Accumulating research indicates that melatonin has a major role in pain transmission and has an ultra-sensitizing effect. Dr. Fang Huang and colleagues from Sun Yat-sen University in China for the first time located the distribution of melatonin receptor 1 in the caudal spinal trigeminal nucleus.
Their results, published in the Neural Regeneration Research (Vol. 8, No. 32, 2013), showed that when melatonin receptor 1 expression in the caudal spinal nucleus is significantly reduced, melatonin's regulatory effect on pain is attenuated.
Further study is required to determine whether the decreased melatonin receptor 1 expression in the central caudal trigeminal spinal nucleus can attenuate the analgesic effect of the melatonin/melatonin receptor/nitric oxide pathway.
Orofacial inflammatory pain affects the expression of MT1 and NADPH-d in rat caudal spinal trigeminal nucleus and trigeminal ganglion, Huang F, He HW, Fan WG, Liu YL, Zhou HY, Cheng B, Neural Regen Res. 2013;8(32):2991-3002.
Image credit: Neural Regeneration Research