Inhibition of Tumor-Derived C-C Motif Chemokine Ligand 2 Expression Attenuates Tactile Allodynia in NCTC 2472 Fibrosarcoma-Inoculated Mice.

Neuropathic pain associated with cancers is caused by tumor growth compressing and damaging nerves, which would also be enhanced by inflammatory factors through sensitizing nociceptor neurons. A troublesome hallmark symptom of neuropathic pain is hypersensitivity to innocuous stimuli, a condition known as "tactile allodynia", which is often refractory to NSAIDs and opioids. The involvement of chemokine CCL2 (monocyte chemoattractant protein-1) in cancer-evoked neuropathic pain is well established, but opinions remain divided as to whether CCL2 is involved in the production of tactile allodynia with tumor growth.

Glucocorticoid regulation of ATP release from spinal astrocytes underlies diurnal exacerbation of neuropathic mechanical allodynia.

Diurnal variations in pain hypersensitivity are common in chronic pain disorders, but the underlying mechanisms are enigmatic. Here, we report that mechanical pain hypersensitivity in sciatic nerve-injured mice shows pronounced diurnal alterations, which critically depend on diurnal variations in glucocorticoids from the adrenal glands. Diurnal enhancement of pain hypersensitivity is mediated by glucocorticoid-induced enhancement of the extracellular release of ATP in the spinal cord, which stimulates purinergic receptors on microglia in the dorsal horn.

Dosing time-dependent changes in the analgesic effect of pregabalin on diabetic neuropathy in mice.

Patients with diabetes often develop peripheral nerve complications, including numbness and pain in the extremities. Diabetes-induced peripheral neuropathic pain is characterized by hypersensitivity to innocuous stimuli, known as tactile allodynia. Pregabalin (PGN) is currently used to treat diabetes-induced peripheral neuropathy and alleviates allodynia.