Nature Neuroscience
2, 440 - 446 (1999)
doi:10.1038/8107
Regulation of dense core release from neuroendocrine cells revealed by
imaging single exocytic eventsJ. K. Angleson1, 3, A. J. Cochilla1, 3, G. Kilic1, I. Nussinovitch2
& W. J. Betz11
Department of Physiology and Biophysics, University
of Colorado Medical School, 4200 East Ninth, Denver,
CO 80262, USA
2
Department of Anatomy and Cell Biology, The Hebrew
University-Hadassah Medical School, Jerusalem, Israel
3
The first two authors contributed equally to this work.
Correspondence should be addressed to W. J. Betz bill.betz@uchsc.eduUsing FM1-43 fluorescence, we have optically detected single exocytic and
endocytic events in rat pituitary lactotrophs. About fifty discrete fluorescent
spots abruptly appear around the entire surface of a cell bathed in FM1-43
and high-potassium saline. The spots, which also immunostain for prolactin,
reflect the labeling of dense cores as well as membranes of exocytosed secretory
granules. Stained cores are not released, but remain attached to the cell
and are eventually endocytosed. However, in cells exposed to dopamine (or
an analog, bromocriptine), the cores dissolve and are secreted after several
seconds. Solubilization of dense cores is mediated through a reduction in
cytoplasmic cyclic AMP. Thus, the composition of secretions from individual
secretory granules is regulated.
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