1996 Fiscal Year Final Research Report Summary
Mechanism of reciprocal control of the autonomic nervous system by VIP-and vasopressin-neurons in the suprachiasmatic nucleus of the hypothalamus
| Project/Area Number |
07670171
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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 |
Pathological medical chemistry
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| Research Institution | Osaka University |
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Principal Investigator |
NAGAI Katsuya Osaka University, Institute for Protein Research, Professor, たんぱく質研究所, 教授 (70029966)
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| Project Period (FY) |
1995 – 1996
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| Keywords | 2-deoxy-D-glucose / hyperglycemia / sympathetic nerve / VIP / vasopressin / somatostatin / receptor / antisense |
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| Research Abstract |
Intracranial injection of 2-deoxy-D-glucose (2DG), an inihibitor of glucose utilization, caused hyperglycemia in rats. In this hyperglycemic response, exitations of sympathetic efferents projected to pancreas, liver and adrenal, increases in plasma concentrations of glucagon and adrenaline, and a suppression of the increase in the plasma insulin concentration are involved. In rats with bilateral lesions of the suprachiasmatic nucleus (SCN) and blind rats the hyperglycemic response to intracranial injection of 2DG was not observed. From these facts we examined the role of neurons containing vasoactive intestinal peptide (VIP) in the SCN in these responses because the VIP-neurons receive retinal neural inputs. Consequently, it was observed that the excitation of sympathetic efferents projected to the adrenal and the hyperglycemia elicited by intracranial injection of 2DG were eliminated by bilateral lesions of the SCN and intracranial injection of VIP rescued these responses. Furthermore, it was observed that inhibition of the expression of VIP in the SCN caused by antisense oligodeoxynucleotide to VIP mRNA eliminated the hyperglycemic response due to intracranial injection of 2DG.These facts indicate that neurons containing VIP in the SCN are involved in the mechanisms of the responses to intracranial injection of 2DG.In the SCN there are neurons containing arginine vasopressin (AVP) and somatostatin (SS). It was also observed that intracranial injection of AVP suppressed and that of an AVP-antagonist enhanced the excitation of the sympathetic activity and hyperlgycemia induced by intracranial injection of 2DG,and it was reported that intracranial injection of SS caused similar effects to those elicited by that of AVP.Whether these functions of AVP and SS derives from neurons containing these neuropeptides in the SCN,and if so what is the mechanism of the reciprocal control of the autonomic nervous system due to these neuropeptides are now under investigation.
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