Cerebellar nuclei aspartate

Fig. 112. Retrograde transport of [ HJcholine (A,B) to perikarya (arrow-heads) in medial part of nucleus interpositus (Int) or in lateral cerebellar nucleus (LatC) and of wheat germ agglutinin-coupled HRP (E,F), but absence of retrogradely labelled elements in corresponding regions after application of D-pH]aspartate to the red nucleus (C,D), Rat, bright-field (A,E) as well as dark-field (B,F) illumination. Cresyl violet counterstaining. Bars = 0.5 mm. Bernays et al. (1988).

Fig. 180. Schematic illustration of the result of D-[ H]aspartate injection into lobules IV and V of the cerebellum of the rat. In the sketches of the cerebellar sections, retrogradely labelled axons and axon collaterals are indicated by lines and dots. Filled dots in the olives indicate the location of labelled cells. Retrograde labelling in cells of the inferior olive is also illustrated in more detail in the diagrams on the right. BP = brachium pontis DAO = dorsal acessory olive DN = Deiters nucleus FN = fastigial nucleus LL = lateral lemniscus LLV = ventral nucleus of the lateral lemniscusw MAO = medial accessory olive OI = inferior olive OS = superior olive PN = pontine nuclei PO = principal olive RB = restiform body I-X lobules I-X. Wiklund et al. (1984).

The investigations of Wiklund et al. (1984), using selective retrograde transport of [ H]D-aspartate were done in rats. The injection sites in the cerebellar cortex were relatively large and defied a detailed analysis of the material in terms of zones. Their experiments clearly confirmed the presence of branching olivocerebellar fibers between the anterior lobe and lobule VIII of the caudal vermis and the paramedian lobule. Moreover, their experiments clearly showed the presence of collateral projections to the cerebellar nuclei and to Deiters nucleus (Fig. 180). 

Aspartate is closely related metabolically and chemically to glutamate. In many respects it is difficult to differentiate between aspartate and glutamate as neurotransmitter candidates (Fonnum, 1984). There are, however, some fibers and terminals in which aspartate is regarded as a stronger transmitter candidate than glutamate. These include the cerebellar climbing fibers (Wiklund et al., 1982), hippocampal commissural fibers (Nadler et al., 1978), olfactory tract (Collins and Probett, 1981), cochlear nucleus afferents (Wenthold, 1979), and spinal cord intemeurons (Davidoff et al., 1967)... 

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