Afferent nerves not only convey information concerning normal physiology, but also signal disturbed homeostasis and pathophysiological
processes of the different organ systems from the periphery towards the central nervous system. As such, the increased activity or 'sensitization'
of mesenteric afferent nerves has been allocated an important role in the pathophysiology of visceral hypersensitivity and abdominal pain
syndromes.
Mesenteric afferent nerve activity can be measured in vitro in an isolated intestinal segment that is mounted in a purpose-built organ bath and
from which the splanchnic nerve is isolated, allowing researchers to directly assess nerve activity adjacent to the gastrointestinal segment.
Activity can be recorded at baseline in standardized conditions, during distension of the segment or following the addition of pharmacological
compounds delivered intraluminally or serosally. This technique allows the researcher to easily study the effect of drugs targeting the peripheral
nervous system in control specimens; besides, it provides crucial information on how neuronal activity is altered during disease. It should be
noted however that measuring afferent neuronal firing activity only constitutes one relay station in the complex neuronal signaling cascade, and
researchers should bear in mind not to overlook neuronal activity at other levels (e.g., dorsal root ganglia, spinal cord or central nervous system)
in order to fully elucidate the complex neuronal physiology in health and disease.
Commonly used applications include the study of neuronal activity in response to the administration of lipopolysaccharide, and the study of
afferent nerve activity in animal models of irritable bowel syndrome. In a more translational approach, the isolated mouse intestinal segment can
be exposed to colonic supernatants from IBS patients. Furthermore, a modification of this technique has been recently shown to be applicable in
human colonic specimens.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)