Achykinins are active peptides which excite neurons, evoke behavioral responses, are potent vasodilators and secretagogues, and contract (directly or indirectly) many smooth muscles.TAC1 is an abbreviation for protachykinin 1, a protein that is encoded by the TAC1 gene, which is responsible for 4 products of the tachykinin peptide hormone family: substance P, neurokinin A, and the related peptides, neuropeptideK and neuropeptide . Tachykinin peptides are important in the mediation of many physiological and pathological processes including inflammation, pain, migraine headache and allergy induced asthma.