In:
Frontiers in Endocrinology, Frontiers Media SA, Vol. 13 ( 2022-11-8)
Abstract:
Kisspeptin neurons are mainly located in the arcuate (Kiss1 ARC , vis-à-vis the GnRH pulse generator) and anteroventral periventricular nucleus (Kiss1 AVPV , vis-à-vis the GnRH surge generator). Kiss1 ARC send fibre projections that connect with Kiss1 AVPV somata. However, studies focused on the role of Kiss1 ARC neurons in the LH surge are limited, and the role of Kiss1 ARC projections to AVPV (Kiss1 ARC→AVPV ) in the preovulatory LH surge is still unknown. To investigate its function, this study used optogenetics to selectively stimulate Kiss1 ARC→AVPV and measured changes in circulating LH levels. Kiss1 ARC in Kiss-Cre-tdTomato mice were virally infected to express channelrhodopsin-2 proteins, and optical stimulation was applied selectively via a fibre optic cannula in the AVPV. Sustained 20 Hz optical stimulation of Kiss1 ARC→AVPV from 15:30 to 16:30 h on proestrus effectively induced an immediate increase in LH reaching peak surge-like levels of around 8 ng/ml within 10 min, followed by a gradual decline to baseline over about 40 min. Stimulation at 10 Hz resulted in a non-significant increase in LH levels and 5 Hz stimulation had no effect in proestrous animals. The 20 Hz stimulation induced significantly higher circulating LH levels on proestrus compared with diestrus or estrus, which suggested that the effect of terminal stimulation is modulated by the sex steroid milieu. Additionally, intra-AVPV infusion of glutamate antagonists, AP5+CNQX, completely blocked the increase on LH levels induced by Kiss1 ARC→AVPV terminal photostimulation in proestrous animals. These results demonstrate for the first time that optical stimulation of Kiss1 ARC→AVPV induces an LH surge-like secretion via glutamatergic mechanisms. In conclusion, Kiss1 ARC may participate in LH surge generation by glutamate release from terminal projections in the AVPV.
Type of Medium:
Online Resource
ISSN:
1664-2392
DOI:
10.3389/fendo.2022.1036235
Language:
Unknown
Publisher:
Frontiers Media SA
Publication Date:
2022
detail.hit.zdb_id:
2592084-4
