Pain
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The co-occurrence of bruxism, temporomandibular disorders (TMDs), and headache is common in patients. However, there is conflicting evidence regarding whether this association is simply a result of their high prevalence or whether there are indeed causal relationships. This review provides an overview of the current state of research while taking into account the controversies surrounding research methods, particularly in definitions and diagnostic standards. ⋯ Treatment wise, it is important to differentiate all 3 conditions because treatment of one condition may have an effect on the other 2 without proving causality. For future research, it is crucial to establish greater consistency and applicability in diagnostic procedures and definitions. In addition, more experimental and clinical studies investigating the question of causality are needed.
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For decades, clinicians and researchers have observed bidirectional relationships between child development and the pain experience in childhood. Pain in childhood is an inherently developmental phenomenon, embedded in an iterative, time-dependent process that reflects individual biological, behavioral, social, psychological, and environmental characteristics that unfold across the early life span. Childhood pain can have wide ranging effects on brain development in ways that contribute-for better and worse-to social, emotional, and cognitive well-being in childhood and on into adulthood. ⋯ In this paper, pain will be considered as a determinant of development, and conversely development will be considered as a key determinant of a child's pain experience. We will discuss how intersectional identities (eg, gender, race, socioeconomic status) and associated social, structural, systemic, and physical environments influence the relationship between development and pain. Finally, we will identify what might be needed to think "developmentally" in ways that extend from the "bench side" in the lab to the "curb side" in the community, integrating a developmental perspective into research and clinical practice to achieve health accessibility and equity in pain care for all children across the developmental spectrum.
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While our understanding of pain is rapidly growing, some areas of pain research are lagging behind. This article discusses two current and inter-related gaps in knowledge that are in need of addressing: first, the connections between "brain" and "body" components of pain; and second, the process of endogenous pain resolution. ⋯ These include comprehensive mapping of the mechanosensory and nociceptive innervation of deep tissues; developing objective, non-invasive measurements to quantify the metabolic, structural and mechanical components of the peripheral tissue environment; integrating our understanding of pain pathophysiology, across whole organs and whole body, as well as across bio-psycho-social domains; and understanding the interplay of nervous system and peripheral tissue mechanisms that promote the endogenous resolution of pain and prevent its acute-to-chronic transition. Current NIH-led efforts in these areas are outlined, including several studies within the NIH HEAL (or Help End Addition Long Term) initiative and the National Center for Complementary and Integrative Health's strategic priorities in whole person research.
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Cannabidiol (CBD), the main nonpsychoactive cannabinoid of cannabis, holds promise for nonaddictive treatment of pain. Although preclinical studies have been encouraging, well-controlled human trials have been largely unsuccessful. To investigate this dichotomy and better understand the actions of CBD, we used high-content calcium imaging with automated liquid handling and observed broad inhibition of neuronal activation by a host of ionotropic and metabotropic receptors, including transient receptor potential (Trp) and purinergic receptors, as well as mediators of intracellular calcium cycling. ⋯ Taken together, these results demonstrate that CBD can reduce neuronal activity evoked by a strikingly wide range of stimuli implicated in pain signaling. The extensive effects underscore the need for further studies at substantially lower drug concentrations, which are more likely to reflect physiologically relevant mechanisms. The slow kinetics and block raise biophysical questions regarding the lipophilic properties of CBD and its action on channels and receptors within membranes.