| Project/Area Number |
06670075
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Niigata University School of Medicine |
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Principal Investigator |
AKAISHI Takao Department of Physiology, Niigata University School of Medicine, Associate professor, 医学部, 助教授 (70018951)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Body water control mechanism / Circulation control mechnism / Estrogen / Supraoptic nucleus / AV3V / Vasopressin / Electrophysiology / Rat / 体液浸透圧 / 圧受容器 / 性線 / 視床下部 |
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| Research Abstract |
Relationships between female gonadal endocrine functions and regulatory mechanisms for body water and circulation were electrophysiologically examined in vivo and in vitro in the ovariectomized rat. In 1994, the effect of hyperosmolality (300,320 mosmol/kgH_2O) and angiotensin II (A II,10^<-8> and 10^<-6> M) was tested on supraoptic vasopressin and AV3V (anteroventral 3rd ventricle) neurons in brain slice preparations obtained from ovariectomized (OVX) rats with or without chronic treatment of estradiol-17b(E2). In the OVX_+E2 rat, the neuronal responses following hyperosmotic-and All-stimuli were significantly smaller than that of the control OVX rat. These data suggest a dynamic relationship between the ovarian endocrine function and the central mechanisms regulating a release of vasopressin in the female rat. As the next step of experiment, effects of E2 and E2 plus progesterone (EP) on the baroreceptor-induced response in the supraoptic vasopressin neurons were examined in ovariect
… More
omized (OVX) female rats. Neuronal responses induced by pharmacologically caused pressor or depressor responses, were inhibited in the E2 treated animals. Progesterone had no effect. These results suggest that estrogen modifies the baroreceptor induced responses in supraoptic vasopressin neurons in the OVX female rat. In 1995, in in vitro experiment using brain slice preparations, sensitivity of hypothalamic vasopressinneurons to noradrenaline which is identified to be a final common transmitter from the medura to the vasopress in neurons in the hypothalamus of the OVX and OVX_+E2 rats. Neuronal responses were clearly smaller in the OVX_+E2 than that in the OVX animals.
These results consistently suggest the existence of dynamic relationship between ovarian endocrine functionand central regulatory mechanisms for body water and circulation in the female subject. Sensitivity of those neurons to neuropeptide Y (NPY) which is speculated to modify the common neurotransmitter mechanism at the level of postsynaptic sites on vasopressin neurons, is also investigating now. Less
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