Contrasting effects of digitalis and dobutamine on baroreflex sympathetic control in normal humans.
Circulation
; 84(3): 1118-29, 1991 Sep.
Article
in En
| MEDLINE
| ID: mdl-1884443
ABSTRACT
BACKGROUND:
Digitalis glycosides augment cardiopulmonary baroreceptor mechanisms in animals. This could result from inotropic actions or from direct sensitization of cardiac mechanoreceptors. METHODS ANDRESULTS:
To determine if digitalis has similar actions in humans and to evaluate the mechanisms involved, we measured muscle sympathetic nerve activity (MSNA; microneurography) during unloading of cardiopulmonary baroreceptors with incremental lower body negative pressure (LBNP; 0 to -15 mm Hg) and during the cold pressor test in 22 normal subjects (age 22 +/- 1 year, mean +/- SEM). Arterial and central venous pressures, heart rate, and MSNA were measured during LBNP before and after intravenous digitalis (Cedilanid 0.02 ng/kg, n = 8), dobutamine (2.8 +/- 0.5 micrograms/kg/min, n = 8), or placebo (n = 6). Digitalis and dobutamine produced similar increases in baseline mean arterial pressure and decreases in central venous pressure and MSNA. LBNP produced similar decreases in central venous pressure in all groups before and after drug administration. The MSNA responses to LBNP were markedly potentiated by digitalis but not by dobutamine or placebo.CONCLUSIONS:
Digitalis did not alter responses to the cold pressor test. Thus, digitalis selectively potentiated cardiopulmonary baroreflex regulation of sympathetic neural responses in normal humans, whereas dobutamine (another positive inotropic agent) did not produce this effect. We conclude that digitalis augments cardiopulmonary baroreflex control of sympathetic activity, probably by direct baroreceptor sensitization.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pressoreceptors
/
Reflex
/
Sympathetic Nervous System
/
Blood Pressure
/
Deslanoside
/
Dobutamine
Type of study:
Clinical_trials
Limits:
Adult
/
Humans
/
Male
Language:
En
Journal:
Circulation
Year:
1991
Document type:
Article
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA