Effect of beta-lactotensin on acute stress and fear memory.
beta-Lactotensin (beta-LT) is a bioactive peptide derived from bovine milk beta-lactoglobulin and is a natural ligand for neurotensin receptors. We examined the effect of beta-LT on restraint stress and fear memory in mice. Mice subjected to acute restraint stress exhibited a decreased number of head-dips and increased head-dip latency compared to non-stressed controls in the hole-board test, reflecting increased stress-induced behaviors. However, prior administration of beta-LT improved the behaviors caused by stress. The anti-stress effect of beta-LT was blocked by levocabastine, a neurotensin receptor subtype 2 (NTR2) antagonist. In the fear-conditioning test, the duration of freezing responses by cued fear conditioning was significantly reduced in mice administered beta-LT compared with control mice. These results suggest that beta-LT has an anti-stress effect and promotes the extinction of fear memory, which may be mediated by NTR2.
Yamauchi
Rena
R
Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan.
Wada
Etsuko
E
Yamada
Daisuke
D
Yoshikawa
Masaaki
M
Wada
Keiji
K
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009842:Oligopeptides / Q000502:physiology*; D018028:Receptors, Neurotensin / Q000819:agonists; D013315:Stress, Psychological / Q000188:drug therapy / Q000378:metabolism*
C490984:Ntsr2 protein, mouse; D009842:Oligopeptides; D018028:Receptors, Neurotensin; C102984:beta-lactotensin