Adenosine receptor

Adenosine receptor refers to a class of purinergic G protein-coupled receptors with adenosine as their endogenous ligand.

Overview

The adenosine receptor is a key component in the adenosine signaling pathway, which plays a crucial role in cellular functions such as energy transfer, signal transduction, and neurotransmission. There are four known types of adenosine receptors in humans: A1, A2A, A2B, and A3. Each type has a unique distribution in the body and a distinct role in physiological processes.

Function

Adenosine receptors are involved in a wide range of physiological processes. They regulate the release of neurotransmitters such as dopamine and glutamate, influence heart rate and contractility, and modulate inflammatory and immune responses.

Types

A1

The A1 receptor has a high affinity for adenosine and is widely distributed in the brain, spinal cord, heart, and fat cells. It inhibits adenylate cyclase activity, reducing cyclic AMP levels and leading to a decrease in neuronal activity.

A2A

The A2A receptor is primarily found in the brain, particularly in the basal ganglia, and in the blood vessels. It stimulates adenylate cyclase activity, increasing cyclic AMP levels and promoting vasodilation and neurotransmitter release.

A2B

The A2B receptor has a low affinity for adenosine and is expressed in the gut, lung, and immune cells. It is involved in the regulation of immune and inflammatory responses.

A3

The A3 receptor is predominantly expressed in the immune and inflammatory cells. It has a role in mediating inflammatory responses and cell proliferation.

Clinical significance

Adenosine receptors are targets for a variety of drugs used in the treatment of conditions such as Parkinson's disease, asthma, and cardiac arrhythmias. They are also being investigated for their potential role in the treatment of conditions such as cancer, inflammation, and neurodegenerative diseases.

See also

• Purinergic receptor
• G protein-coupled receptor
• Adenosine
• Adenylate cyclase
• Cyclic AMP

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