Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jan 2011
Mechanical hypersensitivity, sympathetic sprouting, and glial activation are attenuated by local injection of corticosteroid near the lumbar ganglion in a rat model of neuropathic pain.
Inflammatory responses in the lumbar dorsal root ganglion (DRG) play a key role in pathologic pain states. Systemic administration of a common anti-inflammatory corticosteroid, triamcinolone acetonide (TA), reduces sympathetic sprouting, mechanical pain behavior, spontaneous bursting activity, and cytokine and nerve growth factor production in the DRG. We hypothesized that systemic TA effects are primarily due to local effects on the DRG. ⋯ A single injection of corticosteroid in the vicinity of the axotomized DRG can mimic many effects of systemic TA, mitigating behavioral and cellular abnormalities induced by spinal nerve ligation. This provides a further rationale for the use of localized steroid injections clinically and provides further support for the idea that localized inflammation at the level of the DRG is an important component of the spinal nerve ligation model, commonly classified as neuropathic pain model.
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Reg Anesth Pain Med · Jan 2011
Effect of continuous posttraumatic intrathecal nocistatin on the development of mechanical allodynia.
The neuropeptide nocistatin has a variety of effects on nociception and other central nervous system functions. It has shown to exert diverging effects on nociceptive behavior in various experimental pain models depending on the dose administered. The inhibitory effect of spinal nocistatin on the release of glycine and γ-aminobutyric acid is thought to be responsible for pronociceptive effects, whereas the antinociceptive action of nocistatin can be attributed to diminished glycine-dependent N-methyl-D-aspartate receptor activation. So far, nocistatin has only been investigated in experimental models of already established pain and has been injected as a bolus. ⋯ Because nocistatin has well-documented effects on established pathological pain, it is conceivable that its effect on nociception is only effective when spinal circuitry is pathologically altered.