European journal of pain : EJP
-
Interruption of a continuous noxious heat by a relatively greater noxious heat evokes reductions in pain experience when the original noxious heat returns. The reduction is greater than that evoked by continuous delivery of noxious heat. This disproportionate reduction in pain experience, known as offset analgesia, is presumably mediated by a mechanism different to adaptation or habituation. ⋯ There was no attenuation effect for the unchanging stimuli delivered across the 3 days of testing but attenuation effects enhanced the offset analgesia resulting in a larger offset analgesia effect on days 2 and 3. It is possible that offset analgesia and attenuation are mediated by inter-related mechanisms. Further studies might investigate whether offset analgesia involves inhibitory structures such as the PAG-RVM.
-
Carriers of a particular haplotype of the GTP cyclohydrolase gene (GCH1) had less pain after surgery for chronic lumbar radiculopathy and a decreased sensitivity to some experimental mechanical pain stimuli. Ex-vivo, GCH1 upregulation and BH4 production after forskolin stimulation were reduced, while baseline BH4 concentrations were not affected. This suggested that the haplotype may mainly exert its modulating function when the GCH1 system is provoked. The present study aimed at (i) testing this hypothesis and (ii) independently reproducing the pain-decreasing effects of a particular GCH1 haplotype having been previously associated with pain protection. ⋯ This study verifies previous results that decreased GCH1 function or inducibility as a result of genetic polymorphisms protects against pain. This study extents previous results by showing that this pain protection is mainly conferred under conditions of hyperalgesia resulting from sensitization, supporting specific functions of BH4 in relation to particular aspects of pain.
-
Antidepressant drugs act mainly by blocking the noradrenaline and/or serotonin uptake sites and require a chronic treatment. Tricyclic antidepressants are among the first line treatments clinically recommended against neuropathic pain. As observed against depression, a chronic treatment is required for a therapeutic effect. ⋯ For comparison, we tested the anticonvulsant gabapentin and showed that it alleviates neuropathic allodynia after 3 days of treatment. Naloxone had no effect on gabapentin therapeutic benefit, showing that antidepressants and anticonvulsants alleviate neuropathic allodynia through independent mechanisms. Our work provides a clinically relevant model to understand the mechanism by which chronic antidepressant treatment can alleviate neuropathic pain.
-
The term whiplash associated disorders (WAD) includes a wide range of complaints, with neck pain as predominating symptom. Living with long term pain influences quality of life. In previous studies of other chronic pain patients, subgrouping has been made according to thermal pain thresholds measured in quantitative sensory testing (QST). ⋯ Thermal pain hyperalgesia, especially for cold, seems to be a determinant for subgrouping WAD patients. These results support that such a classification of a heterogenous group could be of importance in tailoring treatment and early interventions.
-
Multicenter Study Clinical Trial
Efficacy and safety of pregabalin in patients with diabetic peripheral neuropathy or postherpetic neuralgia: Open-label, non-comparative, flexible-dose study.
We assessed the efficacy and safety of a flexible-dose pregabalin regimen in patients with diabetic peripheral neuropathy (DPN) or postherpetic neuralgia (PHN) under clinical practice conditions. Further, the trial investigated the correlation of unspecific measures of change (patient and physician global impression of change, PGIC and CGIC) and specific measures of morbidity. The primary outcomes of this prospective, open-label, non-controlled study were the correlation between global status (PGIC and CGIC) and changes in pain, sleep, and anxiety scores as assessed on numerical or visual rating scales. ⋯ In conclusion, pregabalin in a flexible-dose regimen improved pain, sleep, anxiety and general state, and was well tolerated. The efficacy and safety profile of pregabalin was consistent with the data from the controlled clinical trials. The PGIC and CGIC and the specific pain and sleep scores, but not the anxiety score were generally well correlated but not synonymous.