Articles: pain-measurement.
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Comparative Study
Detection and mapping of quantitative trait loci that determine responsiveness of mice to nitrous oxide antinociception.
Exposure to 70% N(2)O evokes a robust antinociceptive effect in C57BL/6 (B6) but not in DBA/2 (D2) inbred mice. This study was conducted to identify quantitative trait loci (QTL) in the mouse genome that might determine responsiveness to N(2)O. Offspring from the F(2) generation bred from B6 and D2 progenitors exhibited a broad range of responsiveness to N(2)O antinociception as determined by the acetic acid-induced abdominal constriction test. ⋯ Combined results revealed two significant QTL that influence responsiveness to nitrous oxide on proximal chromosome 2 and distal chromosome 5, and one suggestive QTL on midchromosome 18. The chromosome 2 QTL was evident only in males. A significant interaction was found between a locus on chromosome 6 and another on chromosome 13 with a substantial effect on N(2)O antinociception.
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Stereotact Funct Neurosurg · Jan 2004
Comparative StudyRecovery of pain control by intensive reprogramming after loss of benefit from motor cortex stimulation for neuropathic pain.
Motor cortex stimulation (MCS) may serve as an adjunct in managing neuropathic pain after other conservative and interventional methods have failed. However, the magnitude and duration of the benefit are highly variable, with a significant percentage of patients losing pain relief over time. We investigated whether intensive reprogramming could recapture the beneficial effects of MCS. ⋯ Intensive reprogramming can recapture the benefit of MCS in patients who have lost pain control. The use of broad dipoles using two contacts rather than one contact of the 1 x 4 electrode array improved the ability to recapture beneficial stimulation. There is a significant risk of seizures during aggressive reprogramming.
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Proc. West. Pharmacol. Soc. · Jan 2004
B vitamins increase the analgesic effect of ketorolac in the formalin test in the rat.
The purpose of this study was to assess the possible synergistic interaction between ketorolac and B-vitamins in the rat formalin test. Female Wistar rats were injected into the dorsal surface of the right hind paw with 50 microl of diluted formalin (1%). Reduction of number of flinches was considered as antinociception. ⋯ Theoretical ED25 values for the combination ketorolac-B vitamins estimated from the isobolograms were 140.3+/-15.1 and 80.4+/-6.8 mg/kg for 100:100:1 and 100:100:5 proportions, respectively. These values were significantly higher than experimental ED25 values which were 73.3+/-6.3 and 47.7+/-6.4 mg/kg for 100:100:1 and 100:100:5 proportions, respectively. Results indicate that oral ketorolac and B-vitamins can interact synergistically to reduce inflammatory pain in the formalin test and suggest the use of those combinations to relief this kind of pain in humans.
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Proc. West. Pharmacol. Soc. · Jan 2004
Effect of diclofenac on the antiallodynic activity of vitamin B12 in a neuropathic pain model in the rat.
B vitamins have been used as analgesic drugs to treat pain disorders associated with their deficiency. More recently it has been claimed that B vitamins are useful to relieve different pain states as carpal tunnel, migraine and premenstrual tension. In Latin America, B vitamins are commonly used to treat neuropathic pain; however, there is no data to support this indication. ⋯ Vitamin B12 (0.75-6 mg/kg), but not diclofenac (1-10 mg/kg), reduced in a dose-dependent manner tactile allodynia induced by spinal nerve ligation. Diclofenac (3.2 mg/kg) was not able to further increase vitamin B12-induced antiallodynia. Results indicate that vitamin B12, but not diclofenac, produces antiallodynic effects in the rat and suggest that this vitamin could be a potential treatment for neuropathic pain in humans.
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Proc. West. Pharmacol. Soc. · Jan 2004
Synergistic interaction between gabapentin and metamizol in the rat formalin test.
The purpose of this study was to assess the possible synergistic interaction between gabapentin and metamizol in the rat formalin test. Female Wistar rats were injected into the dorsal surface of the right hind paw with 50 microl of diluted formalin (1%). Formalin injection induced a typical flinching behavior indicating nociception. ⋯ Gabapentin (ED30 18.3+/-7.9 mg/kg), metamizol (ED30 139.2+/-6.2 mg/kg) and fixed-dose ratio gabapentin-metamizol combinations dose-dependently reduced flinching behavior during second phase of the test. Theoretical ED30 value for the combination estimated from the isobologram was 78.8+/-5.5 mg/kg, whereas that experimental ED30 value was 15.0+/-1.2 mg/kg. Results indicate that oral administration of gabapentin and metamizol can interact synergistically to reduce inflammatory pain in the formalin test and suggest the use of this combination to relieve pain in humans.