Immunohistochemical localization of glutamate-containing neurons in the lateral reticular nucleus projecting to the cerebellar vermis in the kitten

Abstract

The lateral reticular nucleus (LRN) and afferents to the cerebellum are known to contain glutamate-like immunoreactive (Glu-LI) neurons and axons, respectively. However, such a direct link between the Glu-LI LRN neurons and the cerebellar vermal cortex has not been identified. In this study we have combined the retrograde transport of rhodamine labeled latex microspheres and immunofluorescence histochemistry to determine the locations of Glu-LI neurons of the kitten reticulocerebellar system. Following microsphere injections into the cerebellar vermis (lobules V–VII), retrogradely labeled neurons were encountered throughout the rostrocaudal extent of the LRN. More than 60% ( n = 3 kittens) of these retrogradely labeled neurons were immunostained for Glu-like immunoreactivity. Our observations of the Glu- like immunoreactivity in a majority of the reticulocerebellar neurons suggest that Glu in these neurons may participate in LRN's control of target neuron activities in the cerebellar vermis of kittens.