Fig. 2. Antinociception in normal animals and animals with spinal nerve ligation (SNL) from intrathecal clonidine to thermal stimulation in animals treated with intrathecal saline (•) or the muscarinic receptor antagonist atropine (○). There was no difference between saline- and atropine-treated animals in either group. Each symbol represents the mean ± standard error of four to six animals. *P < 0.05 between normal and spinal nerve ligated animals. t  indicates P < 0.05 compared with preclonidine value.