Fig. 3. Antinociception in normal animals and animals with spinal nerve ligation (SNL) from intrathecal clonidine to paw pressure stimulation in animals treated with intrathecal saline (•) or the muscarinic receptor antagonist atropine (○). There was no difference between saline and atropine treatment in normal animals, but there was in SNL animals (φP < 0.05 between saline and atropine). Withdrawal threshold was reduced by spinal nerve ligation (*P < 0.05 between normal and spinal nerve ligated animals). Each symbol represents the mean ± standard error of six animals.