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Electrophysiological and Morphological Evidence for Synchronized GnRH Pulse Generator Activity Among Kisspeptin/Neurokinin B/Dynorphin A (KNDy) Neurons in Goats
被引:0
作者:
Wakabayashi, Yoshihiro
[1
]
Yamamura, Takashi
[1
]
Sakamoto, Kohei
[1
,2
]
Mori, Yuji
[2
]
Okamura, Hiroaki
[1
]
机构:
[1] Natl Inst Agrobiol Sci, Neurobiol Lab, Ibaraki 3050862, Japan
[2] Univ Tokyo, Lab Vet Ethol, Tokyo 1138657, Japan
基金:
日本学术振兴会;
关键词:
GnRH pulse generator;
Goat;
Kisspeptin;
Neurokinin B;
MONKEY MACACA-MULATTA;
OVINE PREOPTIC AREA;
ARCUATE NUCLEUS;
NEUROKININ-B;
HORMONE NEURONS;
KISSPEPTIN NEURONS;
FEMALE RAT;
HYPOGONADOTROPIC HYPOGONADISM;
GONADOTROPIN-SECRETION;
OVARIECTOMIZED RATS;
D O I:
暂无
中图分类号:
S8 [畜牧、 动物医学、狩猎、蚕、蜂];
学科分类号:
0905 ;
摘要:
Neurons in the arcuate nucleus (ARC) that concomitantly express kisspeptin, neurokinin B (NKB) and dynorphin A are termed KNDy neurons and are likely candidates for the intrinsic gonadotropin-releasing hormone (GnRH) pulse generator. Our hypothesis is that KNDy neurons are functionally and anatomically interconnected to generate discrete neural signals that govern pulsatile GnRH secretion. Our goal was to address this hypothesis using electrophysiological and anatomical experiments in goats. Bilateral electrodes targeting KNDy neurons were implanted into ovariectomized goats, and GnRH pulse generator activity, represented by characteristic increases in multiple-unit activity (MUA volleys), was measured. Spontaneous and pheromone- or senktide (an NKB receptor agonist)-induced MUA volleys were simultaneously recorded from both sides of the ARC. An anterograde tracer, biotinylated dextran amine (BDA), was also injected unilaterally into the ARC of castrated male goats, and the distribution of fibers containing both BDA and NKB was examined using dual-labeling histochemistry. The results showed that MBA volleys, regardless of origin (spontaneous or experimentally induced), occur simultaneously between the right and left sides of the ARC. Tract tracing indicated that axons projecting from NKB neurons in the ARC were directly apposed to other NKB neuronal cells located bilaterally in the ARC. These results demonstrate that GnRH pulse generator activity occurs synchronously between both sides of the ARC in goats and that KNDy neurons are bilaterally interconnected in the ARC via NKB-containing fibers. Taken together, the results suggest that KNDy neurons form a neuronal circuit to synchronize burst activity among KNDy neurons and thereby generate discrete neural signals that govern pulsatile GnRH secretion.
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页码:40 / 48
页数:9
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