Immunohistochemical studies have shown opioid peptides in sympathetic ganglia and preganglionic neurons. An inhibitory action of opioids has been demonstrated in some central and peripheral synapses. However, a physiological role of endogenous opioids in sympathetic ganglia has not been well characterized. The present study investigated endogenous opioid action in the SCG of the cat. The results obtained show that an endogenous opioid is released from preganglionic axon terminals, in a frequency range that matches the natural activity of sympathetic preganglionic neurons, and inhibits ganglionic transmission by acting on post-synaptic opiate receptors of the $ mu$ and $ delta$ subtypes coupled to PTX-sensitive G protein. The size of the store of the endogenous opioid in the preganglionic axon terminals is small and readily exhaustible. Protein synthesis and axonal transport are required for maintenance of the store. The opioid inhibition is under control of the PKC system. This study provides the first thorough characterization of the properties of an opioid-mediated inhibitory mechanism in a well-defined synapse.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.41800 |
| Date | January 1994 |
| Creators | Zhang, Chunyi |
| Contributors | Polosa, Canio (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: 001397792, proquestno: NN94729, Theses scanned by UMI/ProQuest. |
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