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Title: Origin of descending projections to identified sympathetic preganglionic neurons
Author: Zagon, Aniko
ISNI:       0000 0001 3576 4797
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 1991
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Relatively little is known about the pathways that control the ultimate step in central vasomotor regulatory system, i.e. the sympathetic preganglionic neurons whose cell bodies lie in the thoracic spinal cord. My main aim was see if these cells receive a direct input from the vasomotor areas of the ventral medulla which are considered as the major source of descending sympatho-regulatory influences. Using a combination of anterograde and retrograde tract-tracing and electron microscopy the existence of monosynaptic projections from cells of three regions of the ventral medulla oblongata - ventromedial, ventrolateral-medial and ventrolateral-lateral part - onto identified sympathoadrenal preganglionic neurons were established. In further tract tracing studies the connections of the ventral medulla with other such brain areas was analysed which are also involved in central vasoregulation. My aim was to reach a better understanding about the role of the ventral medulla in vasoregulation via investigating its projection patterns and thus to learn more, however, indirectly, about the possible nature of the medullo-spinal vasoactive links. A direct connection from the ventrolateral medulla oblongata onto cells of the ventromedial medulla; and a monosynaptic projection from cells of the ventromedial medulla onto cells of the thoracic motoneuron-pool were demonstrated in the electron microscope. In light microscopic tract-tracing studies a projection of the ventrolateral medulla oblongata into limbic forebrain structures and a topographically arranged projection of the ventromedial medulla into the thoracic spinal cord were described. The widespread projection pattern of the ventral medulla with low density input into all of its investigated targets suggest that it provides a modulatory input to both higher vasoregulatory regions and the spinal output systems such as the sympathetic preganglionic neurons and thoracic motoneurons.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Physiology