Synaptogenesis is a complex process involving several steps that ultimately results in the matching of neurotransmitters released from the presynaptic nerve terminals with the appropriate receptors expressed by the postsynaptic neuron. In this thesis, I examined one step in the process of synaptogenesis, the expression of postsynaptic receptors. Cultured neonatal rat nodose neurons are a good model for these studies; in vivo, nodose neurons do not form synaptic contacts, but interestingly, when they develop alone in dissociated tissue culture most neurons express nicotinic acetylcholine receptors (nAChRs) and form de novo cholinergic synapses. First, I investigated the factors that influence nAChR expression by nodose neurons. I determined that in vivo, only 40% of nodose neurons have functional nAChRs, however, when grown alone in culture more than 80% express nAChRs and the majority have ACh current densities comparable to those on neurons that normally received cholinergic innervation. I found that ganglionic satellite cells control nAChR expression by nodose neurons, whereas trophic factors, such as nerve growth factor (NGF) and neurotrophin-3 (NT-3), can up-regulate ACh current density in the absence of the satellite cell influence. Second, as several different genes encode nAChRs, I was interested in determining the nAChR transcripts expressed by nodose neurons; mRNA for $ alpha3, alpha5, alpha7, beta2, beta3$ and $ beta4$ were detected by RNase protection assay. In addition, these changes in differentiated properties suggested that nodose neurons were developing a phenotype resembling that of autonomic neurons. Consequently, for comparison, I examined nAChR expression by rat sympathetic neurons, both at the functional and molecular level. Superior cervical ganglion (SCG) neurons express five nAChR transcripts: $ alpha3, alpha5, alpha7, beta2$ and $ beta4.$ To address which subunits are incorporated into the functional receptor, I used both electrophysiolog
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.39557 |
| Date | January 1992 |
| Creators | Mandelzys, Allan |
| Contributors | Cooper, E. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001319273, proquestno: NN87706, Theses scanned by UMI/ProQuest. |
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