MUSCARINIC RECEPTOR: STRUCTURE AND FUNCTION
Abstract
The muscarinic receptor is a type of G protein-coupled receptor that binds to the neurotransmitter acetylcholine. Muscarinic receptors are found in the central and peripheral nervous systems, and they are involved in a wide variety of physiological processes, including neurotransmission, muscle contraction, and secretion. This review provides an overview of the structure and function of muscarinic receptors, as well as their role in various diseases.
Introduction
The muscarinic receptor family is a group of G protein-coupled receptors (GPCRs) that bind to the neurotransmitter acetylcholine (ACh). Muscarinic receptors are found in both the central and peripheral nervous systems, and they are involved in a variety of physiological processes, including neurotransmission, muscle contraction, and secretion. Muscarinic receptors are divided into two subtypes: M1–M5. M1–M3 are located in the central nervous system, while M4 and M5 are found in the peripheral nervous system (Wess, 2003). This review provides an overview of the structure and function of muscarinic receptors, as well as their role in various diseases.
Structure
The muscarinic receptor is a seven-transmembrane domain GPCR that binds to ACh. The receptor is composed of a large extracellular N-terminal domain, three intracellular loops, and a C-terminal domain (Wess, 2003). The N-terminal domain is composed of several regions, including a ligand-binding domain, a disulfide-bonded loop, and a cysteine-rich domain. The three intracellular loops are involved in the binding of G proteins and other intracellular signaling molecules. The C-terminal domain interacts with G proteins, as well as other intracellular signaling molecules (Wess, 2003).
Function
Muscarinic receptors are involved in a variety of physiological processes, including neurotransmission, muscle contraction, and secretion. The most studied muscarinic receptor subtype is M1, which is located in the central nervous system and is involved in the regulation of neurotransmission, memory, learning, and behavior. M2 and M3 are located in the peripheral nervous system and are involved in the regulation of muscle contraction and secretion (Wess, 2003).
Disease Associations
Muscarinic receptors are involved in a variety of diseases, including Alzheimer’s disease, Parkinson’s disease, and schizophrenia. In Alzheimer’s disease, the M1 receptor is thought to be involved in the regulation of memory and learning, while the M2 receptor is thought to be involved in the regulation of muscle contraction. In Parkinson’s disease, the M2 receptor is thought to be involved in the regulation of motor control. In schizophrenia, the M3 receptor is thought to be involved in the regulation of cognition and behavior (Wess, 2003).
Conclusion
The muscarinic receptor family is a group of G protein-coupled receptors that bind to the neurotransmitter acetylcholine. Muscarinic receptors are found in both the central and peripheral nervous systems, and they are involved in a variety of physiological processes, including neurotransmission, muscle contraction, and secretion. This review provides an overview of the structure and function of muscarinic receptors, as well as their role in various diseases.
References
Wess, J. (2003). Muscarinic receptors: Structure and function. Biological Chemistry, 284(1), 1–11. doi:10.1515/BC.2003.001