Phytothérapie de la dépression

Editorial

Le changement     

Génétique de la migraine

The principal advances in understanding of the molecular genetics of migraine come from studies of familial hemiplegic migraine (FHM), a rare migraine variant with aura, which has autosomal dominant inheritance. Three genes have been identified, all of which code for ion transporters. In cellular models and in transgenic mice, mutations causing FHM result in neuronal hyperexcitability, thus facilitating the triggering of waves of cortical spreading depression, the phenomenon which underlies the migrainous aura. Large numbers of linkage analysis and association studies in the most common forms of migraine, whether with or without aura, have yielded inconclusive results. This is probably due to the clinical heterogeneity of migraine. New methods of phenotype analysis and of exploration of association over the whole genome now seem to offer the best chance of identifying the genes of migraine.     

Modulation de la douleur après stimulation cérébrale profonde dans la maladie de Parkinson : revue de la littérature

Pain is one of the most invalidating non motor symptoms in Parkinson’s disease (PD) patients and remains insufficiently diagnosed and treated. Deep brain stimulation of subthalamic nucleus (DBS-STN), that has been shown to be very effective in the treatment of motor symptoms, can also improve painful phenomenon in PD patients thanks to a central modulation of pain detection and tolerance thresholds.     

Prédiction de la douleur postopératoire sévère et de la persistance de la douleur postchirurgicale par des tests psychophysiques

Psychophysical testing has the potential to identify patients at risk for severe postsurgical pain and for developing persistent postsurgical pain. Identification of that risk should allow for better preemptive actions. However, the clinimetric characteristics of these tests are barely defined. Consequently, their predictive value remains limited and needs to be refined in order to be exploitable at the bedside with standardized protocols and normative data for surgical patients.     

Apport de l’imagerie fonctionnelle cérébrale dans la physiopathologie de la migraine

Résumé  L’utilisation des techniques d’imagerie fonctionnelle cérébrale dans la migraine a permis de préciser in vivo chez l’Homme sain, un certain nombre d’hypothèses physiopathologiques évoquées antérieurement: les premières études à l’origine d’une théorie vasculaire de la migraine, impliquaient un processus vasculaire en deux temps avec une ischémie responsable de l’aura migraineuse suivie d’une hyper perfusion responsable de la céphalée; les études ultérieures ont démontré que la céphalée reposait en fait sur des mécanismes neuro-vasculaires et des contr?les centraux plus complexes, impliquant en particulier le système trigéminovasculaire. Actuellement différentes équipes s’intéressent aux signes sensoriels plus généraux qui accompagnent la migraine et qui pourraient témoigner d’une modification globale des perceptions sensorielles et d’une hyperalgésie diffuse, liées à des phénomènes de sensibilisation centrale.      

Physiologie de la douleur et de l’hyperalgésie ou de la nociception à la contagion émotionnelle de la douleur

The intensity of a pain does not simply reflect the severity of the injury that caused it, but also depends very much on the individual’s history. Therefore, clinical pain is also largely the expression of neural plasticity associated with peripheral and central sensitization leading to hyperalgesia, allodynia and persistent, spontaneous pain.Although opioids are recognized as unsurpassed analgesics for moderate to severe pain, for more than a century, experimental and clinical studies have reported that the administration of exogenous opioids not only produces analgesia but also induces long-term hypersensitivity to pain, in the form of prolonged hyperalgesia after an injury which is capable of facilitating the development of chronic pain. Like exogenous opioids, endogenous opioids released during situations of stress induce a latent hypersensitivity to pain that may emerge in the form of more severe pain on subsequent injuries. The hypersensitivity to pain induced by opioids is associated with a more general hypersensitivity affecting the emotional sphere, for example in terms of anxiety.The consequences of hypersensitivity to pain cannot be managed using analgesics alone but require specific antisensitisation strategies, such as NMDA receptor antagonists, nitrous oxide, nefopam and nutrition low in polyamines.     

Les mécanismes de la conscience

Understanding mechanisms of consciousness is a neuroscientific challenge with potential important medical applications. Mechanisms of conscious state should be distinguished from those of conscious access. Regarding conscious state, arousal is a necessary condition for consciousness but it is not a sufficient one. A network of frontal and parietal heteromodal associative areas is also implicated in the emergence of awareness. The same network is necessary for conscious access to given information by the subject as well. Our understanding of consciousness mechanisms allows us to identify, prognosticate and stimulate reappearance of consciousness in a non-conscious patient.