PMID: 233499Jan 1, 1978

Differential beta-adrenergic sensitivity of atrial tissue assessed by chronotropic and inotropic responses to several sympathomimetic amines

Acta Physiologica Latino Americana
M T MarquezP Aramendía


The relative inotropic and chronotropic activity of epinephrine, norepinephrine, isoproterenol, dopamine, dobutamine and ethylephrine was studied on isolated rat atria at 31 C. Dose-response curves were expressed as a percentage of the maximum response. Both atria were used for testing chronotropic effects. Inotropic dose-response curves were performed on left atria driven at 1 Hz, 1.6 Hz, 2.8 Hz and 6.6 Hz. Epinephrine and norepinephrine had a greater chronotropic action than their inotropic one throughout the range of stimulation employed. Their pD2-values changed from 8.12 +/- 0.06 and 8.05 +/- 0.05 to 7.19 +/- 0.03 and 7.14 +/- 0.05, respectively. Isoproterenol, dopamine and ethylephrine produced the same degree of chronotropic and inotropic stimulation. Dobutamine exerted the same effect on heart rate and developed tension at 1 Hz. pD2-values for dobutamine were significantly lower (p less than 0.01, p less than 0.001, p less than 0.001) when the frequency of stimulation was increased to 1.6, 2.8 and 6.6 Hz. These findings may be due to the influence of the negative staircase phenomenon, the temperature and the distribution of beta 1 and beta 2 receptors.

Related Concepts

Dose-Response Relationship, Drug
Right Atrial Structure
Pulse Rate
Myocardial Contraction
Norepinephrine Receptors
Beta-adrenergic receptor
Sympathomimetic Effect

Related Feeds

Adrenergic Receptors: Trafficking

Adrenergic receptor trafficking is an active physiological process where adrenergic receptors are relocated from one region of the cell to another or from one type of cell to another. Discover the latest research on adrenergic receptor trafficking here.

Related Papers

Acta Physiologica Latino Americana
M T MarquezP Aramendía
Acta Physiologica Latino Americana
M T MarquezP Aramendía
Acta Physiologica Et Pharmacologica Latinoamericana : Organo De La Asociación Latinoamericana De Ciencias Fisiológicas Y De La Asociación Latinoamericana De Farmacología
S Neira, M Penna
© 2021 Meta ULC. All rights reserved