Figure 2
From: Inter-strain differences of serotonergic inhibitory pain control in inbred mice
Serotonin afferents in the spinal cord and effects of serotonin depletion. A Immunofluorescent analysis of serotonin in the L4/5 dorsal horn of the spinal cord seven days after sectioning of the dorsal roots L4 and L5 (Rhizotomy) and 7 days after thoracic transection of descending fibers (dorsolateral corticospinal tract) with tyrosine hydroxylase (TH) counter-staining. Scale bar: 50 μm. The insert shows the quantitative pixel analysis of 5-HT immunoreactive fibers. B and C Mechanical and cold nociception in the SNI model following depletion of serotonin in the spinal cord and midbrain. Serotonin depletion was achieved by intrathecal continuous osmotic pump driven infusion of para-chlorophenylalanine (pCPA), an inhibitor of tryptophan hydroxylases through a spinal i.t. catheter. Control animals received vehicle infusions. n = 8 per group. Comparison of AUCs revealed that pCPA-mediated serotonin depletion caused a significant aggravation of nociceptive hypersensitivity after nerve injury.