Dominant Role of N-Type Ca 2+ Channels in Evoked Release of Norepinephrine from Sympathetic Neurons

Multiple types of calcium channels have been found in neurons, but uncertainty remains about which ones are involved in stimulus-secretion coupling. Two types of calcium channels in rat sympathetic neurons were described, and their relative importance in controlling norepinephrine release was analyz...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 1988-01, Vol.239 (4835), p.57-61
Main Authors: Hirning, Lane D., Fox, Aaron P., McCleskey, Edwin W., Olivera, Baldomero M., Thayer, Stanley A., Miller, Richard J., Tsien, Richard W.
Format: Article
Language:English
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Summary:Multiple types of calcium channels have been found in neurons, but uncertainty remains about which ones are involved in stimulus-secretion coupling. Two types of calcium channels in rat sympathetic neurons were described, and their relative importance in controlling norepinephrine release was analyzed. N-type and L-type calcium channels differed in voltage dependence, unitary barium conductance, and pharmacology. Nitrendipine inhibited activity of L-type channels but not N-type channels. Potassium-evoked norepinephrine release was markedly reduced by cadmium and the conesnail peptide toxin ω- Conus geographus toxin VIA, agents that block both N- and L-type channels, but was little affected by nitrendipine at concentrations that strongly reduce calcium influx, as measured by fura-2. Thus N-type calcium channels play a dominant role in the depolarization-evoked release of norepinephrine.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.2447647