Fig. 3 |. Circuits, cells and molecules involved in gut mechanosensation.

a | Extrinsic innervation of the gastrointestinal tract. From the vantage of the central nervous system, vagal, thoracolumbar and lumbosacral pathways innervate distinct regions of the gastrointestinal tract. There are three prevertebral ganglia (PVGs): coeliac, superior mesenteric and inferior mesenteric. b | Constituent cells of mechanosensory circuits in a section of the gut wall. All highlighted cell types are discussed in the main text. c | Mechanosensors in a generic mechanoreceptor. Mechanical force gets transduced by several proteins in the mechanoreceptor, including mechanogated ion channels, integrins and cytoskeletal filaments, among others. Mechanotransducers such as purine receptor P2Y1R and mechanosensitive G-protein-coupled receptors (GPCRs) amplify pathways initiated by mechanosensors. Mechanotransducers carry out their amplification role by activating secondary messengers such as intracellular calcium (Ca²⁺). ICC, interstitial cell of Cajal; IFAN, intestinofugal neuron; IGLE, intraganglionic laminar ending; IMA, intramuscular array; IPAN, intrinsic primary afferent neuron.