Adenosine, a sleep-associated neuromodulator, is crucial in various physiological and pathological processes. Previous studies have demonstrated that sleep deprivation (SD) alters striatal neuronal activity. In this study, we used in vitro electrophysiological recordings to investigate the effects of 20 h of SD on the neuronal excitability of mouse dorsal striatal medium spiny neurons (MSNs). Our findings revealed that SD resulted in altered action potential (AP) discharge properties and reduced neuronal excitability compared to the control group. Importantly, these changes were partially offset by the prophylactic injection of the A2A receptor (A2AR) antagonist SCH58261. Additionally, 20 h of SD caused a decrease in the amplitude and an increase in the interval of spontaneous excitatory postsynaptic currents (sEPSCs) compared to control. However, the prophylactic injection of the A2AR antagonism shortened the sEPSC interval, while the A1 receptor (A1R) antagonist DPCPX not only shortened the interval but also further reduced the amplitude of sEPSCs. Thus, it can be concluded that SCH58261 effectively prevents the reduction in excitability of striatal MSNs in mice following 20 h of sleep deprivation, whereas DPCPX does not.