Role of tachykinin and neurokinin receptors in the regulation of ovine omasal contractions

► Cyclic contraction of the omasum is vagal cholinergic nerve-independent. ► All mRNA of neurokinin receptor subtypes were expressed in the omausm. ► Among tachykinins, neurokinin A induced most potent contraction of omasal muscles. ► NKA-induced and neurogenic contractions were inhibited by NK-2 receptor antagonist. ► NKA and NK-2 receptor seems primary regulators of omasal contractions.