Abstract
The net influx of metaraminol into sympathetic nerve endings of rat ventricle slices as well as the resultant efflux of norepinephrine (NE) is a function of the metaraminol concentration in the incubation fluid and reaches a maximum at a concentration of about 400 ng/ml. Amphetamine in low concentrations (0.4 ) reduces the efflux of NE and the uptake of metaraminol to the same extent, indicating that amphetamine interferes with the metaraminol-induced release of NE only by reducing the uptake of the drug. In contrast, desipramine reduces the efflux of NE to a much greater extent than it blocks the uptake of metaraminol. These results indicate that desipramine interferes with the metaraminol-induced release of NE in two ways: 1) by reducing the uptake of metaraminol and 2) by interfering with the action of metaraminol within the neuron, possibly by an action on the granules.
Footnotes
- Received September 22, 1969.
- Accepted January 27, 1970.
- © 1970, by The Williams & Wilkins Company
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