Importance of neuroanatomical data from domestic animals to the development and testing of the KNDy hypothesis for GnRH pulse generation.
Domest Anim Endocrinol
; 73: 106441, 2020 10.
Article
em En
| MEDLINE
| ID: mdl-32113801
ABSTRACT
Work during the last decade has led to a novel hypothesis for a question that is half a century old how is the secretory activity of GnRH neurons synchronized to produce episodic GnRH secretion. This hypothesis posits that a group of neurons in the arcuate nucleus (ARC) that contain kisspeptin, neurokinin B (NKB), and dynorphin (known as KNDy neurons) fire simultaneously to drive each GnRH pulse. Kisspeptin is proposed to be the output signal to GnRH neurons with NKB and dynorphin acting within the KNDy network to initiate and terminate each pulse, respectively. This review will focus on the importance of neuroanatomical studies in general and, more specifically, on the work of Dr Marcel Amstalden during his postdoctoral fellowship with the authors, to the development and testing of this hypothesis. Critical studies in sheep that laid the foundation for much of the KNDy hypothesis included the report that a group of neurons in the ARC contain both NKB and dynorphin and appear to form an interconnected network capable of firing synchronously, and Marcel's observations that the NKB receptor is found in most KNDy neurons, but not in any GnRH neurons. Moreover, reports that almost all dynorphin-NKB neurons and kisspeptin neurons in the ARC contained steroid receptors led directly to their common identification as "KNDy" neurons. Subsequent anatomical work demonstrating that KNDy neurons project to GnRH somas and terminals, and that kisspeptin receptors are found in GnRH, but not KNDy neurons, provided important tests of this hypothesis. Recent work has explored the time course of dynorphin release onto KNDy neurons and has begun to apply new approaches to the issue, such as RNAscope in situ hybridization and the use of whole tissue optical clearing with light-sheet microscopy. Together with other approaches, these anatomical techniques will allow continued exploration of the functions of the KNDy population and the possible role of other ARC neurons in generation of GnRH pulses.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Núcleo Arqueado do Hipotálamo
/
Hormônio Liberador de Gonadotropina
/
Neurônios
Limite:
Animals
Idioma:
En
Revista:
Domest Anim Endocrinol
Assunto da revista:
ENDOCRINOLOGIA
/
MEDICINA VETERINARIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos