Molecular basis for species-specific sensitivity to "hot" chili peppers

Sven-Eric Jordt ¹, David Julius

⁰Department of Cellular and Molecular Pharmacology, University of California, San Francisco 94143, USA.

Cell +

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February 21, 2002

View abstract on PubMed

Summary

Birds are indifferent to chili pepper

Area Of Science

Molecular biology
Neuroscience
Ecology

Background

Chili peppers produce capsaicin, a pungent compound that deters mammals but not birds.
Birds act as seed dispersal vectors due to their indifference to capsaicin.
The molecular basis for this species-specific response is not fully understood.

Purpose Of The Study

To determine the molecular basis for the differential behavioral response to capsaicin between mammals and birds.
To identify the specific receptor domain responsible for capsaicin sensitivity.

Main Methods

Identified a specific domain within the rat vanilloid receptor.
Transferred this domain to the chicken vanilloid receptor ortholog.
Assessed the functional response of the modified chicken receptor to capsaicin, heat, and protons.

Main Results

A specific domain of the rat vanilloid receptor conferred capsaicin sensitivity to the chicken ortholog.
The modified chicken receptor, like its mammalian counterpart, was activated by heat and protons.
This indicates that birds and mammals share sensitivity to noxious heat and thermal hypersensitivity.

Conclusions

Provides a molecular explanation for the ecological phenomenon of directed deterrence.
Suggests that the ability to detect capsaicin-like inflammatory substances is a recent evolutionary acquisition in mammalian vanilloid receptors.
Highlights the role of specific receptor domains in shaping species-specific sensory perception and ecological interactions.

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