No abstract available.
Hyperalgesia

No abstract available.
Hyperalgesia

No abstract available.
Electroacupuncture ; Hyperalgesia

BACKGROUND: Neuropathic pain resulting from diverse causes is a chronic condition for which effective treatment is lacking. The goal of this study was to test whether dexamethasone exerts a preemptive analgesic effect with bupivacaine when injected perineurally in the spared nerve injury model. METHODS: Fifty rats were randomly divided into five groups. Group 1 (control) was ligated but received no drugs. Group 2 was perineurally infiltrated (tibial and common peroneal nerves) with 0.4% bupivacaine (0.2 ml) and dexamethasone (0.8 mg) 10 minutes before surgery. Group 3 was infiltrated with 0.4% bupivacaine (0.2 ml) and dexamethasone (0.8 mg) after surgery. Group 4 was infiltrated with normal saline (0.2 ml) and dexamethasone (0.8 mg) 10 minutes before surgery. Group 5 was infiltrated with only 0.4% bupivacaine (0.2 ml) before surgery. Rat paw withdrawal thresholds were measured using the von Frey hair test before surgery as a baseline measurement and on postoperative days 3, 6, 9, 12, 15, 18 and 21. RESULTS: In the group injected preoperatively with dexamethasone and bupivacaine, mechanical allodynia did not develop and mechanical threshold forces were significantly different compared with other groups, especially between postoperative days 3 and 9 (P < 0.05). CONCLUSIONS: In conclusion, preoperative infiltration of both dexamethasone and bupivacaine showed a significantly better analgesic effect than did infiltration of bupivacaine or dexamethasone alone in the spared nerve injury model, especially early on after surgery.
Animals ; Bupivacaine ; Dexamethasone ; Hair ; Hyperalgesia ; Neuralgia ; Rats

BACKGROUND: Gabapentin is widely used for the relief of neuropathic pain. But, there is no study of gabapentin in relation to traumatic neuropathic pain. The aim of this study is to assess the efficacy and effectiveness of gabapentin for the various clinical symptoms of traumatic neuropathic pain MATERIALS AND METHODS: 50 patients with traumatic nerve injury were assigned to receive gabapentin, titrated to 900 mg/day over 9 days, followed by further increases to a maximum of 2400 mg/day. Continuous pain, paroxysmal pain, allodynia and thermal evoked pain were measured in mean daily pain scores, based on the 11-point Likert scale. The primary efficacy parameter was compared from the baseline to the final study week. RESULTS: Over the 4.5 week study, this pain score decreased by 2.6 points in the continuous pain, 3.6 points in the paroxysmal pain, 3.1 points in the allodynia, and 2.5 points in the thermal evoked pain. The percentage of patients with over 50% improvement in pain scores was 33% in the continuous pain, 67% in the paroxysmal pain, 53% in the allodynia and 36% in the thermal evoked pain. There was no significant correlation between the effect of gabapentin and the time difference of the onset of symptoms and start of medication. CONCLUSIONS: This study shows that gabapentin reduced neuropathic pain in patients with traumatic peripheral nerve injury. Among the various characteristics of neuropathic pain, the reduction of paroxysmal pain and allodynia was greatest.
Humans ; Hyperalgesia ; Neuralgia ; Peripheral Nerve Injuries

