Although there is as yet no method which measures directly the neuronal release of noradrenaline in humans in vivo, the isotope dilution technique with [3H]noradrenaline has been applied to estimate forearm neuronal noradrenaline release into plasma. Two different equations have been developed for this purpose: one to estimate the spillover of noradrenaline into the venous effluent, and a modified formula (often referred to as the appearance rate) which may reflect more closely changes in the neuronal release of noradrenaline into the synaptic cleft, particularly during interventions that alter forearm blood flow. The present study was performed to compare the effects of two interventions known to exert contrasting actions on neuronal forearm noradrenaline release and forearm blood flow. Intra-arterial infusion of sodium nitroprusside at doses without systemic effect increases forearm blood flow, but not neuronal noradrenaline release. In contrast, lower-body negative pressure at -25 mmHg causes forearm vasoconstriction by stimulating neuronal noradrenaline release. During sodium nitroprusside infusion, forearm noradrenaline spillover increased from 1.1±0.3 to 2.2±1.0 pmol·min-1·100 ml-1 (P < 0.05), whereas the forearm noradrenaline appearance rate was unchanged. Lower-body negative pressure did not affect the forearm noradrenaline spillover rate, but increased the forearm noradrenaline appearance rate from 3.4±0.4 pmol·min-1·100 ml-1 at baseline to 5.0±0.9 pmol·min-1·100 ml-1 (P < 0.05). These results indicate that the noradrenaline appearance rate provides the better approximation of changes in forearm neuronal noradrenaline release in response to stimuli which alter local blood flow.
Skip Nav Destination
Article navigation
Research Article|
October 03 2000
Comparison of two indices for forearm noradrenaline release in humans
Gerard A. RONGEN;
*Division of Cardiology, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada
†Departments of Pharmacology, Toxicology and Internal Medicine, University Hospital St Radboud, 6500 HB Nijmegen, The Netherlands
Correspondence: Dr G. A. Rongen, Department of Pharmacology/Toxicology (233), UMC St Radboud, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands (e-mail [email protected]).
Search for other works by this author on:
Jacques W. M. LENDERS;
Jacques W. M. LENDERS
†Departments of Pharmacology, Toxicology and Internal Medicine, University Hospital St Radboud, 6500 HB Nijmegen, The Netherlands
Search for other works by this author on:
Paul SMITS;
Paul SMITS
†Departments of Pharmacology, Toxicology and Internal Medicine, University Hospital St Radboud, 6500 HB Nijmegen, The Netherlands
Search for other works by this author on:
John S. FLORAS
John S. FLORAS
*Division of Cardiology, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
March 24 2000
Accepted:
June 02 2000
Online ISSN: 1470-8736
Print ISSN: 0143-5221
The Biochemical Society and the Medical Research Society © 2000
2000
Clin Sci (Lond) (2000) 99 (5): 363–369.
Article history
Received:
March 24 2000
Accepted:
June 02 2000
Citation
Gerard A. RONGEN, Jacques W. M. LENDERS, Paul SMITS, John S. FLORAS; Comparison of two indices for forearm noradrenaline release in humans. Clin Sci (Lond) 1 November 2000; 99 (5): 363–369. doi: https://doi.org/10.1042/cs0990363
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Cited By
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() |