Figure 3.

Fb-A_2AR KO and st-A_2AR KO mice show normal spatial recognition memory in the Y-maze. To evaluate memory for distant spatial cues, mice were first allowed 5 min to explore the start and familiar arms of the maze (sample phase) and then returned to the maze after a delay period (2 min, 30 min, 3.5 h, and then 1 d) and given 3 min to explore these same two arms plus an additional, novel arm (test phase). Preference for the novel arm, expressed as the percentage of time spent in the novel arm [(time in novel arm/time in all arms) × 100%], during each test phase was used to index spatial recognition memory. (A) Fb-A_2AR KO and fb-WT mice showed a similar preference for the novel arm, which progressively weakened at a comparable rate with increasing retention demands. (B) St-A_2AR KO and st-WT mice also showed a strong and comparable preference for the novel arm that gradually declined at a similar rate toward chance performance upon increasing the delay interval. Values depicted are mean ± SEM. Chance level = 33.33%, dashed line.