Rev Neurol France
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The neurological spectrum of Borrelia burgdorferi infections is still enlarging. We review epidemiological, pathological and serological data of Lyme disease. The course of the disease is divided in three stages: stage 1 during the first month is characterised by erythema chronicum migrans and associated manifestations; stage 2 includes not only the classical European meningoradiculitis but also less specific neurological symptoms: isolated lymphocytic meningitis with an acute or even relapsing course, apparently idiopathic facial palsy, neuritis of other cranial nerves, polyneuritis cranialis, Argyll-Robertson sign, peripheral nerve involvement, acute transverse myelitis, severe encephalitis, myositis. ⋯ High doses of penicillin can halt the disease, sometimes induce spectacular regression of symptoms or sometimes be inefficient; ceftriaxone could be a more powerful therapy. Similarities between syphilis and Borreliosis are multiple: both of these spirochetes contain plasmids, can be transmitted through the placenta and progress for many years through successive stages, with multiorgan symptoms, including parenchymatous and vascular lesions of the central nervous system. Borrelia burgdorferi is the new great imitator.
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Review Comparative Study
[Role of the ventrobasal complex of the thalamus in nociception and pain: data obtained in the normal rat and in a model of clinical pain].
Recent anatomical, electrophysiological, neuropharmacological and behavioural studies have provided new elements for the understanding of the role of the thalamus in nociceptive and pain mechanism. Data presented here demonstrate that the thalamic ventrobasal complex (VB), which receives direct afferents from the spinothalamic tract in the rat and monkey, plays a role in the sensory-discriminatory component of pain in these two species. Apart from the electrophysiological aspect, we discuss the effects of analgesic compounds on neuronal responses observed at this level and modifications in a nociceptive reaction threshold after lesions of this structure in the non-anesthetized freely moving animal. ⋯ Spinal tracts transmitting messages from these joints appear to differ (at least in part) from those transmitting nociceptive messages in the normal rat. Finally, at similar doses, morphine is much more effective in these animals than in the normal rat. Results of these studies show that nociception and clinical pain are not always exactly dependent on the same systems.
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Due to the combination of multidisciplinary studies, the last fifteen years have seen a major step forward in our knowledge of nociception. At the peripheral level the role of A delta and C polymodal cutaneous nociceptors is relatively well demonstrated in animal as well as in man. The activation of these nociceptors probably results from both direct effects of the stimulus and indirect effects, mediated by the release of various chemicals. ⋯ Descending influences are exerted from the periaqueductal gray matter and the ventromedial medulla (mainly the nucleus raphe magnus). They are sustained by serotoninergic and noradrenergic mechanisms and they involve to a lesser extent the endogenous opioids. The physiological function of these descending systems is still sharply discussed.