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Metallic taste from electrical and chemical stimulation
Harry T Lawless1, David A Stevens, Kathryn W Chapman
1Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA. htl1@cornell.edu
Chemical Senses
|March 3, 2005
Summary
Metallic taste perception can arise from metal salts, direct metal contact, or electrical stimulation. Two distinct pathways are suggested: one involving retronasal smell and another mediated by oral chemoreceptors.
Area of Science:
- Oral sensory science
- Neuroscience of taste
- Chemosensation
Background:
- Metallic taste is a common complaint, but its underlying mechanisms are not fully understood.
- Previous research suggests a role for retronasal olfaction in some metallic taste perceptions.
Purpose of the Study:
- To investigate the mechanisms of metallic taste perception induced by metal salts, metals, and electrical stimuli.
- To differentiate between olfactory and oral chemosensory contributions to metallic taste.
Main Methods:
- Three experiments were conducted using metal salt solutions, direct metal/bimetallic stimulation, and electrical stimulation via a custom-fabricated device.
- Taste intensity was assessed, and the effect of nasal occlusion on taste perception was evaluated.
Main Results:
- Metallic taste was elicited by ferrous sulfate, metals, and electrical stimuli, with intensity related to voltage and fungiform papilla density.
- Nasal occlusion reduced the intensity of ferrous sulfate-induced taste, but not taste from copper, bimetallic stimuli, or batteries.
- The wording of taste choices influenced the frequency of metallic taste reports.
Conclusions:
- Two distinct mechanisms contribute to metallic taste perception: one linked to retronasal olfaction and another mediated by oral chemoreceptors.
- Electrical and direct metal stimulation of the tongue primarily activate oral chemosensory pathways, independent of smell.