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1991 Fiscal Year Final Research Report Summary

Estrogen and Hypothalamic Cell Activity : Developmental Effects and Regional Differences.

Research Project

Project/Area Number 01480131
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 環境生理学(含体力医学・栄養生理学)
Research InstitutionHirosaki University

Principal Investigator

SAKUMA Yasuo  Hirosaki Univ. Sch. Med. Professor, 医学部, 教授 (70094307)

Co-Investigator(Kenkyū-buntansha) TAKEO Teruko  Hirosaki Univ. Sch. Med. Research Associate, 医学部, 助手 (20113813)
HOSHINA Yuko  Hirosaki Univ. Sch. Med. Assistant Professor, 医学部, 講師 (50091632)
SUGA Sechiko  Hirosaki Univ. Sch. Med. Assistant Professor, 医学部, 講師 (80003408)
Project Period (FY) 1989 – 1991
KeywordsLordosis reflex / Estrogen / Ventral tegmental area / Antidromic activation / Medial preoptic area / Ventromedial hypothalamus / Testosterone / Unit activity
Research Abstract

Lordosis reflex is an estrogen-dependent, essential component of the female rat sexual behavior. We examined electrical stimulation effects of the POA on lordosis in the free-moving, estrogen- and progesterone-treated ovariectomized 'rats, which were deprived of septal efferents of the POA by neural transections and compared with those of the ventral tegmental area (VTA). The cut reduced the amount of estrogen needed to elicit maximal lordosis. In spite of the removal of septal inhibition, stimulation of the transected POA caused a prompt and strong suppression of lordosis in response to male mounts with a threshold at 30muA. The optimal frequency was at 50-100 Hz. Lordosis performance returned promptly to the prestimulation level after the termination of current application. The rapid time course d
istinguished the effect from that in the non-deafferented animals, , which occurred slowly and persisted. VTA stimulation at 30muA and 75-125 Hz was as effective as stimulation of the transe … More cted POA to cause a rapid and strong suppression of lordosis. No aversive response accompanied the blockade of lordosis form the POA or VTA. Electrical stimulation of both structures specifically blocked lordosis, without disrupting the proceptive components of the female-sexual behavior. Thus, the POA is an independent and separate entity in the Inhibitory mechanism of lordosis. The exaggerated effect of electrical stimulation in the deafferented animals may result from a desruption of facilitative circuitry-for this reflex by the transection.
In 683 POA neurons, VTA stimulation in urethane-anesthetized rats caused antidromic activation at latencies ranging 1.643.7 ms. Stimulus threshold was as low as 60muA in 106 rats under light urethane anaesthesia. Effects of estrogen, given 5-8 days prior to the recording in a 5-mm Silastic capsule, were compared within each animal group, which consisted of 38 female rats ovariectomized as adults (n=278, n, number of cells), 38 male rats castrated on the day of birth (day 1, NC males) (n=181), and 30 female rats given 1.25 mg testosterone on day 5 and ovariectomized as adults (TP females) (n=224). estrogen significantly increased the antidromic activation threshold in the ovariectomized females (P<0.02, Mann-Whitney U test) and in the NC males (P<0.04). In the former, the prolonged refractory period (P<0.02) and antidromic spike latency (P<0.002) were also detected. In the TP females, no parameter was affected by estrogen. Thus estrogen depressed the excitability of the POA axons in animals which had not been exposed to testosterone during the development.
In animals under urethane anesthesia, antidromic spike latency (range : 2-40 ms) and stimulus threshold (100-1, 500muA) were determined for 371 neurons in the ventromedial hypothalamic nucleus (VMN) following electrical stimulation of the mid-brain central grey In 10 intact (number of neurons, n=71) and 29 orchidectomized male rats, which received either no treatment (10 rats, n=75), testosterone propionate (5 rats, n=75), estradiol benzoate (8 rats, n=77) or dehydrotestosterone (6 rats, n=73). Orchidectomy significantly decreased antidromic activation thresholds. Either hormone was effective to raise the mean threshold to values comparable to that in the intact males. Frequency histograms of the threshold showed that dehydrotestosterone achieved this effects by decreasing the number of cells at a low threshold range, whereas the action of estrogen was not on this fraction of cells. The histogram for the testosterone-treated animals was similar to that in the intact males. The results suggest that different subgroups of VMN neurons with specific sensitivity to metabolites of testosterone project to the central grey, and may govern different aspects of endocrine or affective controls.
Long-term recordings up to 4 days were made from neurons in the POA in free-moving female rats during the copulatory encounter with males by microwire electrodes. We found (1) neurons specifically respond to vaginal stimulation by the male partner, and (2) those with a brief increase in their activity prior to the display of lordosis. Less

