Newly discovered tachykinins raise new questions about their peripheral roles and the tachykinin nomenclature.

The tachykinin family has recently been extended by the discovery of a third tachykinin gene encoding previously unknown mammalian tachykinins (hemokinin 1, endokinin A and endokinin B) that have a widespread peripheral distribution and a tachykinin NK(1) receptor selectivity. This and the identification of other tachykinin-like peptides such as C14TKL-1 and virokinin raise many questions about the roles played by tachykinins in peripheral tissues and render terms such as 'neurokinins' and 'SP receptor' inappropriate.