CHRNA3 Human

The CHRNA3 gene encodes the alpha-3 subunit of the nicotinic acetylcholine receptor. This receptor is a pentameric complex, typically composed of both alpha and beta subunits. The alpha-3 subunit contains characteristic adjacent cysteine residues, which are essential for its function. When acetylcholine binds to the receptor, it induces a conformational change that opens an ion-conducting channel across the plasma membrane .

Nicotinic acetylcholine receptors, including those containing the alpha-3 subunit, are involved in the transmission of signals across synapses. These receptors are found in various parts of the nervous system, including the autonomic ganglia, where they mediate fast synaptic transmission. The activation of these receptors by acetylcholine leads to the influx of cations, such as sodium and calcium, which depolarizes the neuron and propagates the signal .

Polymorphisms in the CHRNA3 gene have been associated with several health conditions. Notably, variations in this gene are linked to an increased risk of smoking initiation and susceptibility to lung cancer. This association is due to the role of nicotinic receptors in the reward pathways of the brain, which are implicated in addictive behaviors .

Additionally, the CHRNA3 gene has been associated with bladder dysfunction, autonomic disorders, and impaired pupillary reflex. These conditions highlight the importance of the alpha-3 subunit in the proper functioning of the autonomic nervous system .

Research into the CHRNA3 gene and its encoded protein continues to be of significant interest. Understanding the structure and function of this receptor subunit can provide insights into the development of targeted therapies for conditions related to its dysfunction. For instance, modulating the activity of alpha-3-containing nicotinic receptors could potentially lead to new treatments for nicotine addiction and certain autonomic disorders .