Previous studies have shown presynaptic modulation of adenosine A 2 A receptors for GABAergic synaptic transmission in the globus pallidus (GP). The pallidal A 2 A receptor-mediated modulation is caused by an action on the terminals of striatopallidal medium spiny neurons (MSNs) and/or axon collaterals of GP neurons. Herein, we examined the precise target neurons of the A 2 A receptor-mediated modulation. Activation of A 2 A receptors enhanced striatopallidal GABAergic transmission onto GP neurons, accompanied by a reduction in the paired-pulse facilitation, indicating the presynaptic contribution of A 2 A receptors at terminals of striatopallidal MSNs in the GP. Besides, no A 2 A receptor mRNA was detected in GP neurons by single-cell reverse transcription-polymerase chain reaction analysis, implying no contribution of axon collaterals of GP neurons to the A 2 A receptor regulation. These results demonstrate that the target neurons of adenosinergic modulation via A 2 A receptors in the GP are the striatopallidal MSNs.