Int Rev Neurobiol
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Neuropathic pain in the orofacial region is the clinical manifestation of trigeminal nerve injury following oral surgeries such as tooth extraction, dental implantation or tooth pulp treatment. Normally non-noxious touching of the facial skin or oral mucosa elicits strong pain named allodynia, and normally noxious stimulation causes intolerable pain named hyperalgesia in the trigeminal neuropathic pain patients. ⋯ In this chapter, we are focusing on trigeminal neuropathic pain, and describe our recent studies using animal models of trigeminal neuropathic pain. We also present the clinical assessment of trigeminal neuropathic pain patients to develop the appropriate treatment of trigeminal neuropathic pain.
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Over the years it has become clear that the biological clock acts at different levels, ranging from the control of gene expression, protein stability, or subcellular localization of key proteins, to the fine tuning of network properties and modulation of input signals, ultimately ensuring that the organism will be best synchronized to a changing environment at the physiological and behavioral levels. The purpose of this chapter is to discuss the circadian control of clock outputs, spanning the most immediate ones within pacemaker neurons (i.e., membrane excitability, release of neurotransmitters, structural changes) to the circadian modulation of different behaviors (locomotor activity, learning and memory, social interaction), with a focus on the examples that shed light on the surprising degree of plasticity that characterizes the underlying circuits.
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Dreams have been studied from different perspectives: psychoanalysis, academic psychology, and neurosciences. After presenting the definition of dreaming and the methodological tools of dream research, the major findings regarding the phenomenology of dreaming and the factors influencing dream content are briefly reviewed. ⋯ Dreams also have an effect on subsequent waking life, e.g., on daytime mood and creativity. The question about the functions of dreaming is still unanswered and open to future research.
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The catechol-O-methyltransferase (COMT) gene is of significant interest to neuroscience, due to its role in modulating dopamine function. COMT is dynamically regulated; its expression is altered during normal brain development and in response to environmental stimuli. ⋯ COMT contains several functional polymorphisms and haplotypes, including the well-studied Val158Met polymorphism. Here I review the regulation of COMT and the functional polymorphisms within its sequence with respect to brain function.
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In animals, different types of COMT inhibitors, irrespective of their brain penetration, are pro-nociceptive in several models of acute and inflammatory pain. Similarly, COMT knock-out mice are more sensitive to nociceptive stimuli, whereas in mice over-expressing a high activity COMT variant nociceptive sensitivity is decreased. COMT knock-out mice also show altered response to opioids and stress-induced analgesia. ⋯ In chronic clinical pain, the effect of COMT polymorphisms depends on the pain conditions. Hence, in neuropathic and cancer pains, COMT activity is meaningless but in some chronic musculoskeletal pain conditions and migraine or headache low COMT activity appears to increase incidence and symptoms. A low COMT activity also increases availability of opioid receptors and may enhance opioid analgesia and adverse effects at least in cancer pains.