Molecular basis for species-specific sensitivity to "hot" chili peppers.
Chili peppers produce the pungent vanilloid compound capsaicin, which offers protection from predatory mammals. Birds are indifferent to the pain-producing effects of capsaicin and therefore serve as vectors for seed dispersal. Here, we determine the molecular basis for this species-specific behavioral response by identifying a domain of the rat vanilloid receptor that confers sensitivity to capsaicin to the normally insensitive chicken ortholog. Like its mammalian counterpart, the chicken receptor is activated by heat or protons, consistent with the fact that both mammals and birds detect noxious heat and experience thermal hypersensitivity. Our findings provide a molecular basis for the ecological phenomenon of directed deterence and suggest that the capacity to detect capsaicin-like inflammatory substances is a recent acquisition of mammalian vanilloid receptors.
Jordt
Sven-Eric
SE
Department of Cellular and Molecular Pharmacology, University of California, San Francisco 94143, USA.
Julius
David
D
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002211:Capsaicin / Q000378:metabolism* / Q000494:pharmacology; D002645:Chickens; D004351:Drug Resistance / Q000235:genetics; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009154:Mutation; D011955:Receptors, Drug / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D013045:Species Specificity
D011955:Receptors, Drug; D002211:Capsaicin