Skip main navigation

Cardiac and pulmonary norepinephrine release and removal in the dog.

Originally published Research. 1983;53:688–694

    Norepinephrine extraction and spillover rates were determined in the heart and lungs of anesthetized dogs under resting conditions, during sympathetic stimulation, and during epicardial pacing. The fractional extraction of norepinephrine across the coronary and pulmonary vascular beds was measured from the venoarterial difference in tritiated norepinephrine after infusion of a tracer dose to a steady state level. Cardiac extraction averaged 0.299 +/- 0.03 and pulmonary extraction averaged 0.215 +/- 0.014; extraction was unaffected by sympathetic stimulation or pacing. Norepinephrine spillover from sympathetic nerve terminals in the heart and lungs was measured from the venoarterial difference in endogenous norepinephrine and plasma flow after correction for the extraction component. Cardiac norepinephrine spillover increased linearly with increasing frequency of sympathetic stimulation to 7.44 times resting levels at 2 Hz. During pacing, there was no change in cardiac norepinephrine spillover despite marked changes in heart rate. Norepinephrine spillover was demonstrated under resting conditions in the lung and was greater than observed in the heart. Pulmonary norepinephrine spillover increased with sympathetic stimulation to 4.15 times resting levels at 2 Hz. It is possible to separate the contributions of norepinephrine extraction and spillover to measured venoarterial differences of norepinephrine under physiological conditions in the dog.


    eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.

    Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.