RO-275 (compound 29), recognized for its potency and selectivity, acts as an orally active HCN1 inhibitor, exhibiting IC 50 values of 0.046 µM for HCN1, 14.3 µM for HCN2, 4.6 µM for HCN3, and 13.9 µM for HCN4. Notably, RO-275 enhances working memory, suggesting its research utility for cognitive impairments associated with brain disorders [1] [2].

RO-275, administered intraperitoneally at doses of 3, 10, or 30 mg/kg, enhances working memory performance in male Sprague Dawley rats. At 10 mg/kg, it tended to improve results in a touchscreen task with a 6-second delay. At 30 mg/kg, it significantly reduced incorrect trials in a trial-unique, delayed non-matching-to-location (TUNL) assessment.