  • Research Products

    (47 results)

All Other

All Publications (47 results)

  • [Publications] Hasegawa,Takeshi: "Sexual differentiation of oestrogen sensitivity of the rat forebrain efferent neurones." Journal of Physiology.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takeo,Teruko: "Suppression of the lordosis reflex of female rats by efferents of the medial preoptic area." Journal of Neuroscience.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Suga,Sechiko: "Differential effects of testosterone metabolites on male rat medial hypothalamic neurons with axons to mid-brain central grey." Journal of Endocrinology.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Hasegawa,Takeshi: "Interruption of the lordosis reflex of female rats by ventral midbrain stimulation." Physiology & Behavior.50. 1033-1038 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Hasegawa,Naoya: "Differential refulation of estrogen-dependent sexual development of rat brain by growth factors." Neuroscience Letters.123. 183-186 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Hoshina,Yuko: "Changes in photically evoked blink reflex during sleep and wakefulness." Japanese Journal of Ophthalmology.35. 182-187 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Akaishi,Takao: "Estrogen-induced modulation of hypothalamic osmoregulation in female rats." American Jurnal of Physilogy.258. R924-R929 (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Hasegawa,Takeshi: "Estrogen-induced suppression of female rat forebrain neurons with axons to ventral midbrain." Neuroscience Letters.119. 171-174 (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takahashi,Yasuo: "Brain aromatase activity and behavioral consequences in the male rat treated in utero with 4-hydroxy-androstenedione." Endocrinologia Japonica.36. 29-36 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Akaishi,Takao: "Effects of estrogen on hypothalamic paraventricular neurons in tissue slices from ovariectomized rats." Biomedical Research.10. 149-155 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "神経ペプチドと性行動の調節" バイオメディカ. 6(13). 31-37 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "女性の性周期" 臨床神経科学. 9. 503-505 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "神経内分泌と行動:性行動" 臨床神経科学. 8. 412-415 (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "エストロジェン感受性脳内神経回路の多様性" ホルモンと臨床. 38. 983-988 (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "神経内分泌細胞の電気生理学的特徴" 神経研究の進歩. 33. 31-37 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "性ホルモンによる脳の性分化" 新潟医学会雑誌. 103. 625-631 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "性欲“脳代謝とその異常"" 代謝. 26. 111-115 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Sakuma,Yasuo: "Brain control of female sexual behavior.In Yokoyama,A.(ed.),Brain-Control of Reproductive System." Japan Science Societies Press,Tokyo/Springer-Verlag,Berlin.,

