TY - JOUR
T1 - Influence of a long-term powdered diet on the social interaction test and dopaminergic systems in mice
AU - Niijima-Yaoita, Fukie
AU - Tsuchiya, Masahiro
AU - Saito, Hiroko
AU - Nagasawa, Yuka
AU - Murai, Shigeo
AU - Arai, Yuichiro
AU - Nakagawasai, Osamu
AU - Nemoto, Wataru
AU - Tadano, Takeshi
AU - Tan-No, Koichi
N1 - Funding Information:
This work was supported by a Grant-in-Aid for Young Scientists (B) (MEXT KAKENHI Grant No. 24700433 ) from the Japan Society for the Promotion of Science and a Matching Fund Subsidy for Private Universities from the Ministry of Education, Culture, Sports, Science and Technology Japan (2010–2014). The authors acknowledge the excellent technical assistance of Ms. Misaki Suzuki, Ms. Kaori Ishikawa, Ms. Misato Sato, Mr. Koichi Chiba, and Ms. Mayuko Nakamura.
PY - 2013
Y1 - 2013
N2 - It is well known that the characteristics of mastication are important for the maintenance of our physical well-being. In this study, to assess the importance of the effects of food hardness during mastication, we investigated whether a long-term powdered diet might cause changes in emotional behavior tests, including spontaneous locomotor activity and social interaction (SI) tests, and the dopaminergic system of the frontal cortex and hippocampus in mice. Mice fed a powdered diet for 17 weeks from weaning were compared with mice fed a standard diet (control). The dopamine turnover and expression of dopamine receptors mRNA in the frontal cortex were also evaluated. Spontaneous locomotor activity, SI time and dopamine turnover of the frontal cortex were increased in powdered diet-fed mice. On the other hand, the expression of dopamine-4 (D4) receptors mRNA in the frontal cortex was decreased in powdered diet-fed mice. Moreover, we examined the effect of PD168077, a selective D4 agonist, on the increased SI time in powdered diet-fed mice. Treatment with PD168077 decreased the SI time. These results suggest that the masticatory dysfunction induced by long-term powdered diet feeding may cause the increased SI time and the changes in the dopaminergic system, especially dopamine D4 receptor subtype in the frontal cortex.
AB - It is well known that the characteristics of mastication are important for the maintenance of our physical well-being. In this study, to assess the importance of the effects of food hardness during mastication, we investigated whether a long-term powdered diet might cause changes in emotional behavior tests, including spontaneous locomotor activity and social interaction (SI) tests, and the dopaminergic system of the frontal cortex and hippocampus in mice. Mice fed a powdered diet for 17 weeks from weaning were compared with mice fed a standard diet (control). The dopamine turnover and expression of dopamine receptors mRNA in the frontal cortex were also evaluated. Spontaneous locomotor activity, SI time and dopamine turnover of the frontal cortex were increased in powdered diet-fed mice. On the other hand, the expression of dopamine-4 (D4) receptors mRNA in the frontal cortex was decreased in powdered diet-fed mice. Moreover, we examined the effect of PD168077, a selective D4 agonist, on the increased SI time in powdered diet-fed mice. Treatment with PD168077 decreased the SI time. These results suggest that the masticatory dysfunction induced by long-term powdered diet feeding may cause the increased SI time and the changes in the dopaminergic system, especially dopamine D4 receptor subtype in the frontal cortex.
KW - Dopamine
KW - Frontal cortex
KW - Locomotor activity
KW - Mastication
KW - Powdered diet
KW - Social interaction test
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U2 - 10.1016/j.neuint.2013.07.004
DO - 10.1016/j.neuint.2013.07.004
M3 - Article
C2 - 23871718
AN - SCOPUS:84880978636
VL - 63
SP - 309
EP - 315
JO - Neurochemistry International
JF - Neurochemistry International
SN - 0197-0186
IS - 4
ER -