Starowicz Katarzyna, Bilecki Wiktor, Sieja Agnieszka, Przewlocka Barbara, Przewlocki Ryszard
Institute of Pharmacology, Polish Academy of Sciences, Department of Molecular Neuropharmacology, 12 Smetna Street, 31-343 Cracow, Poland.
Neurosci Lett. 2004 Mar 25;358(2):79-82. doi: 10.1016/j.neulet.2003.12.096.
Recent reports have demonstrated effectiveness of melanocortin antagonists as potent analgesics, and have suggested that the spinal melanocortin 4 receptor (MC4-R) mediates their effects on pain transmission. These findings prompted us to investigate the changes in MC4-R mRNA level in the spinal cord and dorsal root ganglia (DRG) of neuropathic animals at different time points after sciatic nerve injury by quantitative real-time PCR. The spinal MC4-R mRNA level was not affected by sciatic nerve injury. In contrast, down-regulation of MC4-R mRNA in DRG developed 2 weeks after the injury and was parallel with the attenuated effectiveness of MC4-R ligands in neuropathic animals. The MC4-R adaptation in DRG observed in neuropathic rats indicates their important role in presynaptic modulation of activity of the primary afferents in neuropathic pain.
