Pain
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The effects of nitrous oxide (N2O) are thought to be mediated by several pharmacological pathways at different levels of the central nervous system. Here, we focus on excitatory glutamatergic transmission in the superficial dorsal horn of the spinal cord with respect to its importance for the nociceptive processing. The effects of 50% N2O on electrically evoked and spontaneous excitatory glutamatergic transmission and on the response to exogenous administration of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-4-propionic acid (AMPA) receptor agonists were examined in lamina II neurons of adult rat spinal cord slices using the whole-cell patch-clamp technique. ⋯ Moreover N2O changed the distribution of miniature EPSC amplitude, but not frequency distribution in most neurons. N2O inhibits glutamatergic transmission in the superficial dorsal horn by modulating the NMDA- and AMPA-receptors. Our findings raise the possibility that the antinociceptive effect of N2O may be directly mediated at the level of the spinal cord.
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Comparative Study
The inventory of parent/caregiver responses to the children's pain experience (IRPEDNA): development and preliminary validation.
This paper describes the development and preliminary validation of a self-administered instrument designed to measure parents/caregivers' responses to children's pain episodes. For empirical validation purposes, a 60-item inventory was answered by 401 adults whose children's ages ranged from 6 to 16 years (mean=10.44, and SD=2.25 years). Factor structure and item analyses led to a 37 item inventory with three interrelated scales, namely: solicitousness (n=15 items), discouragement (n=10 items), and promotion of well-behaviors and coping (n=12 items). The three scales had good internal consistency, with coefficient alphas of 0.87, 0.83 and 0.87, respectively; they also showed good criterion-related validity.
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Comparative Study
Visceral and somatic hypersensitivity in a subset of rats following TNBS-induced colitis.
Chronic abdominal pain is one of the most common gastrointestinal symptoms experienced by patients. Visceral hypersensitivity has been shown to be a biological marker in many patients with chronic visceral pain. We have previously shown that IBS patients with visceral hypersensitivity also have evidence of thermal hyperalgesia of the hand/foot. ⋯ Transient colonic inflammation leads to chronic visceral and somatic hypersensitivity in a subset of rats. These findings are similar to the subset of patients who develop chronic gastrointestinal symptoms following enteric infection.
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Comparative Study
Involvement of ATP and its receptors on nociception in rat model of masseter muscle pain.
The exact mechanism of the masseter muscle pain recognized as a prominent symptom in temporomandibular disorders remains unclear, although it is clinically known that excessive muscular contraction causes tenderness in masseter muscles. It has been demonstrated that P2X3 receptors (P2X3Rs) in sensory neurons play a role in pain signaling from the periphery. We determined the role of P2X(3)R on pressure pain and mechanical hyperalgesia in a newly developed rat model of masseter muscle pain. ⋯ Moreover, administration of PPADS to the exerted masseter muscles produced a complete recovery of reducing PPT. Immunohistochemically, the number of P2X3R-positive neurons innervating the masseter muscles increased in the excessively contracted condition in trigeminal ganglia. Our results suggested that P2X3R plays an important role in pressure pain and mechanical hyperalgesia in masseter muscle caused by excessive muscular contraction.
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Randomized Controlled Trial Comparative Study
A randomized controlled trial of perioperative administration of pregabalin for pain after laparoscopic hysterectomy.
Pregabalin has anticonvulsant, antihyperalgesic, and anxiolytic properties. In this study we evaluated the control of pain after perioperative administration of pregabalin 300 or 600 mg, compared with diazepam 10mg. Altogether 91 women scheduled for laparoscopic hysterectomy were randomized to receive diazepam 10mg (D10), pregabalin 150 mg (P300) or 300 mg (P600) for premedication, and the dose was repeated after 12h, except for the D10 group, in which the patients received placebo. ⋯ The total dose of oxycodone (0-24h after surgery) was smaller in the P600 group than in the D10 group (0.34 vs. 0.45 mg kg(-1); P=0.046). The incidence of dizziness (70% vs. 35%; P=0.012), blurred vision (63% vs. 14%; P=0.002) and headache (31% vs. 7%; P=0.041) were higher in the P600 group than in the D10 group. In conclusion, perioperative administration of pregabalin 600 mg decreases oxycodone consumption compared with diazepam 10mg, but is associated with an increased incidence of adverse effects.