抄録
In immature female mice, pheromones promote sexual maturations such the acceleration of an increase in uterine weight and the advance of the onset of first oestrus. Pheromones induce different effects on mature females such as Bruce effect and the suppression of oestrus, indicating that the role of pheromones on physical state develops with maturation. In the present study, we examined the changes in sensitivity to urinary pheromone excreted from males in female mice to explore the maturation of treatment of pheromonal information in the accessory olfactory bulb (AOB). After exposure to male urine, many Fos-immunorective (Fos-ir) cells appeared in the periglomerular cell (PGC), mitral/tufted cell and granule cell (GC) layers of the AOB of the immature female mice. The densities of Fos-ir cells in the immature female mice after exposure to male urine were higher than those in the mature females. Pheromonal information is modulated by GABAergic interneurons such as the PGC and GC. To explore the essential GABA receptors that modulate pheromonal information during maturation, we searched for GABAA receptor subtypes expressed in the mouse AOB by RT-PCR analysis. In the PGC layer, amplification of fragment for subtype 1, 2 and 3 was clearly detected in mature females but not in the immature females suggesting that development of the inhibitory system in the AOB may regulate pheromonal sensitivity in the AOB. [J Physiol Sci. 2008;58 Suppl:S166]
