Proceedings of The Physiological Society

University of Central Lancashire (2002) J Physiol 543P, S227


Structural and functional aspects of mechanoreceptor endings in rat colon

Jonathan R. Coldwell, Stuart M. Brierley, Nicole J. Cooper and L. Ashley Blackshaw

Nerve-Gut Research Laboratory, Royal Adelaide Hospital and Department of Physiology, Adelaide University, SA 5000, Australia

Pelvic and lumbar splanchnic afferents may play an important role in mediating both noxious and non-noxious sensation from the colon. These afferents have been categorized previously by electrophysiological studies as three populations, according to the location of their receptive fields: mucosal afferents, muscular afferents and serosal afferents (Lynn & Blackshaw, 1999). No information is available on the structure of any of these endings. We aimed to correlate the function and structure of serosal afferent endings using a combination of electrophysiological recording and a modified anterograde labelling technique. The distal colon with attached inferior mesenteric ganglion (IMG) and lumbar splanchnic nerves (LSN) were removed from fifteen humanely killed rats and perfused in an organ bath with modified Krebs solution. The LSN was drawn into a second paraffin-filled chamber and small strands of fibres placed onto an electrode for recording. Receptive fields were located by mechanical stimulation. The recorded strand was treated with a 1

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