Anxiolytic effect of music depends on ovarian steroid in female mice.

Music is known to be able to elicit emotional changes, including anxiolytic effects. The gonadal steroid hormones estradiol and progesterone have also been reported to play important roles in the modulation of anxiety. In the present study, we examined whether the effect of music on anxiety is related to ovarian steroid in female mice. Behavioral paradigms measuring anxiety were tested in gonadally intact (SHAM) and ovariectomized (OVX) female mice chronically treated with either placebo (OVX/Placebo), 17beta-estradiol (OVX/E), or progesterone (OVX/P). In the elevated plus maze, light-dark transition, and marble burying tests, SHAM and OVX/P mice exposed to music showed less anxiety than those exposed to white noise or silence while OVX/placebo mice did not show these effects at all. OVX/E mice showed the anxiolytic effect of music only in the marble burying test. Furthermore, pretreatment with progesterone's metabolite inhibitor completely prevented the anxiolytic effect of music in behavioral tests, while pretreatment with a progesterone receptor blocker did not prevent the anxiolytic effect of music. These results suggest that exposure to music reduces anxiety levels, and ovarian steroids, mainly progesterone, may be involved in the anxiolytic effect of music observed in female mice.

Exposure to music in the perinatal period enhances learning performance and alters BDNF/TrkB signaling in mice as adults.

Music has been suggested to have a beneficial effect on various types of performance in humans. However, the physiological and molecular mechanism of this effect remains unclear. We examined the effect of music exposure during the perinatal period on learning behavior in adult mice, and measured the levels of brain-derived neurotrophic factor (BDNF) and its receptor, tyrosine kinase receptor B (TrkB), which play critical roles in synaptic plasticity. In addition, we measured the levels of 3-phosphoinositide-dependent protein kinase-1 (PDK1) and mitogen-activated protein kinase (MAPK), downstream targets of two main pathways in BDNF/TrkB signaling. Music-exposed mice completed a maze learning task with fewer errors than the white noise-exposed mice and had lower levels of BDNF and higher levels of TrkB and PDK1 in the cortex. MAPK levels were unchanged. Furthermore, TrkB and PDK1 protein levels in the cortex showed a significant negative correlation with the number of errors on the maze. These results suggest that perinatal exposure of mice to music has an influence on BDNF/TrkB signaling and its intracellular signaling pathway targets, including PDK1, and thus may induce improved learning and memory functions.

Lack of nociceptin receptor alters body temperature during resting period in mice.

The role of nociceptin (NOC) receptor on body core temperature (Tcore) control was examined using NOC receptor knockout mice. In homozygote NOC receptor-knockout, wild-type, and control C57BL/6J and 129/SV mice, Tcore was continuously recorded under 12:12 h light:dark (LD) and conditions of constant darkness (DD). The Tcore values during the resting period were higher in the NOC receptor-knockout mice than in both wild-type and control mice under both LD and DD conditions. Spontaneous activity during the resting period and plasma cortisol levels were not different between the NOC receptor-knockout and control mice. The findings herein indicate that the NOC receptor is involved in the control of Tcore during the resting period and is independent of light, physical activity and/or cortisol regulation.