| Project/Area Number |
15390629
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Surgical dentistry
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| Research Institution | Asahi University School of Dentistry |
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Principal Investigator |
NAKASHIMA Kiyohito Asahi University School of Dentistry, 歯学部, 助教授 (30102122)
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| Co-Investigator(Kenkyū-buntansha) |
SAKO Noritaka Asahi University School of Dentistry, 歯学部, 助教授 (90243154)
KATSUKAWA Hideo Asahi University School of Dentistry, 歯学部, 助手 (00076051)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥10,400,000 (Direct Cost: ¥10,400,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥6,200,000 (Direct Cost: ¥6,200,000)
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| Keywords | zinc deficiency / rats / mice / gustatory dysfunction / salt preference / behavioral response / conditioned taste aversion / hormonal imbalance / ホルモン調節 / 味覚神経応答 / ナトリウム代謝 / アルドステロン / 飲水行動 / 味覚障害 / アポトーシス |
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| Research Abstract |
In this study, we investigated the effects of Zn deficiency on taste sensitivity and various salts intakes by behavioral, electrophysiological and biochemical studies in rodents. 1.Behavioral studies using the 48-h two-bottle tests showed enhanced preference for NaCl in Zn deficient rats (ZnD-rats). The enhanced preference for NaCl in ZnD-rats was not observed when 10 min two-bottle test was used. The 48-h two-bottle test in ZnD-rats also showed that transection of the taste nerves did not affect the NaCl preference. The conditioned taste aversion tests showed similar generalization patterns between control and ZnD-rats for each of the four basic taste substances. In mice, the 48-h two-bottle test and lick rate test showed that aversiveness for CaCl_2 was larger in ZnD-mice than in the control. Changes in the behavioral responses to CaCl_2 were recovered by feeding the ZnD-mice with control diet for 1 week. The results suggest that taste may not play a role for enhanced NaCl preference in ZnD-rats, and that ZnD-rats have the ability to discriminate the basic taste qualities. The results also suggest a possibility that zinc deficiency may alter the taste-guided drinking behavior of CaCl_2 in mice. 2.Electrophysiological recordings of the chorda tympani nerve responses in rats showed no significant differences in concentration-response relationships for various taste stimuli between the two groups, suggesting that Zn-deficiency has negligible effects on taste sensitivities for the taste stimuli. 3.Serum Na levels in the ZnD-rats tended to be lower and more variable than those of control and pair-fed rats. A daily excretion of urinary Na tended to increase in the ZnD-rats. In the serum of ZnD-rats, angiotensin II and Ca levels significantly decreased, whereas aldosterone levels significantly increased. The results suggest that the disorder of sodium metabolism with upregulation of aldosterone is involved in Zn deficiency.
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