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "神経科学レビュ-5 「性行動の調節機構」" 医学書院, 335 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 佐久間 康夫: "佐藤 昌康編 ブレインサイエンスIII「性的に異なった脳内神経回路の成立過程」" 朝倉書店, 90-103 (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Sakuma,Yasuo: "Y.Sagara and K.Seto,Ed.,“Pheromones and Reproduction"" Parthenon Publishing,Carnforth,Lancs,UK., 179-188 (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Akaishi, T.: "Effects of Estrogen on Hypothalamic Paraventricular Neurons in Tissue Slices from Ovariectomized Rats." Biomedical Research. 10. 149-155 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Akaishi, T.: "Estrogen-Induced Modulation of Hypothalamic Osmoregulation in Female Rats." American Journal of Physiology. 258. R924-R929 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Akaishi, T.: "Estrogen-Induced Modulation of Hypothalamic Osmoregulation in Female Rats." Japanese Journal of Physiology. 39. S270 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takahashi, Y.: "Brain Aromatase Activity and Behavioral Consequences in the Male Rat Treated in Utero with 4-Hydroxy-androstenedione." Endocrinologia Japonica. 36. 29-36 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takahashi, Y.: "Effects of in utero Treatment with 4-Hydroxy-androstenedione on Hypothalamic Aromatase Activity and Differentiation of Sexually Dimorphic Behavior in the Rat." Neuroscience Research Supplement. 9. S117 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Estrogen-Induced Suppression of Female Rat Forebrain Neurons with Axons to Ventral Midbrain." Neuroscience Letters. 119. 171-174 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Saito, H.: "Facilitatory and Inhibitory Central Nervous Mechanisms for the Control of Female Rat Reproductive Behavior." "Pheromones and Reproduction". Parthenon, Carnforth. 179-188 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, N.: "Differential Regulation of Estrogen-Dependent Sexual Development of Rat Brain by Growth Factors." Neuroscience Letters. 123. 183-186 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, N.: "Growth Factor-Mediated Sexual Differentiation of Reproductive Behavior and Ovarian Functions in the Rat." Japanese Journal of Physiology. 39. S269 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sakuma, Y.: "Involvement of Neurotrophic Factors in the Sexhormone Dependent Masculinization of the Rat Brain." Neuroendocrinology. 52(Suppl. 1). 5-6 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Interruption of the Lordosis Reflex of Female Rats by Ventral Midbrain Stimulation." Physiology & Behavior. 50. 1033-1038 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sakuma, Y.: "Interruption of Lordosis Behavior from Electrical Stimulation of the Female Rat Ventral Tegmental Area." Proceedings of the International Union of Physiological Sciences. 17. 310 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Interruption of Lordosis Reflex from Electrical Stimulation of the Ventral Tegmental Area in the Ovariectomized Female Rats." Neuroscience Research. 11. S15 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hoshina, Y.: "Changes in Photically Evoked Blink Reflex During Sleep and Wakefulness." Japanese Journal of Ophthalmology. 35. 182-187 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takeo, T.: "Suppression of the Lordosis Reflex of Female Rats by Efferents of the Medial Preoptic Area." Journal of Neuroscience.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takeo, T.: "Preoptic Efferents Suppress the Display of Lordosis Reflex in the Female Rat." Neuroscience Research. 16. S148 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sakuma, Y.: "Suppression of Lordosis Reflex in the Female Rats by Electrical Stimulation of the Forebrain and Ventral mid-brain." Journal of Physiology. 446. 84 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Sexual Differentiation of Oestrogen Sensitivity of the Rat Forebrain Efferent Neurones." Journal of Physiology.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Effects of Neonatal Gonadectomy upon the Estrogen Sensitivity of Medial Preoptic Neurons Projecting to the Ventral Tegmental Area." Japanese Journal of Physiology. 39. S119 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Influences of Neonatal Gonadectomy or Androgen Exposure on Sexual Differentiation of Estrogen Sensitivity in Rat Medial Preoptic Neurons." Japanese Journal of Physiology. 40. S157 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sakuma, Y.: "Sex Steroids and Hypothalamic Cell Activity : Developmental Effects and Regional Differences." The Neuroendocrine Hypothalamus. British Neuroendocrine Group-Physiological societies Symposium (Invited Lecture), Babraham, U. K.BS5 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sakuma, Y.: "Brain Control of Female Sexual Behavior." "Brain-Control of Reproductive System". Japan Science Societies Press, Tokyo/Springer-Verlag, Berlin.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Suga, S.: "Differential Effects of Testosterone Metabolites on Male Rat Medial Hypothalamic Neurons with Axons to mid-brain Central Grey." Journal of Endocrinology.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Electrophysiological Approach for the Identification of the Hypophysiotropic Luteinizing Hormone Releasing Hormone Neurons." Neuroscience Research. 14. S101 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hasegawa, T.: "Estrous Cycle-correlated Alternations in Single Unit Activity of Medial Preoptic Neurons Recorded from Freely-moving Female Rats." Japanese Journal of Physiology. 41. S201 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Hoshina, Y.: "Inhibition of the Lordosis Reflex of Female Rats by Septal Axons Descending through the Preoptic Area." Brain Research.

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1993-03-16  

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