β3 -AR and the vertebrate heart: a comparative view

Area of Science:

• Cardiovascular Physiology
• Comparative Endocrinology
• Molecular Pharmacology

Background:

• Beta-1 (β1) and beta-2 (β2) adrenergic receptors (ARs) are known regulators of cardiac function.
• Emerging research highlights the role of beta-3 (β3)-ARs in catecholamine (CA)-dependent cardiac control.
• Understanding β3-ARs is vital for potential therapeutic applications in human cardiovascular diseases.

Purpose of the Study:

• To comparatively analyze literature data on β3-ARs in mammals, teleosts (fish), and amphibians.
• To highlight similarities and differences in β3-AR structure, ligand activity, function, and signaling pathways across vertebrate classes.
• To offer new perspectives on the biological significance of β3-ARs in cardiac control and plasticity.

Main Methods:

• Literature review and comparative analysis of existing research on β3-ARs.
• Examination of structural, functional, and signaling data from mammalian, fish, and amphibian studies.
• Focus on the role of endothelium-endocardium (EE), Gi/0 proteins, and nitric oxide (NO) signaling.

Main Results:

• β3-ARs are structurally related to mammalian β1-ARs in fish.
• Functional β3-ARs are present in the cardiac tissue of teleosts and amphibians.
• Activation of β3-ARs in non-mammals negatively modulates cardiac inotropic performance via EE, Gi/0, and NO pathways, similar to mammals.

Conclusions:

• Cardiac β3-ARs exhibit conserved functional roles and signaling mechanisms across diverse vertebrate groups.
• Comparative analysis reveals both uniformity and diversity in β3-ARs, providing insights into their evolutionary context.
• Further research on β3-ARs can elucidate their broader role in cardiac regulation and functional adaptation.