Premium
Kisspeptin Neurones do not Directly Signal to RFRP ‐3 Neurones but RFRP ‐3 may Directly Modulate a Subset of Hypothalamic Kisspeptin Cells in Mice
Author(s) -
Poling M. C.,
Quennell J. H.,
Anderson G. M.,
Kauffman A. S.
Publication year - 2013
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/jne.12084
Subject(s) - kisspeptin , neurokinin b , arcuate nucleus , neuropeptide , medicine , receptor , endocrinology , biology , hypothalamus , chemistry , neuroscience , substance p
The neuropeptides kisspeptin (encoded by Kiss1 ) and RF amide‐related peptide‐3 (also known as Gn IH ; encoded by Rfrp ) are potent stimulators and inhibitors, respectively, of reproduction. Whether kisspeptin or RFRP ‐3 might act directly on each other's neuronal populations to indirectly modulate reproductive status is unknown. To examine possible interconnectivity of the kisspeptin and RFRP ‐3 systems, we performed double‐label in situ hybridisation ( ISH ) for the RFRP ‐3 receptors, Gpr147 and Gpr74 , in hypothalamic Kiss1 neurones of adult male and female mice, as well as double‐label ISH for the kisspeptin receptor, Kiss1r , in Rfrp ‐expressing neurones of the hypothalamic dorsal‐medial nucleus ( DMN ). Only a very small proportion (5‐10%) of Kiss1 neurones of the anteroventral periventricular region expressed Gpr147 or Gpr74 in either sex, whereas higher co‐expression (approximately 25%) existed in Kiss1 neurones in the arcuate nucleus. Thus, RFRP ‐3 could signal to a small, primarily arcuate, subset of Kiss1 neurones, a conclusion supported by the finding of approximately 35% of arcuate kisspeptin cells receiving RFRP ‐3‐immunoreactive fibre contacts. By contrast to the former situation, no Rfrp neurones co‐expressed Kiss1r in either sex, and Tacr3 , the receptor for neurokinin B ( NKB ; a neuropeptide co‐expressed with arcuate kisspeptin neurones) was found in <10% of Rfrp neurones. Moreover, kisspeptin‐immunoreactive fibres did not readily appose RFRP ‐3 cells in either sex, further excluding the likelihood that kisspeptin neurones directly communicate to RFRP ‐3 neurones. Lastly, despite abundant NKB in the DMN region where RFRP ‐3 soma reside, NKB was not co‐expressed in the majority of Rfrp neurones. Our results suggest that RFRP ‐3 may modulate a small proportion of kisspeptin‐producing neurones in mice, particularly in the arcuate nucleus, whereas kisspeptin neurones are unlikely to have any direct reciprocal actions on RFRP ‐3 neurones.