European journal of pain : EJP
-
Spironolactone, a commonly used mineralocorticoid receptor antagonist, has been reported to potentiate the effect of morphine in the rat. The aim of this study was to investigate the effects of spironolactone on morphine antinociception and tissue distribution. ⋯ Spironolactone has no antinociceptive effects in thermal models of pain, but it enhances the antinociceptive effects of morphine mainly by increasing morphine central nervous system concentrations, probably by inhibiting P-gp.
-
Cold allodynia and cold hyperalgesia are both elusive features of neuropathic pain, particularly in patients with various polyneuropathies. Numerous studies have suggested that topical application of L-menthol causes temporary cold hypersensitivity and thus acts as a proxy for associated symptoms. This review summarizes studies on L-menthol-induced nociception, cold allodynia and cold hyperalgesia in vitro, in animals and in humans. ⋯ Topical high-concentration L-menthol consistently induces cold hypersensitivity in animals and humans, thus constituting a predictable surrogate model of cold allodynia and hyperalgesia. Understanding translational features of this model and its underlying mechanisms could be valuable in preclinical and human phases of drug development and in improving current treatment of patients with polyneuropathy.
-
Review
Heart rate variability and experimentally induced pain in healthy adults: A systematic review.
Reactivity of the autonomic nervous system to experimental pain stimuli has been extensively studied using measures of heart rate and blood pressure. Heart rate variability (HRV) attempts to tease out the relative contributions of sympathetic and parasympathetic activity in the autonomic control of the heart and may therefore be more appropriate to investigate autonomic response to short-term nociceptive stimulation in detail. The current evidence on HRV and experimentally induced pain has not yet been synthesized within a systematic review. ⋯ HRV has several advantages compared to other measures of autonomic reactivity in studies investigating physiological response to nociceptive stimulation. Future studies should focus on comparisons between different methods of pain induction, interindividual variability in pain sensitivity by baseline autonomic activity, and the implications of both on the use of HRV within routine clinical evaluations.
-
Chemokine (C-C motif) ligand 2 (CCL2) participates in different mechanisms contributing to the spinal cord inflammation and pain development after sciatic nerve injury. Recent data also support its role in orofacial thermal hypersensitivity, although its implication in different phases of trigeminal pain emergence is unclear. We assessed the importance of CCL2 signalling in biochemical and behavioural alterations during the early and late stages following chronic constriction injury of infraorbital nerve (ION-CCI), a model of peripheral traumatic trigeminal pain. ⋯ Our data suggest that CCL2 is involved principally in the early events accompanying the ION lesion rather than in long-term alterations and the maintenance of trigeminal mechanical hypersensitivity.