Tuning adenosine A1 and A2A receptors activation mediates l-citrulline-induced inhibition of [3H]-acetylcholine release depending on nerve stimulation pattern

Data indicate that NOS-derived l-citrulline negatively modulates [3H]-ACh release by increasing adenosine outflow channelling to A1 and A2A receptors activation depending on the stimulus paradigm. While adenosine acts predominantly at inhibitory A1 receptors during 5 Hz-trains, inhibition of ACh release by l-citrulline at 50 Hz-bursts depends on the interplay between adenosine A2A and muscarinic M2 receptors.