Pain
-
We investigated the involvement of de novo neurosteroid synthesis in the mechanisms underlying the analgesic and antihyperalgesic effects of N-palmitoylethanolamine (PEA) in two models of acute and persistent pain, the formalin test and carrageenan-induced paw edema. The pivotal role of peroxisome proliferator-activated receptor (PPAR)-α in the antinocifensive effect of PEA was confirmed by the lack of this effect in PPAR-α-null mice. ⋯ In agreement with those data, in both pain models, PEA administration in challenged mice specifically restored the expression of two proteins involved in neurosteroidogenensis, the steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage (P450scc) in the ipsilateral horns of spinal cord, without affecting their expression in the contralateral side. These results provide new information about the involvement of de novo neurosteroid synthesis in the modulation of pain behavior by PEA.
-
The aim of this study was to test the capacity of the Fear Avoidance Model to explain the relationship between pain and disability in patients with whiplash-associated disorders. Using the method of Baron and Kenny, we assessed the mediating effect of fear of movement on the cross-sectional and longitudinal relationships between pain and disability. Two hundred and five subjects with neck pain due to a motor vehicle accident provided pain intensity (0 to 10 numerical rating scale), fear of movement (Tampa Scale of Kinesiophobia and Pictorial Fear of Activity Scale) and disability (Neck Disability Index) scores within 4 weeks of their accident, after 3 months, and after 6 months. ⋯ Contrary to our initial hypothesis, the proportion of the total effect of pain on disability that was mediated by fear of movement did not substantially change as increasing time elapsed after the accident. The proportion mediated was slightly higher when fear of movement was measured by Tampa Scale of Kinesiophobia as compared with Pictorial Fear of Activity Scale. The findings of this study suggest that the Fear Avoidance Model plays a role in explaining a moderate proportion of the relationship between pain and disability after whiplash injury.