OHMentholAnother example of pungency in foods, similar to the hot spicy
pungency of chili and of black pepper, but not the same, is the pun-
gency of mustard, horseradish, and wasabi. Associated with this
particular perceptual quality of hotness is a family of molecules, the
isothiocyanates, characterized by a particular configuration of sulfur,
carbon, and nitrogen atoms. Allyl isothiocyanate is found in mustard
and horseradish.
One,Allyl isothiocyanateAnother type of ionotropic Ca** channel, called TRPA1, is activated
by the binding of isothiocyanates. Activation of the TRPA1 receptors
results in neural signals from a different set of cells than would be the
case with capsaicin and TRPV1, and this is associated with a qualita-
tively different experience of hotness and pungency.
TRP-type channel proteins turn out to be all over the place in the
body: in the mouth, where they are associated with the perception
of spicy and pungent hotness and with minty coolness; within the
skin, where they are involved in the perception of temperature and
also of touch and pain (see Chapter 16); and elsewhere in the nervous
system, where they are likely involved in neural signaling in yet to be