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Chemical information captured through the vomeronasal sensory neurons is transmitted to mitral cells in the accessory olfactory bulb (AOB). Morphological characterization of AOB mitral cells is crucial to reveal the mechanisms underlying pheromone and other chemical information processing. Here, we developed a conditional genetic approach to visualize single AOB mitral cells in mice and analyzed the distribution of their apical dendritic tufts and cell bodies. We found that there is a subpopulation of superficial AOB mitral cells with small cell bodies and simple dendritic arborization. We also showed that segregation of the anterior and posterior AOB appears incomplete at the level of the mitral cell positions. Furthermore, we demonstrated that significant population of the anterior AOB mitral cells has multiple apical dendritic tufts organized in a quite small range along the dorsal-ventral axis. These findings have important implications in how various chemical signals may be processed in the AOB.

The role of inhibitory Golgi cells in cerebellar function was investigated by selectively ablating Golgi cells expressing human interleukin-2 receptor α subunit in transgenic mice, using the immunotoxin-mediated cell targeting technique. Golgi cell disruption caused severe acute motor disorders. These mice showed gradual recovery but retained a continuing inability to perform compound movements. Optical and electrical recordings combined with immunocytological analysis indicated that elimination of Golgi cells not only reduces GABA-mediated inhibition but also attenuates functional NMDA receptors in granule cells. These results demonstrate that synaptic integration involving both GABA inhibition and NMDA receptor activation is essential for compound motor coordination. Furthermore, this integration can adapt after Golgi cell elimination so as not to evoke overexcitation by the reduction of NMDA receptors.