Spinal nerve injury activates prostaglandin synthesis in the spinal cord that contributes to early maintenance of tactile allodynia
| Autor: | Melissa Haley, Pamela Carter, Christopher W. Loomis, Michael P. Hefferan |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Male
medicine.medical_specialty Microdialysis Central nervous system Prostaglandin Ibuprofen Dinoprostone Rats Sprague-Dawley chemistry.chemical_compound Physical Stimulation Internal medicine medicine Animals Cyclooxygenase Inhibitors Ligation Sulfonamides Lumbar Vertebrae Cyclooxygenase 2 Inhibitors business.industry Membrane Proteins Spinal cord medicine.disease Rats Isoenzymes Spinal Nerves Anesthesiology and Pain Medicine medicine.anatomical_structure Allodynia Peripheral neuropathy Endocrinology Spinal Cord Neurology chemistry Cyclooxygenase 2 Prostaglandin-Endoperoxide Synthases Touch Anesthesia Spinal nerve Cyclooxygenase 1 Neuralgia Pyrazoles Neurology (clinical) medicine.symptom business |
| Zdroj: | Pain. 101:139-147 |
| ISSN: | 0304-3959 |
| Popis: | To determine if spinal prostaglandins (PG) contribute to tactile allodynia, male, Sprague-Dawley rats were fitted with either intrathecal (i.t.) microdialysis or drug delivery catheters 3 days before tight ligation of the left lumber 5/6 spinal nerves. Paw withdrawal thresholds (PWT) were determined using von Frey filaments. Ligated rats developed tactile allodynia within 24h, as evidenced by a decrease in PWT in the affected hindpaw (4 g vs.15 g control). Sham-operated controls were unchanged from baseline (15 g). Allodynia was also characterized by a significant increase in the evoked release of PGE(2). Thus, brushing the plantar surface of the affected hindpaw with a cotton-tipped applicator, 5 days postligation, increased the [PGE(2)](dialysate) to 199+/-34% of the prestimulus control period. In contrast, brushing had no detectable effect on release before surgery or in sham-operated animals. Basal release (no brushing) was similar before and after surgery (sham-operated and ligated rats). In a separate group of rats and beginning 2 days after ligation, the acute i.t. injection of S(+)-ibuprofen, SC-51322, SC-236, or SC-560 significantly reversed allodynia (maximum effect=69+/-9, 66+/-6, 57+/-4, 20+/-5%, respectively). R(-)-ibuprofen or vehicle were without effect. The results of this study suggest that: (a). spinal PG synthesis and allodynia-like behaviour are triggered by normally innocuous brushing after spinal nerve ligation; (b). pharmacological disruption of this cascade significantly reverses allodynia; (c). COX-2 is the relevant isozyme; and (d). the PG effect is mediated by spinal EP receptors. |
| Databáze: | OpenAIRE |
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