The arylalkylamine-N-acetyltransferase (AANAT) acetylates dopamine in the digestive tract of goldfish: A role in intestinal motility

► The enzymes AANAT1 and HIOMT show daily rhythms in goldfish retina. ► The AANAT1 activity, but not the HIOMT, is functional in goldfish gut and liver. ► The AANAT1 activity regulates the content of dopamine and N-acetyldopamine in liver. ► Dopamine, an alternative AANAT1 substrate, regulates gut motility.