park et al, 2021 ). Despite the positive results of this study, there are still some limitations that must be addressed: 1) We only focused on the master regulator of the mitochondrial biogenesis and its relationship with NRF-1; however, evaluating other proteins involved in the mitochondrial biogenesis process as well as the PGC-1 α downstream signals could provide additional information on the mechanism of action of melatonin; 2) we chose the dosage of 10 mg/kg due to the effects of melatonin on time to exhaustion ( t lim), as previously reported by our research group ( Beck et al, 2015A ; Beck et al, 2016 ; Faria et al, 2021 ); nonetheless, another concentration of melatonin should be tested to achieve a similar effect with lower dosage. Therefore, our findings make it clear that future studies must be conducted in order to deepen the understanding of the importance of melatonin from a physiological point of view.…”

“…As albino animals are easily affected by phototoxic retinopathy ( ARRP, 2007 ; Castelhano-Carlos and Baumans, 2009 ), a stressful condition capable of generating undesirable interference in experiments, especially those involved with melatonin and circadian rhythm, incandescent lamps (Philips, model Soft, 100 W, 2700 K; 565–590 nm; 60 lux, measured by a lux meter) were used during the 10-hour light cycle. To carry out experimental interventions with the rats during the dark cycle (nighttime: 4:00 p.m. to 6:00 a.m.), reflectors were installed around a red filter (ROSCO, model # fire19; > 600 nm; < 15 lux) ( Beck and Gobatto, 2013 ; Beck et al, 2015B ; Beck et al, 2016 ; Faria et al, 2021 ). Such a luminous scenario makes it possible to prevent the relevant influence of light on the activity of N-acetyltransferase in the pineal gland ( Sun et al, 1993 ), an extremely important enzyme for melatonin biosynthesis.…”

“…Melatonin (Sigma Aldrich Chemical Corporation; St Louis, MO, United States; M-5250, > 98%) was dissolved in ethanol (< 0.1%) and diluted in saline (0.9% NaCl) for administration at 10 mg/kg ( Beck et al, 2015A ; Beck et al, 2016 ; Faria et al, 2021 ). The preparation was performed prior to its use and stored in an amber bottle wrapped in aluminum foil.…”

“…Substantial evidence has confirmed the regulatory role of melatonin in circadian and seasonal rhythms ( Reiter et al, 2010 ; Brzezinski et al, 2021 ; Pevet et al, 2021 ; Hardeland, 2022 ), antioxidant ( Rodriguez et al al, 2004 ; Manchester et al, 2015 ; Reiter et al, 2016 ; Ortiz-Franco et al, 2017 ; Galano et al, 2018 ; Chitimus et al, 2020 ; Kruk et al, 2021 ) and anti-inflammatory effects ( Mauriz et al, 2013 ) among others. In addition to these benefits, our research group has demonstrated the ergogenic effect of melatonin in the increasing exhaustive aerobic exercise tolerance of nocturnal animals ( Beck et al, 2015A ; Beck et al, 2016 ; Faria et al, 2021 ), whereas the effect of melatonin on metabolic recovery after physical exercise is less reported. Specifically, the role of melatonin in muscle glycogen and triglyceride contents few hours after exercise is not fully understood.…”

Effects of Moderate–Intensity Physical Training on Skeletal Muscle Substrate Transporters and Metabolic Parameters of Ovariectomized Rats

“…The protein expressions of this study were performed by immunofluorescence [ 64 ] and the technique performed according to Faria et al [ 65 ] and Pejon et al [ 66 ]. The skeletal muscle evaluated was the soleus due to the high recruitment during the performance of the swimming exercise [ 32 ].…”