• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Étude des mécanismes de coordination des activités rythmiques locomotrices et sympathiques au sein d’un réseau spinal activé par l’acétylcholine chez le rat nouveau-né / Coordinating mechanisms of locomotor and sympathetic rhythmic activities in a cholinergic-activated spinal network in the newborn rat.

Sourioux, Mélissa 15 December 2017 (has links)
La locomotion, comme toute autre forme d'activité physique, mobilise le système nerveux autonome pour faire face à la demande physiologique croissante. Ces réponses autonomes impliquent un couplage entre les activités motrices sympathiques et somatiques. De manière intéressante, à la fois les réseaux locomoteurs spinaux, ainsi que les neurones préganglionnaires sympathiques intermédiolatéraux (IMLs) sont les cibles d’une modulation par le système cholinergique propriospinal. Dans ce contexte, le but de mon travail doctoral a été d'étudier le rôle du système cholinergique propriospinal dans la coordination entre ces deux systèmes. En utilisant une préparation de moelle épinière de rat nouveau-né isolée in vitro, nous avons montré que l’acétylcholine pourrait permettre un couplage entre les réseaux locomoteurs et sympathiques via l’activation de récepteurs muscariniques. En effet, l'oxotrémorine, un agoniste non-sélectif de ces récepteurs, induit une activité rythmique lente bloquée par des antagonistes des récepteurs muscariniques M1, M2, M3 et M4. De plus, l’oxotrémorine permet de révéler des capacités rythmogènes endogènes de la moelle épinière thoracique. Nous avons observé que les motoneurones thoraciques étaient rythmiquement actifs à la fois durant des épisodes de locomotion fictive et lors de l’application d'oxotrémorine. A l’inverse, les IMLs présentaient une activité rythmique uniquement en présence d'oxotrémorine. Cette étude fournit ainsi de nouveaux éléments concernant les processus neuronaux à l'origine du couplage entre les systèmes somatiques et sympathiques. Nous proposons ici que ces mécanismes de synchronisation sont réalisés en partie via un réseau intraspinal pouvant être activé conditionnellement par le système cholinergique propriospinal. / Locomotion, as any other forms of physical activity, mobilizes the autonomic nervous system to match the increasing physiological demand. These autonomic responses mostly rely on the coupling between sympathetic and somatic motor activities. The propriospinal cholinergic system plays an important role in the control of locomotor networks, and several lines of evidences suggest that it may also activate sympathetic preganglionic neurons from the intermediolateral nucleus (IMLs). The aim of my doctoral thesis was to investigate the role of the cholinergic propriospinal system in the coordination between these two systems. Using the in vitro isolated spinal cord from new born rat, we showed that application of acetylcholine synchronized the locomotor and sympathetic networks, via the activation of muscarinic receptors. Indeed, the non-selective agonist oxotremorine induced slow rhythmic activity blocked by M1, M2, M3 and M4 muscarinic receptor antagonists. In addition, oxotremorine revealed endogenous rhythmogenic capabilities of the thoracic segments. This slow oscillatory activity propagated from thoracic ventral roots to lumbar ones, but not the reverse. We observed that thoracic MNs were rhythmically activated during both locomotorlike activity and oxotremorine-induced rhythm. In contrast, IMLs were rhythmically activated solely in the presence of oxotremorine. This study provides new light on the origin of the coupling between the somatic and the sympathetic systems. We propose that synchronizing mechanisms are achieved in part by an intraspinal network which may be activated under the control of the cholinergic propriospinal system.
2

Νευροφυσιολογική μελέτη διαταραχών του αυτονόμου νευρικού συστήματος σε ασθενείς με επιληψία και η σχέση αυτών με τον τύπο της επιληψίας και την αντιεπιληπτική αγωγή

Σύρρου, Βασιλική Χ. 11 January 2010 (has links)
- / Our purpose was to assess the function of fast somatic nerve fibres, the sympathetic sudomotor system and the function of parasympathetic heart con-trol in patients with partial or generalized seizures, receiving various therapeu-tic regimes, by means of clinical routine neurophysiology. We studied 73 pati-ents (mean age 37,7±12,9 years) and 73 matched healthy controls by clinical and electrophysiological examinations. To assess the function of fast somatic nerve fibres we studied the motor conduction of the peroneal nerve (distal latency, amplitude of action potential, conduction velocity) and the sensory conduction of the ulnar and sural nerves (amplitude of action potential, conduction velocity) in all patients and controls. To assess the sympathetic sudomotor system we studied the sympathetic skin response (SSR) elicited in the hand and foot by electrical and magnetic stimulation. The electrical stimulation applied in all patients and controls but the magnetic stimulation applied in 61 patients and 72 contols (exepted pati-ents and controls wich had something metallic in their body such as surgical clips, pace-maker, metallic valve). To assess the function of parasympathetic heart contol all the patients and the controls were subjected to a battery of three cardiovascular tests: a) heart rate variability during six deep breaths/min [algorithm:(max-min)R-R Interval x 100/mean R-R Interval] b) Valsava maneuver (ratio of the shortest RR interval during phase II to the longest RR interval in phase IV) c) heart rate response to standing up(ratio 30th beat/15th beat). Compared to controls, patients showed a significant abnormality of motor (prolongation of distal latency) and sensory (slowing of ulnar conduction velo-city, reduction of amplitude of sural action potential) conduction. Reason and duration of epilepsy, type and frequency of seizyre and polytherapy didn’t ap-pear to have a negative effect on motor or sensory conduction. Particular antiepileptic drugs, oxcarbazepine, phenytoin, topiramate, lebetiracetam, ap-peared to have a negative effect on sensory conduction. Clinical sings of neu-ropathy were disclosed in 13,7% of patients, while at least one abnormal sen-sory parameter was evident in 11%. In the patient group as opposed to the control group, there was a latency prolongation of sympathetic skin response recorded in hand and foot to elec-trical and magnetic stimulation. At least one SSR abnormality was shown in 28 (38,3%) patients and 9 (12,3%) of these had absent SSR from the hand or/and the food with electrical or/and magnetic stimulation. Reason & duration of epi-lepsy, type, frequency & age at onset of seizure, time from last seizure and po-lytherapy didn’t appear to have a negative effect on sympathetic sudomotor function. Particular antiepileptic drugs, topiramate and phenytoin, appeared to have a negative effect on sympathetic sudomotor function. Finally, the patient group showed significantly difference in all parasympa-thetic parameters studied compared to controls. Overall, 42,2% of patients had abnormal measurement in at least one of these parameters and [algorithm:(max-min)R-R Interval x 100/mean R-R Interval] was the most fre-quently abnormal one (31,5% of patients). Reason & duration of epilepsy, fre-quency, type & age at onset of seizure, time from last seizure and polytherapy didn’t appear to have a negative effect. Particular antiepileptic drugs, oxcarba-zepine and phenytoin appeared to have a negative effect on fuction of para-sympathetic heart control. Overall, 50 of the 73 patients had abnormal measurement in at least one of all parameters wich we studied. Our results suggested that simple neurophysiological tests, suitable for screening purposes, were able to demomstrate abnormalities of the fast so-matic fibers in peripheral nerves, of the sympathetic sudomotor system and of the parasympathetic heart control.

Page generated in 0.0735 seconds