Local vs Central Nervous System control of Hindgut Motility

Motility is a critical function of the gastrointestinal (GI) system governed by multiple neurogenic and myogenic processes. Several overlapping mechanisms have evolved for its regular operation including modulation by the Central Nervous System (CNS), Enteric Nervous System (ENS), and intrinsic pacemaker cells. These processes remain poorly understood since mammalian species offer limited accessibility. Crayfish provides an accessible ex vivo model to study the interplay between CNS regulation and neurochemical control of GI motor patterns. In this talk, we will discuss the effects of CNS denervation and exogenously applied serotonin (5-HT) on hindgut motility. Multiscale measurements showed motility parameters mostly comprised seconds-scale waves, that remained stable throughout 90 minutes of control conditions. Eliminating CNS innervation reduced wave power and movement coordination, but did not affect frequency or wave direction. Subsequent application of 5-HT increased wave power and directional switching, but failed to restore synchronized movement, indicating that exogenous serotonin does not fully compensate for the loss of CNS regulation. Our model provides a multiscale analysis framework to connect CNS and interrelated neurochemistry to GI motor dynamics.