Vagal receptors sensitive to lipids in the small intestine of the cat.

In anesthetized cats, the unitary activity of 53 sensory vagal neurons was recorded in nodose ganglia by means of extracellular glass microelectrodes. All the neurons had non-medullated fibres, with conduction velocities ranging from 0.8 to 1.2 m/s. Forty of these cells were stimulated by perfusion of the small intestine with lipids. Two types of receptors were identified: 21 endings were activated by glycerol and short chain lipids, and 19 endings were activated by long chain lipids. These receptors did not respond to either mechanical or osmotic stimulation. The discharge frequency generally increased with the concentration. The short latency suggested that they were located close to the enterocyte. The role of vagal intestinal receptors sensitive to lipids is discussed. Their functional characteristics along with previous experimental data suggest that they may be involved in the regulation of gastric emptying and alimentary behaviour, particularly satiety mechanisms.