Unipolar Brush Cells

Abstract

Muñoz (1990) described monodendritic neurons in the human cerebellar cortex using chromogranin A-like immunoreactivity. Mugnaini and Floris (1994), Mugnaini, Floris, and Wright-Gross (1994), Mugnaini, Diño, and Jaarsma (1997) with antibodies to calretinin and neurofilament proteins characterized similar cells which they termed unipolar brush cells (UBC) in the granular layer of mammalian cerebellar cortex. These cells form conspicuous and elaborated asymmetric synapses with one or two mossy fiber rosettes. The cell body displays a deeply indented nucleus, large Golgi apparatus, numerous filam ents, microtubules, mitochondria and large, dense core vesicles. The cell body gives rise to a thin axon and a single large dendritic trunk, the tip of which forms a tightly packed group of branches that resemble a paintbrush as they contact the mossy rosettes. They also form symmetric and asymmetric synaptic junctions with presumed Golgi cell boutons. Acetylcholine and glutamate are apparently co-released at these synapses. At the mossy glomerulus, the UBC dendrites are intermingled with the granule cell dendrites. Their dendrioles form dendro-dendritic contacts with granule cell dendrites (Mugnaini et al., 1997).