The increase in the number of spines on the gonadotropin-releasing hormone neuron across pubertal development in rats

Songzi Li
Ken Takumi
Norio Iijima
Hitoshi Ozawa

The onset of puberty is initiated by an increase in the release of the gonadotropin-releasing hormone (GnRH) from GnRH neurons in the hypothalamus. However
 the precise mechanism that leads to the activation of GnRH neurons at puberty remains controversial. Spines are small protrusions on the surface of dendrites that normally receive excitatory inputs. In this study
 we analyzed the number and morphology of spines on GnRH neurons to investigate changes in synaptic inputs across puberty in rats. For morphological estimation
 we measured the diameter of the head (DH) of each spine and classified them into small-type (DH < 0.65 mu m)
 large-type (DH > 0.65 mu m) and giant-type (DH > 0.9 mu m). The greatest number of spines was observed at the proximal dendrite within 50 mu m of the soma. At the soma and proximal dendrite
 the number of spines was greater in adults than in juveniles in both male and female individuals. Classification of spines revealed that the increase in spine number was due to increases in large- and giant-type spines. To further explore the relationship between spines on GnRH neurons and pubertal development
 we next analyzed adult rats neonatally exposed to estradiol benzoate
 in which puberty onset and reproductive functions are disrupted. We found a decrease in the number of all types of spines. These results suggest that GnRH neurons become to receive more and greater excitatory inputs on the soma and proximal dendrites as a result of the changes that occur at puberty and that alteration to spines plays a pivotal role in normal pubertal development.

CELL AND TISSUE RESEARCH

SPRINGER

364

2

10.1007/s00441-015-2335-0

https://doi.org/10.1007/s00441-015-2335-0
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000374973300016&DestApp=WOS_CPL