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A STUDY ON THE MECHANISM UNDERLYING MILK EJECTION BURSTS OF OXYTOCIN CELLS.

Research Project

Project/Area Number 07680869
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Neuroscience in general
Research InstitutionFukui Medical School

Principal Investigator

NEGORO Hideo  Fukui Medical School, Vice-President, 副学長 (90018903)

Co-Investigator(Kenkyū-buntansha) HONDA Kazumasa  Fukui Medical School, Physiology, Assistant-professor, 医学部, 助教授 (50143946)
Project Period (FY) 1995 – 1996
Project Status Completed (Fiscal Year 1996)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1996: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1995: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywordsoxytocin / milk ejectin reflex / burst discharge / synchronization / afferent pathway / summatin mechanism / gate
Research Abstract

In order to study the neural mechanisms to generate burst activities of oxytocin neurones during suckling in lactating rats, the following three studies were made :
(1) the effect of midbrain-hemitransection on amplitudes and time courses of milk ejection bursts of oxytocin neurones in lactating rats.
Extracellular recordings of the electrical activity of oxytocin neurones were made from the supraoptic nuclei of lactating rats, and the milk-ejection bursts were investigated in the midbrain-hemitransected rats. Of the burst recorded from oxytocin neurones on the lesioned side, the amplitude was smaller, the onset time was later and the burst span was shorter than those recorded on the non-lesion-ed side. These results indicated that the amplitude and time course of the burst of oxytocin neurones mainly depend on suckling information from the nipples on their opposite side.
(2) the effects of unilateral suckling on milk ejection bursts of oxytocin neurones in intact rats.
When application of pups was limited to the nipples on either the same side or the side opposite to the oxytocine neurone recorded, the burst amplitude was significantly lower than during bilateral suckling. Furthermore, the burst amplitude was significantly lower during ipsilateral suckling than during contralateral suckling. The finding indicates that the burst amplitude mainly depends on the amount of afferent suckling signals arising from the nipplies on the side opposite to the reocording side.
(3) the effect of interhemispheric sections of the hypothalamus on milk-ejection bursts of supraoptic oxytocin neurones.
Extensive interhemispheric sectioning did not abolish the burst of oxytocin neurones during bilateral and contralateral suckling but reduced the number of oxytocine neurones that showed the burst during ipsilateral suckling. The result suggest that there are two separate gate and summation mechanisms on each side of the hypothalamus.

Report

(3 results)
  • 1996 Annual Research Report   Final Research Report Summary
  • 1995 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] Wang, Y-F., Negoro, H., Honda, K.: "Effects of hemitransection of the medbrain on milk-ejection burst of oxytocin neurones in lactating rat." J. Endocrinology. 144. 463-470 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Wang, Y-F., Negoro, H., Honda, K.: "Amplitudes and time courses of milk ejection bursts of oxytocin neurons in the midbrain-hemitransected lactating rat." Brain Research. 719. 203-206 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Wang, Y-F., Negoro, H., Honda, K.: "Milk Ejection Bursts of Supraoptic Oxytocin Neurones during Bilateral and Unilateral Suckling in the rat." J. Neuroendocrinol.8. 427-431 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Y.-F.Wang, H.Negoro, K.Honda: "Effects of hemitransection of the medbrain on milk-ejection burst of oxytocin neurones in lactating rat." Journal of Endocrinology. 144. 463-470 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Y.-F.Wang, H.Negoro, K.Honda: "Amplitudes and time courses of milk ejection bursts of oxytocin neurons in the midbrain-hemitransected lactating rat." Brain Research. 719. 203-206 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Y.-F.Wang, H.Negoro, K.Honda: "Milk Ejection Bursts of Supraoptic Oxytocin Neurones during Bilateral and Unilateral Suckling in the Rat." Journal of Neuroendocrinology. 8. 427-431 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Wang,Y-F.,Negoro,H.,Honda,K.: "Amplitudes and time courses of milk ejection bursts of oxytocin neurons in the midbrain-hemitransected lactating rat." Brain Research. 719. 203-206 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] Wang,Y-F.,Negoro,H.,Honda,K.: "Milk Ejection Bursts of Supraoptic Oxytocin Neurones during Bilateral and Unilateral Suckling in the rat." J.Neuroendocrinol.8. 427-431 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] Wang,Y-F.,Negoro,H.,Honda,K.: "Effects of hemitransection of the medbrain on milk-ejection burst of oxytocin neurones in lactating rat." Journal of Endocrinology. 144. 463-470 (1995)

    • Related Report
      1995 Annual Research Report

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Published: 1995-04-01   Modified: 2016-04-21  

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