Articles: hyperalgesia.
-
Neuropathic pain results from lesions or diseases affecting the somatosensory system. The management of patients with chronic neuropathic pain remains a challenge. Several studies support the crucial role of neuroactive steroids in the modulation of pain. ⋯ The chronic administration of progesterone significantly reduced the behavioral scores of cold- and mechano-allodynia and heat hyperalgesia but single dose of progesterone did not have any effect on behavioral scores of neuropathic pain. Our data indicate that the early chronic administration of progesterone prevents the development of neuropathic pain but its acute injection does not change the expression of neuropathic pain. These results suggest that progesterone could be considered as a new approach for management of neuropathic pain.
-
Inflammation is a major factor shaping outcome during the early, acute phase of traumatic spinal cord injury (SCI). It is known that pro-inflammatory signaling within the injured spinal cord drives pathological alterations in neurosensory processing and shapes functional outcome early after injury. However, it is unclear whether inflammation persists into the chronic phase of injury or shapes sensory processing long after injury. ⋯ We found that 28 d treatment of chronically injured rats with the dual COX/5-LOX inhibitor licofelone elevated levels of endogenous anti-oxidant and anti-inflammatory metabolites within the lesion site. Furthermore, licofelone treatment reduced hypersensitivity of hindpaws to mechanical, but not thermal, stimulation, indicating that mechanical sensitivity is modulated by pro-inflammatory signaling in the chronic phase of injury. Together, these findings provide novel evidence of inflammation and oxidative stress within spinal cord tissue far into the chronic phase of SCI, and demonstrate a role for inflammatory modulation of mechanical sensitivity in the chronic phase of injury.
-
Clinical studies indicate that patients with post-traumatic stress disorder (PTSD) frequently share comorbidity with numerous chronic pain conditions. However, the sustained effects of PTSD-like stress over time on visceral nociception and hyperalgesia have been rarely studied, and the underlying mechanisms of stress-induced modulation of visceral hyperalgesia remain elusive. The purpose of this study was to investigate the characterization of visceral nociception and hyperalgesia over time in rats exposed to PTSD-like stress, and to explore the potential role of protein kinase C gamma (PKCγ) in mediating visceral hyperalgesia following exposure to PTSD-like stress. ⋯ The modified SPS alters visceral sensitivity to CRD, and contributes to the maintenance of visceral hyperalgesia, which is associated with enhanced PKCγ expression in the spinal cord. Functional blockade of the PKCγ receptors attenuates SPS-induced visceral hyperalgesia. Thus, the present study identifies a specific molecular mechanism for visceral hyperalgesia which may pave the way for novel therapeutic strategies for PTSD-like conditions.
-
This study aimed to examine the association of hemiplegic shoulder pain (HSP) with central hypersensitivity through pressure-pain thresholds (PPTs) in healthy, distant tissues. ⋯ The subjects with HSP have lower local and distal PPTs than the subjects without HSP. This study suggests that chronic shoulder pain may be associated with widespread central hypersensitivity, which has been previously found to be associated with other chronic pain syndromes. This further understanding can then help develop better treatment options for those with this HSP.
-
Dynamic mechanical allodynia is traditionally induced by manual brushing of the skin. Brushing force and speed have been shown to influence the intensity of brush-evoked pain. There are still limited data available with respect to the optimal stroke number, length, force, angle and speed. Therefore, an automated brushing device (ABD) was developed, for which brushing angle and speed could be controlled to enable quantitative assessment of dynamic mechanical allodynia. ⋯ A controlled, automatic brushing method can be used for quantitative investigations of allodynic reactions, and is more reliable for quantitative assessment of dynamic mechanical allodynia compared with traditional manual brushing.