[THE ROLE OF ALPHA1-ADRENORECEPRORS FOR ACTIVITY OF THE HEART IN HUMANS AND ANIMALS. PART 1 (REVIEW)]

Area of Science:

• Cardiology
• Molecular Biology
• Pharmacology

Background:

• Alpha 1-adrenoceptors (AR) are crucial in cardiovascular regulation.
• Understanding their cardiac localization and subtypes is key to cardiac function.
• Previous research has indicated varied roles for alpha 1-AR in the heart.

Purpose of the Study:

• To review the localization and concentration of alpha 1-AR in cardiac tissues.
• To elucidate the functional effects of alpha 1-AR activation on the heart.
• To explore the molecular mechanisms and signaling pathways underlying these effects.

Main Methods:

• Literature review of existing studies on alpha 1-AR in the heart.
• Analysis of data on alpha 1-AR subtypes (A, B, D) expression in different species.
• Examination of signaling cascades involving G-proteins, enzymes, and ion channels.

Main Results:

• Alpha 1-AR are found in cardiac plasma and nuclear membranes.
• Activation of alpha 1-AR leads to inotropic, luzitropic, chronotropic, and arrhythmogenic effects.
• Specific subtypes (A and B) are predominant in human and mouse myocardium, while all three are in rat myocardium.

Conclusions:

• Alpha 1-AR play a significant role in modulating cardiac electrophysiology and contractility.
• The diverse effects are mediated by complex signaling pathways involving Gq/Gi proteins and downstream effectors.
• Alpha 1-AR exhibit stability against desensitization, supporting their sustained trophic functions in the heart.