Adenosine A2B and A3 receptor location at the mouse neuromuscular junction

To date, four subtypes of adenosine receptors have been cloned (A1R, A2AR, A2BR, and A3R). In a previous study we used confocal immunocytochemistry to identify A1R and A2AR receptors at mouse neuromuscular junctions (NMJs). The data shows that these receptors are localized differently in the three cells (muscle, nerve and glia) that configure the NMJs. A1R localizes in the terminal teloglial Schwann cell and nerve terminal, whereas A2AR localizes in the postsynaptic muscle and in the axon and nerve terminal. Here, we use Western blotting to investigate the presence of A2BR and A3R receptors in striated muscle and immunohistochemistry to localize them in the three cells of the adult neuromuscular synapse. The data show that A2BR and A3R receptors are present in the nerve terminal and muscle cells at the NMJs. Neither A2BR nor A3R receptors are localized in the Schwann cells. Thus, the four subtypes of adenosine receptors are present in the motor endings. The presence of these receptors in the neuromuscular synapse allows the receptors to be involved in the modulation of transmitter release.