2022 Fiscal Year Final Research Report
Identification of inhibitory neural circuitry underlying male ejaculatory behavior in the female brain
| Project/Area Number |
20K06471
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 42040:Laboratory animal science-related
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| Research Institution | The University of Tokushima |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 外側傍巨大細胞網様核 / アンドロゲン / 性差 |
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| Outline of Final Research Achievements |
The behavioral sex differences clearly exist in many animals including rodents. Adult female mouse shows lower levels of male-typical sexual behavior even after treatment with large doses of androgen. Here we report that the lateral nucleus paragigantocellularis (LPGi) serves a vital function in inhibiting motivational and consummatory aspects of male sexual motor patterns in female mice. Discrete excitotoxic or serotonergic lesions placed in the middle subregion of the LPGi accelerated the expression of mount and intromissive pattern in female mice and some of these animals had ability to achieve ejaculatory pattern. We next aimed to identify the neural circuits of serotonergic neurons in the middle subregion of the LPGi. Anterograde tracing using Cre-dependent herpes simplex virus revealed projections of serotonergic neurons to various brain regions including the frontal cortex, the preoptic area, the paraventricular nucleus and the motor neurons in the lumbosacral spinal cord.
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| Free Research Field |
実験動物学
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| Academic Significance and Societal Importance of the Research Achievements |
元来は、脳の雌性化は受動的プロセスで、周生期にアンドロゲンが作用しないと、基本型である雌脳としてそのまま発達すると考えられていた。本研究により、１）雌の脳内にも射精に至るまでの全ての雄型性行動パターンを発現させる神経機構が潜在的には存在していること、２）LPGi中間亜核を起点としたセロトニン作動性の抑制型神経回路が発達していることが、雌性が異性行動を示さない要因であることを明らかにした。即ち、雌脳への性分化の過程は、雄型性行動に対する抑制型神経回路を積極的に発達させる能動的プロセスであることを提唱し、脳の性差研究に新たな知見をもたらすものであると考える。
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