European journal of pain : EJP
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Slowing refers to the gradual decrease in conduction velocity evoked by repetitive electrical stimuli. The underlying mechanisms are still poorly understood, and its physiological/pathological relevance scarcely discussed; however, changes in axonal conduction properties might unmask abnormal nociceptor function and alter the encoding time window at the spinal cord. ⋯ Under our experimental conditions, slowing seems largely dependent on functional Ih . The marked decrease in slowing after axotomy in C-fibres fits with the increased expression of functional hyperpolarization-activated/HCN channel current and may underlie the analgesic effects of the specific Ih blocker ZD7288 previously described in neuropathic pain models.
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Fibromyalgia syndrome (FMS) is frequently associated with psychiatric conditions, particularly anxiety. Deficits in contingency learning during fear conditioning have been hypothesized to increase anxiety and, consequently, pain sensation in susceptible individuals. The goal of this study was to examine the relationship between contingency learning and pain experience in subjects with FMS and rheumatoid arthritis (RA). ⋯ Contingency learning deficits represent a potentially promising and specific, but largely unstudied, psychopathological factor in FMS. Deficits in contingency learning may increase anxiety and, consequently, pain sensation. These findings have the potential to contribute to the development of novel therapeutic approaches for FMS.