The time course of the spontaneous current spikes produced by the release of the catecholamines from individual vesicles was examined in bovine chromaffin cells by using the carbon filament technique in the amperometric mode. / Frequency histograms of the rise and decay times of the current spikes showed a paucity of very short duration events. Scatterograms of the rise and decay times consistently showed a positive relation, and the best fitted lines intercepted the ordinate (the axis of the decay time) at: 16.06 $ pm$ 6.45 msec (n = 11). / The effect of temperature changes upon the time course of release of content of individual vesicles in chromaffin cells was also examined. The amplitudes of the current spikes did not change significantly, whereas the rise times and the decay times diminished from (23.2 $ pm$ 11.6 to 11.9 $ pm$ 2.7 msec, and from 76.6 $ pm$ 25.4 to 47.3 $ pm$ 9.3 msec respectively) as the temperature was raised from 15$ sp circ$C to 35$ sp circ$C (n = 5). Nevertheless, the Q$ sb{10}$ values of the rise and decay times were surprisingly low. / The experimental findings suggest that in bovine chromaffin cells the duration of the release of content of single vesicles is much longer than in synapses. The results also suggest that this mechanism does not involve processes that are strongly temperature sensitive.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.23431 |
| Date | January 1995 |
| Creators | Walker, Angela |
| Contributors | Glavinovic, M. I. (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 | Master of Science (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001481447, proquestno: MM12287, Theses scanned by UMI/ProQuest. |
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