ABSTRACT
Introduction: Caffeine and the selective A2A receptor antagonist SCH58261 both have ergogenic properties, effectively reducing fatigue and enhancing exercise capacity. This study investigates in male Swiss mice the interaction between adenosine A2A receptors and dopamine D2 receptors controlling central fatigue, with a focus on the striatum where these receptors are most abundant. Methods: We employed DPCPX and SCH58261 to antagonize A1 and A2A receptors, caffeine as a non-competitive antagonist for both receptors, and haloperidol as a D2 receptor antagonist; all compounds were tested upon systemic application and caffeine and SCH58261 were also directly applied in the striatum. Behavioral assessments using the open field, grip strength, and treadmill tests allowed estimating the effect of treatments on fatigue. Results and discussion: The results suggested a complex interplay between the dopamine and adenosine systems. While systemic DPCPX had little effect on motor performance or fatigue, the application of either caffeine or SCH58261 was ergogenic, and these effects were attenuated by haloperidol. The intra-striatal administration of caffeine or SCH58261 was also ergogenic, but these effects were unaffected by haloperidol. These findings confirm a role of striatal A2A receptors in the control of central fatigue but suggest that the D2 receptor-mediated control of the ergogenic effects of caffeine and of A2A receptor antagonists might occur outside the striatum. This prompts the need of additional efforts to unveil the role of different brain regions in the control of fatigue.
ABSTRACT
Tissue injuries that affect the skin and/or adjacent tissues and are usually over a bony prominence are called pressure injuries. The prevalence of these dysfunctions remains high, and despite technological advances, there is no consensus on the most appropriate treatment. The objective of this review was to evaluate the efficacy of photobiomodulation (PBM), ultrasound, and high-frequency electrophysical agents in the healing of pressure injuries in adults and the elderly. The search was conducted in the PubMed, Embase, Cochrane Library, Web of Science, and PEDro databases; in clinical trial records, a list of references of the selected articles, as well as through manual search (Google), of the last 5 years in humans in English and Portuguese. Nine thousand and sixty-seven studies were identified, 13 pre-selected, and 6 were included in this systematic review. PBM showed similar efficacy to other technologies indicated in other studies in healing pressure injuries. PBM with red wavelength (660 nm) in stages 2 and 3 pressure injuries effectively promoted healing compared to standard care. It was observed that the use of PBM accelerates tissue repair in pressure injuries; therapeutic ultrasound showed similar efficacy to other electrophysical agents but was effective in reducing the area of pressure injuries when comparing pre- and post-intervention. No clinical studies using the high-frequency electrophysical agent have been described in the last 5 years.