Induction of total insensitivity to capsaicin and hypersensitivity to garlic extract in human by decreased expression of TRPV1

• Published in: Neuroscience letters 2007-01, Vol.411 (2), p.87-91
• Main Authors: Park, Joong Jean, Lee, Jaehee, Kim, Myung Ah, Back, Seung Keun, Hong, Seung Kil, Na, Heung Sik
• Format: Article
• Language: English
• Subjects: Allicin; Allyl Compounds - pharmacology; Analgesics, Non-Narcotic - pharmacology; Biological and medical sciences; Buccal mucosa; Capsaicin; Capsaicin - pharmacology; Dose-Response Relationship, Drug; Female; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - drug effects; Gene Expression Regulation - genetics; Humans; Introns; Middle Aged; Pain Measurement - methods; Point Mutation; Reaction Time; Sequence Analysis, RNA; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Sulfides - pharmacology; Temperature; TRPA1; TRPV Cation Channels - genetics; TRPV Cation Channels - metabolism; TRPV1; Vertebrates: nervous system and sense organs
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2006.10.046

TRPV1 is a cation channel which is activated by temperature (≥42 °C) and capsaicin. In the present study, we found a person with total insensitivity to capsaicin and attempted to unravel its causes. The expression levels of TRPV1 protein and mRNA in the cells of the person's buccal mucosa were less than half of those in a normal subject. Sequential analysis of mRNA and genomic DNA revealed several point mutations mostly in the second intron of the person's TRPV1. Interestingly, the subject showed hypersensitivity to garlic extract, but TRPA1 (allicin receptor) level was normal. These results suggest that the decreased expression of TRPV1 may be related to a functional knock out in capsaicin sensation and hypersensitivity to allicin in humans.