[Study of vestibular efferent neurons of the guinea pig by the technic of retrograde axonal transport of horseradish peroxidase and with fluorochromes].

Vestibular efferent neurons were identified in different structures of guinea pig medulla using retrograde labelling by horseradish peroxidase and transport-specific fluorochromes. Two groups of vestibular efferent neurons with bilateral projections were found. These groups were situated dorsally and ventrally to the facial nerve fibre pathway. Dorsal group of vestibular efferent neurons consisted of small cells located in close proximity to the genu and the root of facial nerve and in subependymal granular layer of the 4th ventricle. Ventral group comprised middle-size cells usually with weak tracer accumulation; these cells were scattered in vast area of lateral tegmental field within nucleus reticularis lateralis parvocellularis. According to the cell location, morphology and pattern of tracer accumulation a possibility of presence of true vestibular efferents and satellite cells in studied groups is discussed.