An Immunohistochemical Study on the Expressional Dynamics of Kisspeptin Neurons Relevant to GnRH Neurons Using a Newly Developed Anti-kisspeptin Antibody

Norio Iijima
Ken Takumi
Nobuhiko Sawai
Hitoshi Ozawa

To investigate the reported discrepancy regarding the immunohistochemical expression of kisspeptin neurons
 we produced a new antibody against synthetic peptide containing the same amino acid residual sequence as rat kisspeptin10. Although the antibody showed cross-reactivities against neurons other than kisspeptin neurons
 these cross-reactivities were excluded by preabsorption with neuropeptide FF (NPFF). Immunohistochemistry using the antibody preabsorbed with NPFF showed specific kisspeptin immunoreactivities (IRs) in the arcuate nucleus (Arc)
 the inner layer of the median eminence
 and the infundibulum in the rat hypothalamus. IRs were more intense in the adult female rats than in the males. This sexual dimorphism became observable at the 7th day after birth. These IRs intensified with age. Ovariectomy enhanced the IRs in the Arc in the female rats. In contrast
 regarding IRs in the anteroventral periventricular nucleus (AVPV)
 only a few immunoreactive fibers were detected in the adult rats. We applied this antibody for the investigation of the interaction between kisspeptin fibers and gonadotropin-releasing hormone (GnRH) neurons. No direct morphological interaction between the cell bodies of GnRH neurons and kisspeptin fibers was observed in the medial preoptic area. Many projections of kisspeptin fibers were found close to the GnRH fibers in the lateral part of the median eminence. However
 we did not observe any direct contact between kisspeptin fibers and the GnRH fibers. These results suggest that kisspeptin neurons regulate GnRH neurons not via the synaptic contact but via another information transmission process that is not synapse-dependent
 such as volume transmission.

JOURNAL OF MOLECULAR NEUROSCIENCE

HUMANA PRESS INC

43

2

10.1007/s12031-010-9433-y

https://doi.org/10.1007/s12031-010-9433-y
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