Autonomic nerves and perivascular fat: interactive mechanisms

Area of Science:

• Physiology
• Vascular Biology
• Adipose Tissue Biology

Background:

• Autonomic innervation of body fat, particularly perivascular adipose tissue (PVAT), is increasingly recognized for its physiological importance.
• Sympathetic neurotransmitters like noradrenaline, ATP, and neuropeptide Y (NPY) interact with receptors on adipocytes.
• Perivascular adipose tissue releases vasoactive substances affecting vascular tone and endothelial function.

Purpose of the Study:

• To review the evidence for autonomic innervation of body fat, focusing on sympathetic neurotransmitter roles.
• To elucidate the interaction between autonomic nerves and PVAT in regulating vascular function.
• To propose a mechanism for how sympathetic neurotransmission influences adipocyte free fatty acid (FFA) content and vascular smooth muscle cells.

Main Methods:

• Literature review of studies on autonomic innervation of body fat and PVAT.
• Analysis of neurotransmitter-receptor interactions (adrenoceptors, purinoceptors, NPY receptors) in adipocytes.
• Examination of the effects of neurotransmitters and adipokines on lipolysis, lipogenesis, and vascular cells.

Main Results:

• Adipocytes express receptors for sympathetic neurotransmitters, enabling modulation of lipolysis and lipogenesis.
• Sympathetic neurotransmitters (noradrenaline, ATP, NPY) and sensory neuropeptide Substance P (SP) influence adipocyte free fatty acid (FFA) content.
• Sympathetic neurotransmission can simultaneously induce vasoconstriction and alter FFA release from PVAT, impacting endothelial function.

Conclusions:

• A strong interaction exists between autonomic nerves and PVAT, crucial for normal vascular function.
• Released FFAs from PVAT can modulate endothelial function, and adipocytes release vasoactive substances.
• The interplay between PVAT and autonomic fibers is a critical, yet understudied, area requiring detailed investigation.