Autonomic nervous system (ANS)

The **autonomic nervous system** is a major division of the peripheral nervous system responsible for regulating involuntary bodily functions such as heart rate, blood pressure, digestion, and respiratory rate. It consists primarily of two branches—the **sympathetic** and **parasympathetic** divisions—which often have opposing effects on target organs. The sympathetic division prepares the body for "fight-or-flight" responses by increasing cardiac output and redirecting blood flow to muscles. The parasympathetic division promotes "rest-and-digest" activities that conserve energy and facilitate maintenance functions[1][9]. At the molecular level, autonomic signaling occurs via neurotransmitters such as acetylcholine and norepinephrine acting on distinct classes of receptors—primarily **nicotinic**, **muscarinic**, **alpha-,** and **beta-adrenergic receptors**[1][5]. These individual receptor proteins are considered therapeutic targets in various diseases. For example: | Receptor Type | Molecular Classification | Example Drugs | |----------------------|---------------------------------|-------------------| | Nicotinic receptor | Ligand-gated ion channel | Varenicline | | Muscarinic receptor | G protein–coupled receptor | Atropine | | Alpha adrenergic | G protein–coupled receptor | Prazosin | | Beta adrenergic | G protein–coupled receptor | Atenolol | While modulation of overall autonomic tone can be achieved through interventions like renal denervation or baroreflex stimulation[2][3][6], these approaches ultimately act via altering activity at these underlying molecular targets. The term "autonomic nervous system" refers to an entire functional network rather than a discrete molecule or druggable target. Therefore it should not be classified as a canonical therapeutic target itself but rather as an anatomical/physiological entity composed of many individual druggable proteins. If you require structured information about specific molecular targets within the autonomic nervous system—such as muscarinic acetylcholine receptors or beta-adrenoceptors—please specify which one(s) you need detailed data for.

Other names

vegetative nervous systemvisceral nervous system