Melatonin Membrane Receptors in the Vascular System: Function, Modulation and Clinical Relevance

Area of Science:

• Vascular Biology
• Endocrinology
• Pharmacology

Background:

• Melatonin (MEL), a hormone regulated by light cycles, exhibits vasoactive properties.
• These properties are mediated by plasma membrane melatonin receptors (MT1/MT2) and ion channels in the vascular system.
• Understanding the distribution and function of these receptors is crucial for vascular health.

Purpose of the Study:

• To systematically review and map the expression of MT1/MT2 receptors across various vascular beds.
• To elucidate the mechanisms of action, modulation factors, and implications of MEL receptors in vascular reactivity.
• To identify gaps in current research regarding MEL receptor function in the vasculature.

Main Methods:

• Comprehensive literature search and analysis of 50 studies.
• Mapping the heterogeneous expression of MT1/MT2 receptors in different vascular layers and beds.
• Synthesizing data on receptor function, modulation, and effects on vascular tone.

Main Results:

• MT1/MT2 receptors are heterogeneously expressed in cerebral, caudal, mesenteric, and coronary vessels, aorta, and pulmonary arteries.
• Receptor expression varies with physiological conditions (age, estrous cycle) and pathologies (hypertension).
• MEL elicits differential effects, including vasoconstriction (via MT1) and vasodilation (via MT2), modulated by ion channels and signaling pathways.

Conclusions:

• Melatonin receptors are widely expressed throughout the vascular system, with diverse functional roles.
• Vascular responses to MEL depend on the specific vascular bed, receptor subtype, and hormone concentration.
• Further research is needed on circadian variations in receptor expression and their impact on vascular function.