PVNCRF Neurons Regulate Migraine-Like Allodynia by Activating CRFR2 on Spinal Trigeminal Caudalis Glutamatergic Neurons.

Migraine is a prevalent and debilitating neurological disorder with poorly understood neural mechanisms. Here, we characterize a hypothalamic-trigeminal pathway involved in the regulation of migraine-like allodynia. Using a combination of monosynaptic circuit, fiber photometry-based calcium imaging, and behavioral assays in a nitroglycerin (NTG)-induced murine model, we observed hyperactivity in corticotropin-releasing factor (CRF)-expressing neurons within the hypothalamic paraventricular nucleus (PVN). Activation or inhibition of PVNCRF neurons mimicked or blocked migraine-like allodynia, respectively. These PVNCRF neurons modulated migraine-like allodynia by exciting glutamatergic neurons in the spinal trigeminal nucleus caudalis (SP5C). Furthermore, employing a CRF neurotransmitter fluorescent sensor, neuropharmacology, and electrophysiological recordings, we revealed that PVNCRF neurons excessively release CRF neuropeptides onto SP5CGlu neurons during migraine-like conditions. This led to hyperactivation of corticotropin-releasing factor receptor type 2 (CRFR2), but not type 1 (CRFR1), resulting in hyperalgesia. Blockade of CRFR2 within the SP5C significantly alleviated migraine-like allodynia. Complementing these findings, clinical functional magnetic resonance imaging (fMRI) of migraine patients indicated structural and functional alterations in PVN and SP5C regions associated with this pathway. Collectively, our results uncover a previously unappreciated PVNCRF-SP5CGlu pathway in migraine-like allodynia, providing novel insights into the neurobiology of migraine and identifying potential therapeutic targets.