Abstract
To determine the distribution of (Na+ + K+)-ATPase at the sympathetic nerve endings of various organs of the cat, specific [3H]ouabain binding to microsomal preparations of different tissues was measured in either NaCl-treated or 6-hydroxydopamine-treated adult cats. Specific [3H]ouabain binding to microsomal preparations either decreased (salivary glands, heart, nictitating membrane, and vas deferens), increased (brain), or showed no change (kidney and spleen) following administration of 6-hydroxydopamine. The dissociation constants of [3H]ouabain, determined by Scatchard analysis, either decreased (heart and nictitating membrane), increased (salivary glands and vas deferens), or did not change (brain) as a result of the administration of 6-hydroxydopamine. More than 80% of the total number of specific [3H]ouabain binding sites in salivary glands, heart, nictitating membrane, and vas deferens were localized at the sympathetic nerve endings. These results are consistent with the hypothesis that (Na+ + K+)-ATPase located on the heart muscle cell membrane may be a part of the "pharmacological receptors" for ouabain and that the inhibition of (Na+ + K+)-ATPase found on the sympathetic nerve endings of heart muscle may be involved, in part, in the development of cardiac glycoside-induced cardiac arrhythmia.
- Copyright © 1977 by Academic Press, Inc.
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