Figure 4: Morphine-induced tolerance in the presence of methoctramine, an M2 cholinergic receptor antagonist and LASSBio-981. A) Latency in response to thermal stimulation in rats submitted to SNL. LASSBio-981 (10 mg/kg) was administered daily by gavage during 7 days after establishment of morphine tolerance (16 days infusion). B) After treatment with LASSBio-981, methoctramine (10 μg) was administered by intrathecal route. Data are represented as mean ± SEM (n=4).*P<0.05 versus day 0; versus day 7; †P<0.05 versus time 0.