Neuronal adenosine A2A receptors signal ergogenic effects of caffeine

Abstract

AbstractErgogenic aid is a substance or method used for enhancing exercise and sports performance. Caffeine is the most used ergogenic aid for athletes, but the mechanisms are still unknown. Forty-two adult female (19±0.6 g) and 40 male mice (24±0.4 g) from a global and forebrain A2AR knockout and colony (FMUC, University of Coimbra) underwent an open field and ergospirometry exercise test. Caffeine (15 mg/kg, i.p.) and SCH 58261 (1 mg/kg, i.p.) were administered 15 minutes before the animals ran to exhaustion. We also evaluate the estrous cycle and infrared temperature (rest and recovery). Caffeine was psychostimulant in wild type females and males, but we observed this expected effect of SCH-58261 only in males. Caffeine and SCH-58261 were also ergogenic for wild type animals, that is, they increased running power and maximal O2 consumption (O2max). The psychostimulant and ergogenic effects of caffeine and SCH-58261 disappeared in A2AR knockout females (global) and males (forebrain). The estrous cycle did not influence any evaluated parameters, as well as exercise-induced hyperthermia was similar between savages and knockouts. Our results suggest that the neuronal A2AR receptors signal the ergogenic effects of caffeine in female and male mice.