A recent study, using laboratory mice, discovered a physical link within the brain that may explain why headaches are more severe than pain we experience in other parts of the body. Pain perception involves both the physical sensation of pain and the emotional response to that pain. There are physical structures within the brain that regulate both, but until now, a direct link between the two had only been hypothesized.
An ability to adapt to changes in oxygen availability is essential for survival in both prokaryotic and eukaryotic organisms. Recently, cation channels encoded by the transient receptor potential (trp) gene superfamily have been recognized as multimodal sensors of a wide variety of factors inside the cells and in the extracellular environment and also as transducers of electrical and chemical signals mediated by ions such as Ca2+.
To understand a possible role for transient potential receptor vanilloid 1 (TRPV1) ion channels in sumatriptan relief of pain mediated by trigeminal nociceptors.
Transient receptor potential (TRP) channels, a family of structurally related proteins have been implicated in the sensation of pain and hyperalgesia caused by exogenous and endogenous agonists, as well as touch, pH, and temperature. The objective of this study was to determine the effects of tooth injury on the expression of the cold sensitive channel TRPA1, in the trigeminal ganglion, the primary source of sensory and nociceptive innervation of teeth.
The California bay laurel or Umbellularia californica (Hook. & Arn.) Nutt., is known as the ‘headache tree’ because the inhalation of its vapours can cause severe headache crises. However, the underlying mechanism of the headache precipitating properties of Umbellularia californica is unknown. The monoterpene ketone umbellulone, the major volatile constituent of the leaves of Umbellularia californica, has irritating properties, and is a reactive molecule that rapidly binds thiols.
The neurological mechanisms leading to headache pain are complex and poorly understood. Genetic studies of familial migraine conditions have provided important insights into the potential physiological causes underlying headache conditions.
Pain perception begins with the activation of primary sensory nociceptors. Over the past decade, flourishing research has revealed that members of the Transient Receptor Potential (TRP) ion channel family are fundamental molecules that detect noxious stimuli and transduce a diverse range of physical and chemical energy into action potentials in somatosensory nociceptors. Here we highlight the roles of TRP vanilloid 1 (TRPV1), TRP melastatin 8 (TRPM8) and TRP ankyrin 1 (TRPA1) in the activation of nociceptors by heat and cold environmental stimuli, mechanical force, and by chemicals including exogenous plant and environmental compounds as well as endogenous inflammatory molecules.
Vanilloid receptor-1 (TRPV1) is a nonselective cation channel,
predominantly expressed by sensory neurons, which plays a
key role in the detection of noxious painful stimuli such as
capsaicin, acid, and heat. TRPV1 antagonists may represent
novel therapeutic agents for the treatment of a range of conditions
including chronic pain, migraine, and gastrointestinal
Vanilloid receptor 1 (TRPV1) is activated by chemical ligands and heat. In this study, we found that each of the group B antagonists competed with and prevented BCTC, AMG6880 or AMG7472 antagonism of rat TRPV1 activation by protons with pA2 values similar to those for blocking capsaicin, indicating that proton activation does not alter the conformation of the TRPV1 capsaicin-binding pocket. In conclusion, group A antagonists seem to lock the channel conformation in the closed state, blocking both capsaicin and proton activation.
Drosophila melanogaster flies carrying the trp (transient receptor potential) mutation are rapidly blinded by bright light, because of the absence of a Ca2+-permeable ion channel in their photoreceptors. The identification of the trp gene and the search for homologs in yeast, flies, worms, zebrafish and mammals has led to the discovery of a large superfamily of related cation channels, named TRP channels. Activation of TRP channels is highly sensitive to a variety of chemical and physical stimuli, allowing them to function as dedicated biological sensors that are essential in processes such as vision, taste, tactile sensation and hearing.