PTPN1 and Endoplasmic Reticulum Stress: To explore the involvement of ER stress in the analgesic effect of PTP1B‐IN‐1, SNI rats were administered PTP1B‐IN‐1 (1 μg, i.t.)along with the ER stress inducer Tm (20 μg, i.t.)once daily from day 7 to day 11.