Therapeutic potential of allosteric modulators for the treatment of
gastrointestinal motility disorders.
Abstract
Gastrointestinal motility is tightly regulated by the enteric nervous
system (ENS). Disruption of coordinated ENS activity can result in
dysmotility. Pharmacological treatment options for dysmotility include
targeting of G protein-coupled receptors (GPCRs) expressed by neurons of
the ENS. Current GPCR-targeting drugs for motility disorders bind to the
highly conserved endogenous ligand binding site and promote
indiscriminate activation or inhibition of the target receptor
throughout the body. This can be associated with significant side-effect
liability and a loss of physiological tone. Allosteric modulators of
GPCRs bind to a distinct site from the endogenous ligand, which is
typically less conserved across multiple receptor subtypes and can
modulate endogenous ligand signalling. Allosteric modulation of GPCRs
that are important for ENS function may provide effective relief from
motility disorders while limiting side-effects. This review will focus
on how allosteric modulators of GPCRs may influence gastrointestinal
motility, using 5-HT, ACh, and opioid receptors as examples.