Chemical Senses 9: 341-353,
© 1984
research-article |
A peripheral neural correlate of the human fungiform papillae salty, insipid sensations
Sensory Sciences Center, Graduate School of Biomedical Sciences, University of Texas Houston, TX 77030, USA
Neurophysiological research in several different laboratories has revealed the existence of a Na-, Li-specific peripheral taste system in mammalian herbivores and omnivores, but not carnivores. The presence or absence of this system is readily detectable in the behavior of the animals towards NaCl solutions. It is proposed that the human has an identical system, and that activity within this system is largely, but not entirely, responsible for the elicitation of the human sensations of salty and insipid. Under normal conditions, neurons in this system display high levels of spontaneous activity due largely to salivary Na. Solutions with Na exceeding the salivary Na level will excite the neurons and be perceived as salty. Solutions with Na levels less than that of the saliva will inhibit the neurons and be perceived as insipid. The existence of this system in humans is attested by the fact that human behavior towards NaCl is similar to that seen in the rat and sheep. The stimuli eliciting the human salty sensations are, in most respects, similar to those active in the animal experiments with one exception: KCl, the chloride salt most inactive on animals, elicits a fairly strong salty sensory component. To partially resolve this discordance, it is suggested that the human salty sensation is the result of higher order neural activity that involves another peripheral taste system.