"Functional development of nociceptive spino-bulbo-spinal pathways in postnatal rats"
Prof S Hunt & Prof M Fitzgerald
Department of Anatomy Funds
Description of Project:
Neurokinin-1 (NK1) receptor expressing neurons in lamina I of the spinal dorsal horn contribute to a spino-bulbo-spinal loop that transmits nociceptive signals to the brain and modulates pain sensitivity (Suzuki et al. 2002). We investigated the anatomical and functional development of this circuit in postnatal rats. We have found that the ascending and descending parts of the circuit are mostly present and functional at birth but the levels of NK1 receptors and serotonin mature late in the postnatal period. Selective ablation of the NK1 pathway with a receptor ligand-conjugated toxin in newborn rats led to mild long-term changes in pain sensitivity. We have also developed a simple method of studying affective-motivational aspects of pain. Place-conditioning with a painful injection in the hindpaw of adult rats led to learning and avoidance of an environment with pain-predictive cues.
Suzuki, R., Morcuende, S., Webber, M., Hunt, S. P., & Dickenson, A. H. 2002, "Superficial NK1-expressing neurons control spinal excitability through activation of descending pathways", Nature Neuroscience, vol. 5, no. 12, pp. 1319-1326.