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Nakamura S, Sasaki T, Uenoyama Y, Inoue N, Nakanishi M, Yamada K, Morishima A, Suzumura R, Kitagawa Y, Morita Y, Ohkura S, Tsukamura H. Raphe glucose-sensing serotonergic neurons stimulate KNDy neurons to enhance LH pulses via 5HT2CR: rat and goat studies. Sci Rep 2024; 14:10190. [PMID: 38702366 PMCID: PMC11068885 DOI: 10.1038/s41598-024-58470-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 03/29/2024] [Indexed: 05/06/2024] Open
Abstract
Dysfunction of central serotonergic neurons is known to cause depressive disorders in humans, who often show reproductive and/or glucose metabolism disorders. This study examined whether dorsal raphe (DR) serotonergic neurons sense high glucose availability to upregulate reproductive function via activating hypothalamic arcuate (ARC) kisspeptin neurons (= KNDy neurons), a dominant stimulator of gonadotropin-releasing hormone (GnRH)/gonadotropin pulses, using female rats and goats. RNA-seq and histological analysis revealed that stimulatory serotonin-2C receptor (5HT2CR) was mainly expressed in the KNDy neurons in female rats. The serotonergic reuptake inhibitor administration into the mediobasal hypothalamus (MBH), including the ARC, significantly blocked glucoprivic suppression of luteinizing hormone (LH) pulses and hyperglycemia induced by intravenous 2-deoxy-D-glucose (2DG) administration in female rats. A local infusion of glucose into the DR significantly increased in vivo serotonin release in the MBH and partly restored LH pulses and hyperglycemia in the 2DG-treated female rats. Furthermore, central administration of serotonin or a 5HT2CR agonist immediately evoked GnRH pulse generator activity, and central 5HT2CR antagonism blocked the serotonin-induced facilitation of GnRH pulse generator activity in ovariectomized goats. These results suggest that DR serotonergic neurons sense high glucose availability to reduce gluconeogenesis and upregulate reproductive function by activating GnRH/LH pulse generator activity in mammals.
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Affiliation(s)
- Sho Nakamura
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Togo-cho, Aichi, 470-0151, Japan
| | - Takuya Sasaki
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Togo-cho, Aichi, 470-0151, Japan
| | - Yoshihisa Uenoyama
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Naoko Inoue
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Marina Nakanishi
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Koki Yamada
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Ai Morishima
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Togo-cho, Aichi, 470-0151, Japan
| | - Reika Suzumura
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Togo-cho, Aichi, 470-0151, Japan
| | - Yuri Kitagawa
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Togo-cho, Aichi, 470-0151, Japan
| | - Yasuhiro Morita
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Togo-cho, Aichi, 470-0151, Japan
| | - Satoshi Ohkura
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Togo-cho, Aichi, 470-0151, Japan
| | - Hiroko Tsukamura
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan.
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Moore AM, Novak AG, Lehman MN. KNDy Neurons of the Hypothalamus and Their Role in GnRH Pulse Generation: an Update. Endocrinology 2023; 165:bqad194. [PMID: 38170643 PMCID: PMC10768882 DOI: 10.1210/endocr/bqad194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024]
Abstract
There is considerable evidence that synchronized activity within a reciprocally connected population of cells in the arcuate nucleus (ARC) coexpressing kisspeptin, neurokinin B (NKB), and dynorphin (KNDy cells) is crucial for the generation of gonadotrophin-releasing hormone (GnRH) pulses in mammals. The initial "KNDy hypothesis" proposed that pulsatile GnRH secretion is elicited by episodic kisspeptin release from KNDy cells following synchronized activation and termination of the population by NKB and dynorphin, respectively. Since then, the role of KNDy cells as a critical component of the pulse generator has been further supported by studies at the single-cell level, demonstrating that the population is both necessary and sufficient for pulsatility. In addition, there have been considerable modifications and expansion of the original hypothesis, including work demonstrating the critical role of glutamate in synchronization of the KNDy cell network, functional interactions with other ARC subpopulations, and the existence of species differences in the role of dynorphin in pulse generation. Here we review these recent changes and discuss how the translation of these findings has led to the development of new therapies for disorders related to pulse generation. We also outline critical gaps in knowledge that are currently limiting the application of KNDy research in the clinic, particularly regarding the role of dynorphin in pulse generation in primates.
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Affiliation(s)
- Aleisha M Moore
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
| | - Alyssa G Novak
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
| | - Michael N Lehman
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
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