Hypothalamic clock governs circadian pain.

Chronic pain exhibits circadian rhythms in humans, but the mechanisms underlying such rhythmicity remain unclear. Here, we found daily oscillations in the nociceptive thresholds in a mouse model of neuropathic pain, driven by a rhythmic circuit from the master clock in the hypothalamus to the descending analgesia system. In the daytime (resting phase), higher vasoactive intestinal peptide (VIP) neuronal activity in suprachiasmatic nucleus (SCN