Anxiolytic-like effects of milk proteins

Milk varieties and specific proteins exhibit anxiolytic-like actions in mice and rats exposed to several tests, the most prominent being the elevated plus-maze. Administrations of α_s1-casein, its 91–100 (α-casozepine), 91–97, 91–93, and 91–92 fragments, the 60–69 fragment of β-casein, lactoferrin, β-lactotensin, wheylin-1, wheylin-2, and α-lactalbumin have been reported to increase open arm exploration relative to enclosed arm exploration. Anxiolytic-like actions have also been described for 91–93 and 91–92 fragments of α_s1-casein, wheylin-1, α-lactalbumin, and lactoferrin in the open-field. Some effects appear to be mediated by the GABA_A receptor complex, since antagonists mitigated the anxiolytic-like actions of α_s1-casein, the 91–92 fragment of α_s1-casein, and wheylin-1. Other neurotransmitters purported to affect such behaviors include 5HT, dopamine, and neurotensin. Further research is needed to identify their neuropharmacological actions.