1. Intracellular movements of fluorescently labeled synaptic vesicles in frog motor nerve terminals during nerve stimulation.
- Author
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Betz WJ, Bewick GS, and Ridge RM
- Subjects
- Animals, Electric Stimulation, Fluorescent Dyes, Microscopy, Fluorescence, Movement, Rana pipiens, Motor Neurons physiology, Nerve Endings physiology, Synaptic Vesicles physiology
- Abstract
We stained synaptic vesicles in frog motor nerve terminals with FM1-43 and studied changes in the shape and position of vesicle clusters during nerve stimulation. Each stained vesicle cluster appeared as a fluorescent spot. During repetitive nerve stimulation the spots gradually dimmed, most without changing shape or position. Occasionally, however, a spot moved, appearing in some cases to stream toward and coalesce with a neighboring spot. This suggests the existence of translocation mechanisms that can actively move vesicles in a coordinated fashion between vesicle clusters. Within single clusters, we saw no signs of such directed vesicle movements. Fluorescent spots in terminals viewed from the side with a confocal microscope did not shrink toward the presynaptic membrane during nerve stimulation, but dimmed uniformly. This suggests that vesicles continuously mix within a cluster during destaining and provides no evidence of active vesicle translocators within single vesicle clusters for moving vesicles to the presynaptic membrane.
- Published
- 1992
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