European journal of pain : EJP
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Opioids are used for the treatment of pain. However, 30-50% of patients have insufficient effect to the opioid initially selected by the physician, and there is an urgent need for biomarkers to select responders to the most appropriate drug. Since opioids mediate their effect in the central nervous system, this study aimed to investigate if electroencephalography (EEG) during rest or pain before treatment could predict the analgesic response. ⋯ Machine learning based on EEG before treatment enabled separation between responders and non-responders. This study represents the first step towards the prediction of opioid analgesia based on EEG features prior to drug administration, and advocates for the use of machine learning in future studies.
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Hind paw injection of complete Freund's adjuvant (CFA) is a commonly used sub-acute inflammatory pain model in rodents with typical subjective endpoint measurements of paw withdrawal to thermal or mechanical stimuli. ⋯ The results presented here demonstrate that CRANE provides an objective assessment of pain behaviours for sub-acute inflammatory pain in rats. The pharmacological profile of standard analgesics supports that CRANE model may potentially be used to identify novel analgesic agents for the treatment of sub-acute inflammatory pain.
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Chemotherapeutic agents, such as cisplatin, are known to induce a persistent polyneuropathy. The mechanisms underlying the development of this pain are complex, and have only been investigated rodent models using male animals, despite an equivalent presentation of neuropathy between the sexes, clinically. ⋯ It is important to continue examining both sexes in various pain models, as a mononeuropathy and polyneuropathy show sex differences in pain development and the role of TLR signalling.
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Allodynia and hyperalgesia present after surgical interventions are often a major complain of surgical patients. It is thought that both peripheral and central mechanisms contribute to these symptoms. In this study, the role of peripheral nerve fibres that express transient receptor potential vanilloid 1 (TRPV1) receptors in the activation of spinothalamic tract (STT) and postsynaptic dorsal column (PSDC) neurons was assessed in a model of surgical pain. ⋯ Our results suggest that activation of both STT and PSDC neurons is involved in development of pain states present after surgical incision and that TRPV1-containing peripheral nerve fibres are needed for c-Fos expression in these dorsal horn neurons after plantar incision.