Mechanoreceptors of the rabbit duodenum.

A preparation is described which allowed the investigation of single-unit afferent activity in non-myelinated mesenteric nerves in urethane-anaesthetized rabbits. Three classes of mechanoreceptors were isolated and were located in the muscularis externa (n = 17), the serosa (n = 5) and the mesentery (n = 2). Intraluminal perfusion of chemical solutions containing glucose and hypertonic saline caused increased movement in the loop and also excited mechanoreceptors. No specific chemoreceptors were identified. The results demonstrate that duodenal mechanoreceptors with non-myelinated axons in the rabbit are indirectly sensitive to the chemical composition of duodenal chyme.