Quantal nicotinic transmission, from about half of the preganglionic inputs to the perfused rat superior cervical ganglion, was more potent and better sustained when activity was in short, high frequency bursts, rather than in continuous trains, regardless of train frequency. The advantage of short bursts was in producing post-tetanic potentiation, while limiting both depression of synaptic potential amplitude and increases in failure rate that were evident during long trains. Presynaptic bursting was also more effective in suppressing, via muscarinic and non-cholinergic mechanisms, the postganglionic cell afterhyperpolarization. This suppression allowed cells to fire at higher frequencies during bursts of depolarizing current pulses used to simulate nicotinic epsps. Burst patterning of activity was concluded to enhance ganglionic transmission via both pre and postsynaptic mechanisms. Presynaptic conduction block, possibly associated with accumulation of extracellular K$ sp+$, appeared to be partly responsible for the depression of quantal transmitter release during long trains.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75746 |
| Date | January 1987 |
| Creators | Isacoff, Ehud Yeheskel |
| 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: 000570078, proquestno: AAINL46091, Theses scanned by UMI/ProQuest. |
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