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dc.contributor.authorMark, Margo Anneen
dc.date.accessioned2018-05-14T10:14:19Z
dc.date.available2018-05-14T10:14:19Z
dc.date.issued1997
dc.identifier.urihttp://hdl.handle.net/1842/29866
dc.description.abstracten
dc.description.abstractThe functional significance of neuropeptide Y in the rat spinal cord is unclear and there have been no reports of the stimuli needed to produce release of this peptide in vivo. When a peripheral nerve is injured a de novo synthesis of neuropeptide Y occurs in many large and some medium sized dorsal root ganglion neurones. The experiments in this thesis employed the antibody microprobe technique to study both in normal rats and in those with a peripheral mononeuropathy the spinal release of extracellular immunoreactive neuropeptide Y and to determine the origin of such release.en
dc.description.abstractIn the initial experiments, microprobes bearing immobilised antibodies to neuropeptide Y were inserted into the lumbar spinal cord of urethane anaesthetised normal rats. In the absence of peripheral stimuli microprobes detected a high basal presence of immunoreactive NPY throughout the entire dorsal and ventral hom. Electrical stimulation of large diameter afferents of the ipsilateral sciatic nerve and unmyelinated primary afferents did not significantly alter the spinal release of immunoreactive neuropeptide Y in the spinal cord. Transection of the spinal cord at a low thoracic level resulted in increased levels of immunoreactive neuropeptide Y only in the lower ventral horn. The predominant failure of electrical stimulation and of spinalisation to significantly alter the basal levels of immunoreactive neuropeptide Y suggests that the latter results from spontaneous activity in intrinsic neurones.en
dc.description.abstractFor studies of rats with a peripheral mononeuropathy, the model of Bennett & Xie was used. Postoperatively the development of mechanical allodynia and hyperalgesia were assessed and animals used at 10-14 days only ifthey displayed the characteristic behavioural signs associated with this model. Sham experiments were carried out in separate animals as controls for the effect of surgery per se. In sham animals both sides of the lumbar spinal cord showed a significant spinal release of immunoreactive neuropeptide Y throughout the entire dorsal horn. The site of greatest extracellular levels was the superficial dorsal horn. A similar distribution was also found in the neuropathic animal on the side contralateral to the nerve ligation. On the ipsilateral side of the neuropathic rat however there was a further zone of spontaneous release of immunoreactive neuropeptide Y in the mid and lower dorsal horn (approximating to laminae III, IV and V). Additionally, electrical stimulation of large diameter afferents of the ipsilateral sciatic nerve resulted in an increase in the spinal release over the entire dorsal and upper ventral horn. Stimulating both large diameter myelinated afferents and small unmyelinated afferents did not increase release of immunoreactive neuropeptide Y above that observed by stimulating large myelinated fibres alone. Thus, the additional zone of spontaneous release found on the ipsilateral side of the neuropathic rat probably represents spontaneous activity in damaged and/or regenerating primary afferents. This may represent central release of a neuroactive compound by ectopic impulses in such fibres.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2018 Block 18en
dc.relation.isreferencedbyAlready catalogueden
dc.titleSpinal release of immunoreactive neuropeptide Y in rats with a peripheral nerve injuryen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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