RESUMEN
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.
RESUMEN
RESUMO A associação da sarcopenia com fatores sociodemográficos e de saúde já foi previamente apresentada na literatura. Contudo, pouco se sabe sobre como os fatores ambientais que podem estar relacionados a essa condição. O objetivo do estudo foi avaliar a associação entre a autopercepção do ambiente de vizinhança e a sarcopenia provável em idosos comunitários. Este é um estudo transversal, de base domiciliar com amostra probabilística, que incluiu 306 idosos comunitários de ambos os sexos. O desfecho foi a sarcopenia provável, categorizada com o tempo de realização no teste de sentar e levantar da cadeira >15 segundos, conforme proposto pelo European Working Group on Sarcopenia in Older People. As variáveis preditoras foram avaliadas de acordo com o abbreviated neighborhood environment walkability scale (A-NEWS), que inclui questões relacionadas à infraestrutura e à segurança do bairro, ruas, calçadas e tipos de uso do solo. Foram realizadas análises de regressão logística multivariada. A presença de supermercado/loja de conveniência/mercadinho/armazém, feira livre (OR: 0,45; IC 95%: 0,22-0,91) e ponto de ônibus (OR: 0,23; IC 95%: 0,10-0,50) foram fatores de proteção para a sarcopenia provável. Já o acúmulo de lixo e locais com esgoto a céu aberto próximos à residência (OR: 2,17; IC 95%: 1,16-4,05) foram fatores de risco. Verificou-se associação de comércios locais e pontos de ônibus próximos ao local de residência para proteção contra a sarcopenia provável, enquanto o acúmulo de lixo e locais com esgoto a céu aberto próximos à residência se mostraram fatores de risco para a sarcopenia provável.
RESUMEN La asociación entre sarcopenia y factores sociodemográficos y de salud se ha presentado previamente en la literatura. Sin embargo, es escasa la información sobre cómo los factores ambientales pueden relacionarse con esta condición. El objetivo de este estudio fue evaluar la asociación entre la autopercepción del ambiente exterior y una probable sarcopenia en ancianos institucionalizados. Este es un estudio transversal, de base domiciliaria con muestra probabilística, que incluyó a 306 ancianos institucionalizados de ambos sexos. El resultado fue una probable sarcopenia, categorizada con el tiempo necesario para sentarse y levantarse de una silla >15 segundos según lo propuesto por el Grupo Europeo de Trabajo en Sarcopenia en Personas Mayores. Las variables predictoras se evaluaron según el abbreviated neighborhood environment walkability scale (A-NEWS), que incluye temas relacionados con la infraestructura y seguridad del vecindario, calles, aceras y tipos de uso del suelo. Se realizó análisis de regresión logística multivariante. La presencia de supermercado/tienda de conveniencia/tienda/almacén, ferias (OR: 0,45; IC 95%: 0,22-0,91) y parada de autobús (OR: 0,23; IC 95%: 0,10-0,50) fueron los factores protectores contra una probable sarcopenia. La acumulación de basura y lugares con alcantarillado abierto cerca de la residencia (OR: 2,17; IC 95%: 1,16-4,05) fueron los factores de riesgo. Se encontró que as tiendas locales y paradas de autobús cercanas a la residencia estuvieron relacionadas a la protección contra una probable sarcopenia, mientras que la acumulación de basura y lugares con alcantarillado abierto cerca de la residencia estuvieron relacionados a una probable sarcopenia.
ABSTRACT The association of sarcopenia with sociodemographic and health factors has been previously presented in the literature. However, little is known about how environmental factors may be related to this condition. The study sought to verify the association between self-perception of a built neighborhood characteristics and probable sarcopenia in community-dwelling older adults. This was a cross-sectional study including 306 community-dwelling older adults of both genders. The outcome was probable sarcopenia, categorized with the time taken in the sit to stand test >15 seconds, as proposed by the European Working Group on Sarcopenia in Older People. The predictor variables were assessed using the neighborhood environment walkability scale (A-NEWS), which includes issues related to the infrastructure and security of the neighborhood, streets, sidewalks, and types of land use. Multivariate Logistic Regression analyses were performed. The presence of supermarkets/convenience stores/grocery stores/warehouses, open markets (OR: 0.45; 95%CI: 0.22-0.91) and bus stops (OR: 0.23; 95%CI: 0.10-0.50) were protective factors for probable sarcopenia. However, the accumulation of garbage and/or places with open sewage close to the residence (OR: 2.17; 95%CI: 1.16-4.05) were risk factors. There was a protective association of local businesses and bus stops near the place of residence for probable sarcopenia. However, the accumulation of garbage and/or places with open sewage near the residence proved to be risk factors for probable sarcopenia.