Dose–response curves to i.t. N/OFQ (0.1–10 nmol, panel A) and PWT2-N/OFQ (2.5–250 pmol, panel B) in mice with neuropathic pain. N/OFQ and PWT2-N/OFQ N/OFQ induced a dose-dependent (F(3,28) = 24.8; P < 0.05; F(3,28) = 52.5; P < 0.05) and time-dependent (F(4,112) = 42; P < 0.05; F(7,196) = 36.8; P < 0.05) anti-allodynic effect. Each data point represents mean ± SEM (n = 8). *P < 0.05, significantly different from vehicle controls, from the first to the corresponding time point. Note that the zero-time point is a pretest value (see Methods).