Articles: hyperalgesia.
-
The importance of the GABAergic system in spinal nociceptive processing has long been appreciated but we have only recently begun to understand how this system is modulated by the regulation of anion gradients. In neuronal tissues, cation-chloride cotransporters regulate Cl- homeostasis and the activity and/or expression of these transporters has important implications for the direction and magnitude of anion flow through GABA-A channels. ⋯ On the other hand, KCC2 expression is reduced in dorsal horn neurons following peripheral nerve injury resulting in a loss of GABA-/glycinergic inhibitory tone and, in some cases, inverting its action into net excitation. Pharmacological targeting of these cation chloride cotransporters to restore normal GABA-/glycinergic transmission in the spinal cord represents an entirely novel approach to the development of analgesics.
-
Our aims were to determine whether subjects with painful bladder syndrome (PBS) demonstrate characteristics of visceral pain syndromes: visceral hyperalgesia, expanded loci of referral of bladder sensation, increased bladder pain with repetitive filling, lower thresholds to cutaneous stimulation in relevant dermatomes, abnormal response to repetitive cutaneous stimulation in relevant dermatomes, and also to develop easily applied measures for PBS pain evaluation and management. ⋯ PBS subjects demonstrate bladder hyperalgesia and may sense bladder discomfort at sites other than suprapubic. Rating of bladder discomfort and sensory mapping during cystometry usefully distinguishes between PBS subjects and controls.
-
Comparative Study
Activation of p38 MAPK in primary afferent neurons by noxious stimulation and its involvement in the development of thermal hyperalgesia.
Alterations in the intracellular signal transduction pathway in primary afferents may contribute to pain hypersensitivity. We demonstrated that very rapid phosphorylation of p38 mitogen-activated protein kinase occurred in dorsal root ganglion (DRG) neurons that were participating in the transmission of noxious signals. Capsaicin injection induced phosphorylated-p38 (p-p38) in small-to-medium diameter sensory neurons with a peak at 2 min after capsaicin injection. ⋯ Intrathecal administration of the p38 inhibitor, FR167653, reversed the thermal hyperalgesia produced by the capsaicin injection. Inhibition of p38 activation was confirmed by the decrease in the number of p-p38-IR neurons in the DRG following capsaicin injection. Taken together, these findings suggest that the activation of p38 pathways in primary afferents by noxious stimulation in vivo may be, at least in part, correlated with functional activity, and further, involved in the development of thermal hyperalgesia.
-
The present study was conducted to test the hypothesis that the peripheral 5-hydroxytryptamine (5-HT)2A receptor is involved in inflammatory hyperalgesia and production of noxious stimulus-induced neuronal activity at the level of the spinal cord dorsal horn. Intraplantar (i.pl.) injection of carrageenan dramatically reduced paw withdrawal latency to noxious heat (47 degrees C) and caused paw swelling. Pretreatment with ketanserin, a selective antagonist of 5-HT2A receptor, in the hindpaw produced dose-dependent inhibition of the hyperalgesia (0.5, 3 and 5 mug; i.pl.) with full relief at 5 mug. ⋯ Ketanserin (5 mug) markedly reduced carrageenan-induced FLI in all laminae of the dorsal horn. However, blockade of peripheral 5-HT1A receptors by (N-2-[4-(2-methoxyphenyl-1-piperazinyl] ethyl]-N-2-pyridinylcyclohexanecarboxamide at maximally effective doses (30 and 100 mug; i.pl.) did not alter carrageenan-induced hyperalgesia, edema or expression of FLI. The present study provided evidence at cellular level that the peripheral 5-HT2A receptor is preferentially involved in the development of thermal hyperalgesia in the carrageenan model of inflammation.
-
Schweiz Monatsschr Zahnmed · Jan 2005
[Therapeutic local anesthesia for the management of atypical odontalgia. A clinical case series].
The management of patients diagnosed with atypical odontalgia (AO) is a challenging task. The aim of this longitudinal clinical case series was to document the effect of a 4% carticaine solution without epinephrine among ten patients with AO. Once or on two successive days, 1.7 ml of the local anesthetics was injected buccally in the area of the perceived pain. ⋯ Patient satisfaction was not significantly associated with the amount of pain reduction. Considering the limited treatment options and their side effects, injections with epinephrine-free carticaine seem to be a measure worth to be taken into consideration. Although results gained from uncontrolled case series have to be interpreted with caution, the findings of this observational study sound promising.