USE OF CALCIUM-BINDING PROTEINS TO MAP INPUTS IN VESTIBULAR NUCLEI OFTHE GERBIL

We wished to determine whether calbindin and/or calretinin are appropr iate markers for vestibular afferents, a population of neurons in the vestibular nuclear complex, or cerebellar Purkinje inputs. To accompli sh this goal, immunocytochemical staining was observed in gerbils afte r lesions of the vestibular nerve central to the ganglion, the cerebel lum, or both. Eleven to fourteen days after recovery, the brain was pr ocessed for immunocytochemical identification of calretinin and calbin din. After lesion of the vestibular nerve, no calretinin staining was seen in any of the vestibular nuclei except for a population of intrin sic neurons, which showed no obvious change in number or staining patt ern. Calbindin staining was reduced in all nuclei except the dorsal pa rt of the lateral vestibular nuclei. The density of staining of each m arker, measured in the magnocellular medial vestibular nucleus, was si gnificantly reduced. After the cerebellar lesion, no differences in ca lretinin staining were noted. However, calbindin staining was greatly reduced in all nuclei. The density of staining, measured in the caudal medial vestibular nucleus, was significantly lower. After a combined lesion of the cerebellum and vestibular nerve, the distribution and de nsity of calretinin staining resembled that after vestibular nerve sec tion alone, whereas calbindin staining was no longer seen. This study demonstrates that calretinin and calbindin are effective markers for t he identification of vestibular afferents. (C) 1997 Wiley-Liss, Inc.