Locomotor recovery in the chronic spinal rat: effects of long-term treatment with a 5-HT2 agonist.
A complete transection of the spinal cord at a low thoracic level induces a paraplegic syndrome that is accompanied by a loss of spinal cord serotonin content. Former experimental data suggest that the central pattern generator for locomotion, located in the lumbar segments of the spinal cord, might be able to generate rhythmic motor outputs (similar to automatic walking under certain circumstances) involving exteroceptive stimulations and activation of serotonergic receptors. In the present study, we investigated the effects of a chronic treatment using a serotonergic agonist, delivered continuously to the sublesionned spinal cord, and its effect on motor function recovery. The data obtained from behavioural, kinematic and electromyographic measurements suggest that the chronic stimulation of 5-HT2 type receptors allows motor function recovery. Behavioural measurements show a clear improvement in motor performances when compared to spinal animals (confirmed by kinematic observations): alternating steps and foot placement is recovered in these animals. However, electromyographic data demonstrate that the pattern of activation of the muscles is only restored partially.
Neurobiologie des Signaux Intercellulaires (NSI), Institut de Biologie Intégrative (IFR 83), Université Pierre et Marie Curie, (CNRS UMR 7101), 7 quai Saint Bernard Boite 002, F-75252 Paris, France.
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D000818:Animals; D004334:Drug Administration Schedule; D004576:Electromyography; D005260:Female; D006614:Hindlimb / Q000294:innervation / Q000502:physiology; D008124:Locomotion / Q000187:drug effects* / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009415:Nerve Net / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010507:Periodicity; D011814:Quipazine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000378:metabolism; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D016896:Treatment Outcome; D014741:Video Recording
D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; D011814:Quipazine