Abstract
Microinjections of ouabain solution were made directly into certain medullary areas, viz., the dorsal nucleus of the vagus and the nucleus of the tractus solitarius, through a stereotaxically implanted cannula-electrode. Various cardiac arrhythmias developed after injection of ouabain into these areas. Bilateral vagotomy and spinal transection at C2 level prevented or abolished these arrhythmias indicating the involvement of both divisions of the autonomic nervous system. The arrhythmia-producing doses of ouabain administered through the dorsal nucleus of the vagus, the nucleus of the tractus solitarius and the femoral vein were 43 ± 11, 36 ± 3 and 116 ± 25 µg, respectively. Besides cardiac arrhythmias, central injection of ouabain also produced respiratory depression. It is suggested that these two medullary areas may be among many possible central sites of action for the cardiotoxic effects of digitalis glycosides.
Footnotes
- Received November 22, 1971.
- Accepted February 7, 1972.
- © 1972 by The Williams & Wilkins Co.
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