Pain
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Arthropods are the largest group of living organisms, and among them, mosquitoes spread parasites and viruses causing deadly diseases. They can easily spread these pathogens because of their painless skin piercing. Although the lack of pain is mainly due to the thinness of their fascicle, it is possible that mosquito saliva, which is discharged during their piercing, might also contribute to it. ⋯ Finally, we confirmed the antinociceptive effects of mosquito head homogenates, mouse saliva, and sialorphin in vivo by observing decreased pain-related behaviors in mice coinjected with these substances. Similar inhibitory effects of mosquito head homogenates and mouse saliva on TRPV1 and TRPA1 suggest that the antinociceptive effects of saliva are universal, which could explain why many animals including humans often lick their wounds. These findings would lead to the development of novel and safe antinociceptive agents.
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Because chronic pain has been poorly represented in the International Statistical Classification of Diseases and Related Health Problems (ICD) despite its significant contribution to the burden of disease worldwide, the International Association for the Study of Pain (IASP) developed a classification of chronic pain that was included in the ICD-11 version as "MG30" and approved by the World Health Assembly in 2019. The objective of this field test was to determine how well the classification of chronic pain works in the context of the ICD-11. A web-based survey using the WHO-FiT platform recruited 177 healthcare professionals from all WHO regions. ⋯ The case coding was on average 83.9% accurate, only in 1.6% of cases any difficulty was perceived. The morbidity rules were applied correctly in 74.1% of cases. From a coding perspective, the ICD-11 is superior to the ICD-10 in every respect, offering better accuracy, difficulty, and ambiguity in coding chronic pain conditions.
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Chronic pain is associated with mental and physical health difficulties and is prevalent among veterans. Cannabis has been put forth as a treatment for chronic pain, and changes in laws, attitudes, and use patterns have occurred over the past 2 decades. Differences in prevalence of nonmedical cannabis use and cannabis use disorder (CUD) were examined across 2 groups: veterans or nonveterans and those reporting or not reporting recent pain. ⋯ Among veterans, the prevalence of frequent cannabis use was greater among those with pain (PD = 1.92%, 98% CI [0.21-3.63]), and among veterans residing in a state with MCLs, the prevalence of CUD was greater among those reporting recent pain (PD = 3.88%, 98% CI [0.36-7.39]). Findings failed to support the hypothesis that cannabis use improves mental or physical health for veterans with pain. Providers treating veterans with pain in MCL states should monitor such patients closely for CUD.
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Attentional bias to pain-related information may contribute to chronic pain maintenance. It is theoretically predicted that attentional bias to pain-related language derives from attentional bias to painful sensations; however, the complex interconnection between these types of attentional bias has not yet been tested. This study aimed to investigate the association between attentional bias to pain words and attentional bias to the location of pain, as well as the moderating role of pain-related interpretation bias in this association. ⋯ This indicates that congruency between the locations of pain and pain-related information may strengthen attentional bias. Overall, these findings indicate that cognitive biases to pain-related information interact with cognitive biases to somatosensory information. The implications of these findings for attentional bias modification interventions are discussed.
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Gain-of-function and loss-of-function mutations in Nav1.7 cause chronic pain and pain insensitivity, respectively. The preferential expression of Nav1.7 in the peripheral nervous system and its role in human pain signaling make Nav1.7 a promising target for next-generation pain therapeutics. However, pharmacological agents have not fully recapitulated these pain phenotypes, and because of the lack of subtype-selective molecular modulators, the role of Nav1.7 in the perception of pain remains poorly understood. ⋯ Makatoxin-3 acts on the S3-S4 loop of voltage sensor domain IV (VSD4) of Nav1.7, which causes a hyperpolarizing shift in the steady-state fast inactivation and impairs inactivation kinetics. We also determined the key residues and structure-function relationships for the toxin-channel interactions, which are distinct from those of other well-studied α toxins. This study not only reveals a new mechanism underlying BV-evoked pain but also enriches our knowledge of key structural elements of scorpion toxins that are pivotal for toxin-Nav1.7 interactions, which facilitates the design of novel Nav1.7 selective modulators.