BACKGROUND: Soluble epoxide hydrolase (sEH) is an enzyme that converts epoxyeicosatrienoic acid (EET) into the anti-inflammatory dihydroxyeicosatrienoic acids (DHET). Inhibition of sEH by the potent soluble epoxide hydrolase inhibitor (sEHI) decreases inflammation by increasing EET. The K/BxN serum transfer mouse model of arthritis displays an initial inflammation and an associated tactile allodynia that continues on following the resolution of inflammation. METHODS: We undertook the following studies: i) Using the K/BxN mouse model, we examined effects on allodynia during the early inflammatory phase of administration of sEHI 3 mg/kg and/or diclofenac (DFC) 10 mg/kg. ii) In the late inflammatory phase, we administered sEHI (3, 10, or 30 mg/kg); DFC 10 mg/kg; gabapentin 100 mg/kg. iii) Using the conditioned place preference (CPP) we examined the synergism between sEHI and DFC in the K/BxN mouse using the CPP paradigm. The drug was administered intraperitoneally and the allodynia was measured with the von Frey test. RESULTS: In the early phase, both sEHI and DFC displayed an antiallodynic action. In the late phase, sEHI, and gabapentin but not DFC were effective in reversing the allodynia. Comparable results were observed with the CPP. CONCLUSIONS: This study demonstrates that sEHI reduces mechanical allodynia in both the early and the late inflammatory K/BxN mouse model of arthritis. The sEHI target thus addresses the hyperalgesia arising from inflammation as well as the post-inflammatory phase that has been said to reflect neuropathic-like states, thus presenting alternatives to the limited efficacy of arthritis drugs in use.
Animals ; Arthritis* ; Diclofenac ; Hyperalgesia ; Inflammation ; Mice*

No abstract available.
Animals ; Curcumin* ; Hyperalgesia* ; Ligation* ; Rats* ; Spinal Nerves*

BACKGROUND: The lidocaine patch has been effectively used as a first-line therapy to treat neuropathic pain such as postherpetic neuralgia (PHN). OBJECTIVE: To evaluate the safety and efficacy of the topical piroxicam patch as a treatment option for the treatment of PHN. METHODS: Eighteen patients completed a 3-session study, applying three different patches (lidocaine, piroxicam and control) in random order. A maximum of three patches were applied to the most painful area for three consecutive days (12 hours on followed by 12 hours off). Each session was conducted at least seven days apart. The changes in visual analog scale (VAS) scores based pain intensity, quality of sleep and adverse effects were recorded. RESULTS: When compared to the control, both the lidocaine and piroxicam patches significantly reduced the mean VAS scores of pain intensity of all different types. However, the lidocaine patch was better at reducing allodynia, whereas the piroxicam patch was more effective for dull pain. The lidocaine patch worked faster than the piroxicam patch for the response to overall pain relief. CONCLUSION: The results of this study suggest the use of the piroxicam patch for dull pain and in patients where the lidocaine patch is contraindicated.
Humans ; Hyperalgesia ; Lidocaine ; Neuralgia ; Neuralgia, Postherpetic ; Piroxicam

BACKGROUND: Clonidine is an alpha2-adrenergic drug used for analgesic effect, reducing sympathetic stimulation and anesthetic requirement. We examined the analgesic effect of clonidine on incisional pain after its intrathecal administration using a rat postincisional model. METHODS: After an intrathecal (IT) catheter insertion in 20 Spraw Dawley rats, they were divided into two groups; one group (Group S, n = 10) received a saline 20microl injection through an IT catheter, and another (Group C, n = 10) received clonidine 20microgram in 10microl volume followed by another 10microl of saline for washing the catheter. The measurements of the threshold of tactile allodynia (TTA) were performed at 20, 40, 60, 80, 120, 180 and 240 mins after the IT injection. Additionally, 1, 2 and 3 days after the first IT injection, IT injection and the measurements of TTA of pre- and post-injection were repeated. The measurements of TTA were performed in both areas, 5 mm (N-area) and 10 mm (R-area) away from incision by using von Frey hair and up-down method. RESULTS: TTA (N-area) and TTA (R-area) during 4 hours after IT injection in Group C were greater than those in Group S (P< 0.05). TTA (N-area) of post-injection 2 and 3 days after the first IT injection were greater than those of pre-injection in Group C (P< 0.05), and TTA (R-area) after the IT injection 1, 2 and 3 days after the first IT injection were greater than those of pre-injection in Group C (P< 0.05). CONCLUSIONS: A single IT injection of clonidine 20microgram had analgesic effects lasting more than 4 hours in the rat postincisional model. Additional IT clonidine could show antiallodynic effects during three days after the first IT clonidine.
Animals ; Catheters ; Clonidine* ; Hair ; Hyperalgesia ; Rats*

No abstract available.
Animals ; Hyperalgesia ; Microglia ; Rats ; Up-Regulation