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Communication Dans Un Congrès Année : 2005

Neuromuscular junction and factors influencing the duration of botulinum toxin action.

Résumé

Laboratoire de Neurobiologie Cellulaire et Moléculaire, Centre National de la Recherche Scientifique, Gif sur Yvette 91198 cedex, France. The local injection of botulinal neurotoxins (BoNTs) into adult skeletal muscles of animals and humans blocks quantal acetylcholine release, resulting in muscle paralysis. Although a marked atrophy of skeletal muscle occurs during paralysis, there is no evident damage of motor nerve terminals. The duration of neuromuscular blockade depends upon: i) BoNT serotype; ii) dose used; and iii) animal species. Higher doses are needed to paralyze amphibian, versus mammalian, skeletal muscles. According to their duration of action, BoNTs can be classified into three groups: long-lasting (BoNT/A and BoNT/C), intermediate (BoNT/B and BoNT/F), and short-lasting (BoNT/E). In mammals, neuromuscular blockade is not permanent, as functional recovery returns within a few weeks to months. It is still unclear why the recovery-time in rodents is shorter than in humans after BoNTs exposure. In mammals muscle inactivity following a single injection of BoNT/A, /C, /D or /F elicits, within 3-5 days, a nerve outgrowth or sprouting along intramuscular axons at the nodes of Ranvier (nodal sprouting), and at motor nerve terminals (terminal sprouting) of the neuromuscular junction. The Progression of events leading to the first nerve-muscle contacts, and differentiation of new endplates after BoNTs exposure is a remarkable demonstration of synaptic plasticity. Throughout this period, important communications occur between the synaptic partners involving diverse signaling molecules, and synaptic proteins. Our studies were supported in part by grants (#026065093, #0334046004) from the Direction des Systèmes de Forces et de la Prospective.
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Dates et versions

hal-00109761 , version 1 (25-10-2006)

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  • HAL Id : hal-00109761 , version 1

Citer

Jordi Molgó. Neuromuscular junction and factors influencing the duration of botulinum toxin action.. International Conference 2005 - Basic and Therapeutic aspects of Botulinum and Tetanus toxins. June 23-25, 2005, Denver, Colorado, United States. ⟨hal-00109761⟩

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