Descending facilitation from rostral ventromedial medulla mu opioid receptor-expressing neurons is necessary for maintenance of sensory and affective dimensions of chronic neuropathic pain

Dogrul BN, Dogrul BN, Machado Kopruszinski C, Dolatyari Eslami M, Watanabe M, Luo S, Moreira de Souza LH, Vizin RL, Yue X, Palmiter RD, Navratilova E, Porreca F (2025) Descending facilitation from rostral ventromedial medulla mu opioid receptor-expressing neurons is necessary for maintenance of sensory and affective dimensions of chronic neuropathic pain. Pain 166(1):153-159. doi: 10.1097/j.pain.0000000000003360 PMID: 39058958

Objective: To determine whether rostral ventromedial medulla (RVM) mu opioid receptor (MOR)–expressing neurons are required for the expression and maintenance of established neuropathic pain.

Summary: Using chemogenetic silencing of MOR-expressing neurons, the study showed that inhibition of RVM-MOR cells reversibly reduces tactile allodynia and the affective component of neuropathic pain, demonstrating that descending facilitation from these neurons sustains chronic pain. The authors reference earlier findings using Dermorphin-SAP to confirm that complete ablation of MOR-expressing RVM neurons prevents neuropathic pain development without affecting acute surgical pain.

Usage: Dermorphin-SAP (IT-12) was referenced from prior studies as a method for selective ablation of MOR-expressing RVM neurons that prevented mechanical allodynia following spinal nerve ligation.

Related Products: Dermorphin-SAP / MOR-SAP (Cat. #IT-12)

See Also:

• Porreca F et al. Inhibition of neuropathic pain by selective ablation of brainstem medullary cells expressing the µ-opioid receptor. J Neurosci 21(14):5281-5288, 2001.