| Project/Area Number |
09670076
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | KYUSHU DENTAL COLLEGE |
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Principal Investigator |
INENAGA Kiyotoshi KYUSHU DENTAL COLLEGE,PHYSIOLOGY,PROFESSOR, 歯学部, 教授 (90131903)
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| Co-Investigator(Kenkyū-buntansha) |
HONDA Eiko KYUSHU DENTAL COLLEGE,PHYSIOLOGY,LECTURER, 歯学部, 講師 (00047812)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | Saliva / Drinking / Thirst / Hypertonic / NaCl / Mannitol / Osmoreceptor / Parotid gland / 飲水 / 唾液分泌 / 遺伝性多飲マウス / 口渇 / 唾液腺 / 多飲 / NaCl |
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| Research Abstract |
Increased plasma osmolarity incudes decreased secretion of saliva and mucus and then these decreased secretion causes thirst sensation. However, it is not clear a relationship underlying between central mechanism of body fluid balance and salivary secretion. A pile of recent studies reveal a central control system of water balance in the body, by mainly using a species of rodents. On the other hand, studies concerning to the mechanisms of salivary secretion have been accomplished by using big animals such as human beings, cows, sheep and dogs. The purpose of this study is to address how a central osmoreception is related to salivary secretion, by using rats which is a species that the central mechanism of body fluid balance has been well understood. We observed the time required to eat a certain weight of pellet and a volume of saliva secreted during the food intake. Then we evaluated how these values were changed with treatment of 24 hours dehydration, intraperitoneal injection of hypertonic saline (0.9 % and 5 %) and intracerebroventricular injection of hypertonic solution ( 1M NaCI, 0.9 M mannitol ). The secreted sa? iva was collected from a polyethylene tube which was cannulated to a duct of the parotid gland. The time required to eat a pellet prolonged with the intraperitoneal injection of 5 % NaCI and the intracerebroventricular injection of 1 M NaCI and O.9 M mannitol. The volume of salivary secretion during the period showed no change or increased a little. On the other hand, 24 hours dehydrated rats showed an increased volume and rate of salivary secretion. Taken from these results, it is suggested that acute administration of hypertonic solution activates osmoreceptors in the central nervous system and this activation decreases salivary secretion from the parotid glands. On the other hands, enhancement of salivary secretion after 24 hours dehydration may imply an involvement of several factors such as taste and tactile sense.
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