Articles: hyperalgesia.
-
No study has previously analyzed pressure pain sensitivity of nerve trunks in migraine. This study aimed to examine the differences in mechanical pain sensitivity over specific nerves between patients with unilateral migraine and healthy controls. ⋯ In patients with unilateral migraine, we found increased mechano-sensitivity of the supra-orbital nerve on the symptomatic side of the head. Outside the head, the same patients showed increased mechano-sensitivity of the main peripheral nerves of both upper limbs, without asymmetries. Such diffuse hypersensitivity of the peripheral nerves lends further evidence to the presence of a state of hyperexcitability of the central nervous system in patients with unilateral migraine.
-
Korean J. Intern. Med. · Jun 2009
Effect of the combined use of tramadol and milnacipran on pain threshold in an animal model of fibromyalgia.
Acidic saline injections produce mechanical hyperresponsiveness in male Sprague-Dawley rats. We investigated the effect of milnacipran in conjunction with tramadol on the pain threshold in an acidic saline animal model of pain. ⋯ We observed potentiation of the antihyperalgesic effect when milnacipran and tramadol were administered in combination in an animal model of fibromyalgia. Further research is required to determine the efficacy of various combination treatments in fibromyalgia in humans.
-
Comparative Study
Deficiency in endogenous modulation of prolonged heat pain in patients with Irritable Bowel Syndrome and Temporomandibular Disorder.
Females with Irritable Bowel Syndrome (IBS) and Temporomandibular Disorder (TMD) are characterized by enhanced sensitivity to experimental pain. One possible explanation for this observation is deficiencies in pain modulation systems such as Diffuse Noxious Inhibitory Control (DNIC). In a few studies that used brief stimuli, chronic pain patients demonstrate reduced DNIC. ⋯ Compared to controls, IBS and TMD patients reported an increased sensitivity to heat pain and failed to demonstrate pain inhibition due to DNIC. Controls showed a significant reduction in pain during the DNIC session. These findings support the idea that chronic pain patients are not only more pain sensitive but also demonstrate reduced pain inhibition by pain, possibly because of dysfunction of endogenous pain inhibition systems.
-
Previous studies on pressure pain sensitivity in patients with migraine have shown conflicting results. There is emerging evidence suggesting that pain sensitivity is not uniformly distributed over the muscles, indicating the existence of topographical changes in pressure pain sensitivity. The aim of this study was to calculate topographical pressure pain sensitivity maps of the temporalis muscle in a blind design in patients with strictly unilateral migraine compared with controls. ⋯ Within the migraine group, PPT levels were decreased bilaterally from the posterior to the anterior column of the temporalis muscle (Student-Newman- Keuls analysis; P < 0.05), with the most sensitive in the anterior part of the muscle. For controls, PPT did not follow such anatomical distribution, the most sensitive point being the centre of the mid-muscle belly. This study showed bilateral sensitization to pressure in unilateral migraine, suggesting the involvement of central components.
-
Can. J. Physiol. Pharmacol. · Jun 2009
URB597, an inhibitor of fatty acid amide hydrolase, reduces hyperalgesia in diabetic rats.
Diabetic rats display increased pain responses after injection of formalin into the paw or thermal stimulation of the tail, suggesting the presence of hyperalgesia. In this study, we investigated the efficacy of URB597 (0.1, 0.3, and 0.5 mg/kg, i.p.), an inhibitor of endocannabinoids metabolism, on 2 models of experimental hyperalgesia in streptozotocin (STZ)-induced diabetic rats. Animals were divided into control, URB597-treated control (0.1, 0.3, and 0.5 mg/kg), diabetic, and URB597-treated diabetic (0.1, 0.3, and 0.5 mg/kg) groups. ⋯ URB597 treatment did not affect body weight or plasma glucose level of treated animals compared with nontreated animals. This study shows that increasing endocannabinoid neurotransmission with URB597 displays efficacy in chemical and thermal models of diabetic hyperalgesia. It also suggests that URB597 is a promising tool for treatment of painful diabetic neuropathy.