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A COMPARISON OF THE CARDIAC ACTIONS OF DOPAMINE AND NORADRENALINE IN ANAESTHETIZED DOGS AND GUINEA‐PIG ATRIA
Author(s) -
Einstein Rosemarie,
Barrett A. M.
Publication year - 1977
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1977.tb02614.x
Subject(s) - chronotropic , dopamine , inotrope , medicine , propranolol , endocrinology , haloperidol , chemistry , heart rate , norepinephrine , blood pressure
SUMMARY 1. The positive chronotropic and inotropic actions of dopamine and noradrena‐line have been compared in anaesthetized dogs and isolated guinea‐pig atria. 2. Inotropic activity was measured with a strain‐gauge arch in vagotomized dogs or estimated from max ( d p/ d t) in dogs with denervated hearts. 3. The effects of propranolol and haloperidol on the concentration‐response curves to both amines were studied in isolated atria. 4. In anaesthetized vagotomized dogs noradrenaline was more potent than dopamine but dopamine appeared to have a selective inotropic action, less apparent with noradrenaline. In denervated hearts, doses of noradrenaline and dopamine which caused similar increases in max ( d p /d t) also caused similar increases in heart rate. 5. In isolated atrial preparations, concentrations of dopamine and noradrenaline which produced similar increases in force of contraction also had similar chronotropic effects. 6. Propranolol produced a shift to the right of the concentration‐response curves to both dopamine and noradrenaline but the antagonism of noradrenaline was quantitatively greater. Haloperidol had no effect in concentrations below those found to cause general tissue depression. 7. It is concluded that neither dopamine nor noradrenaline show any real difference in their relative inotropic and chronotropic activities in the absence of autonomic innervation.