ADORA2A and myasthenia gravis: Like that observed with the toxin-induced MG animal model [7], data presented in this study indicates that endogenous adenosine generated in myasthenic motor endplates during repetitive nerve firing (Figure 5(a)) may be insufficient to preserve transmitter release during repetitive neuronal firing via tonic activation of presynaptic facilitatory A2AR (Figure 4(c)).