Genetic bases of the nutritional approach to migraine

Is calcitonin gene-related peptide (CGRP) the missing link in food histamine-induced migraine? A review of functional gut-to-trigeminovascular system connections

Calcitonin gene-related peptide (CGRP) and histamine plasma concentrations increase during migraine attacks. Both mediators are potent vasodilators, and they have been shown to reciprocally contribute to the release of each other in the trigeminovascular system, possibly driving migraine development. A high-histamine-content diet triggers migraine in patients who have histamine degradation deficiency owing to diaminooxidase (DAO) gene mutations. Therefore, studying functional links between exogenous histamine and CGRP seems promising for the understanding of diet-induced migraine generation. Notably, there is a lack of knowledge about the interplay of the enteric nervous system and the spinal/trigeminal somatosensory system with regard to CGRP and histamine. Based on background evidence, we propose that a functional interconnection between exogenous histamine and CGRP contributes to migraine development.

Migraine, Allergy, and Histamine: Is There a Link?

The relationship between migraines and allergies is controversial. Though they are epidemiologically linked, the underlying pathophysiological connection between them remains unclear. Migraines and allergic disorders have various underlying genetic and biological causes. As per the literature, these conditions are epidemiologically linked, and some common pathophysiological pathways have been hypothesized. The histaminergic system may be the clue to understanding the correlation among these diseases. As a neurotransmitter in the central nervous system with a vasodilatory effect, histamine has a well-documented influence on the allergic response and could be involved in the pathophysiology of migraines. Histamine may influence hypothalamic activity, which may play a major role in migraines or may simply influence their severity. In both cases, antihistamine drugs could prove useful. This review examines whether the histaminergic system, particularly H3 and H4 receptors, may provide a mechanistic link between the pathophysiology of migraines and allergic disorders, two common and debilitating conditions. Identifying their connection could help identify novel therapeutic strategies.

Single-cell RNA sequencing in the context of neuropathic pain: progress, challenges, and prospects

Neuropathic pain, characterized by persistent or intermittent spontaneous pain as well as some unpleasant abnormal sensations, is one of the most prevalent health problems in the world. Ectopic nerve activity, central and peripheral nociceptive sensitization and many other potential mechanisms may participate in neuropathic pain. The complexity and ambiguity of neuropathic pain mechanisms result in difficulties in pain management, and existing treatment plans provide less-than-satisfactory relief. In recent years, single-cell RNA sequencing (scRNA-seq) has been increasingly applied and has become a powerful means for biological researchers to explore the complexity of neurobiology. This technique can be used to perform unbiased, high-throughput and high-resolution transcriptional analyses of neuropathic pain-associated cells, improving the understanding of neuropathic pain mechanisms and enabling individualized pain management. To date, scRNA-seq has been preliminarily used in neuropathic pain research for applications such as compiling a dorsal root ganglion atlas, identifying new cell types and discovering gene regulatory networks associated with neuropathic pain. Although scRNA-seq is a relatively new technique in the neuropathic pain field, there have been several studies based on animal models. However, because of the various differences between animals and humans, more attention should be given to translational medicine research. With the aid of scRNA-seq, researchers can further explore the mechanism of neuropathic pain to improve the clinical understanding of the diagnosis, treatment and management of neuropathic pain.

Age-Dependent Levels of Protein Kinase Cs in Brain: Reduction of Endogenous Mechanisms of Neuroprotection

Neurodegenerative diseases are among the leading causes of mortality and disability worldwide. However, current therapeutic approaches have failed to reach significant results in their prevention and cure. Protein Kinase Cs (PKCs) are kinases involved in the pathophysiology of neurodegenerative diseases, such as Alzheimer's Disease (AD) and cerebral ischemia. Specifically ε, δ, and γPKC are associated with the endogenous mechanism of protection referred to as ischemic preconditioning (IPC). Existing modulators of PKCs, in particular of εPKC, such as ψεReceptor for Activated C-Kinase (ψεRACK) and Resveratrol, have been proposed as a potential therapeutic strategy for cerebrovascular and cognitive diseases. PKCs change in expression during aging, which likely suggests their association with IPC-induced reduction against ischemia and increase of neuronal loss occurring in senescent brain. This review describes the link between PKCs and cerebrovascular and cognitive disorders, and proposes PKCs modulators as innovative candidates for their treatment. We report original data showing εPKC reduction in levels and activity in the hippocampus of old compared to young rats and a reduction in the levels of δPKC and γPKC in old hippocampus, without a change in their activity. These data, integrated with other findings discussed in this review, demonstrate that PKCs modulators may have potential to restore age-related reduction of endogenous mechanisms of protection against neurodegeneration.