Tone of LES is maintained by
Acetylcholine and tachykinins are involved in the LOS contraction acting through acetylcholine M3 and tachykinin NK2 receptors. Nitric oxide can also be involved in the regulation of LOS contraction. Ref: guyton and hall textbook of medical physiology 12 edition page number:443,444,445
Acetyl choline
Dopamine
Serotonine
VIP
G.I.T