S1PR1 and memory impairment: To determine the functional interaction between S1PR1 and ITGA2 in regulating chronic pain-related memory impairment, a recombinant adeno-associated virus 2/9 (AAV2/9) expressing a small hairpin RNA targeting Itga2 was generated (rAAV-CaMKIIa-EGFP-5′miR-30a-shRNA (Itga2)-3′-miR30a-WPREs, the sequence of shRNA referred to Supplementary file 1a).