Swallowing reflex elicited by water and taste solutions in humans

We investigated whether water and taste solutions are adequate stimuli for elicitation of the swallowing reflex from the pharyngolaryngeal region in humans. Subjects were five healthy males. Small amounts of water and taste solutions were applied to the posterior tongue of the subject as he reclined on a dental chair. The latency between the onset of application of the stimuli and the occurrence of swallowing was measured. Water was a most effective stimulus for elicitation of the swallowing reflex. The stimulatory effect was altered by anions, particularly Cl-, added to the water. Gustatory factors affected the latency of swallowing. The results suggest that humans have water-sensitive receptors in the pharyngolaryngeal region and that these receptors are responsible for initiation of the swallowing reflex by water.