Postnatal changes in the concentration and distribution of cholinesterase in the cerebellar cortex of rats

Abstract

The changing pattern of ChE staining in the cerebellar cortex was examined in rats 0, 3, 7, 10, 15, 21, and 30 days old. For correlative purposes, Golgi-impregnated sections from rats of the same ages were also studied. The following conclusions were drawn about the mature cerebellum. (a) Most of the nerve cells of the cerebellar cortex (Purkinje, granule, basket, and stellate cells) are noncholinergic; the Golgi cells are cholinergic. (b) Of the noncholinergic neurons, the Purkinje cells are noncholinoceptive because the climbing fibers, parallel fibers, and the basket terminals are noncholinergic. (c) A large proportion of the mossy fibers that apparently originate directly or indirectly in the acousticovestibular system are cholinergic; the others are predominantly noncholinergic. (d) The granule cells are cholinoceptive. This is due to Golgi-cell terminals in the glomeruli in all lobules and to the additional cholinergic mossy fiber terminal in the lobules that receive acousticovestibular projection (nodulus, flocculus, part of uvula, tuber, folium, and lingula). (e) Available evidence in the literature about other neurochemical transmitters in the cerebellar cortex was considered. The following conclusions were drawn about the postnatal development of the “wiring pattern” of the cerebellar cortex. (a) In the newborn rat the only input to the Purkinje cell is by way of climbing fibers which contact their soma. (b) A few days after birth the cholinergic mossy fibers reach the zone of Purkinje cells. The transient ChE staining of Purkinje cells and the development of transient perisomatic processes suggest that mossy fibers may establish direct contact with the Purkinje cells during this period. (c) The cessation of Purkinje-cell staining during the second week, the descent of the precursors of granule cells from the external into the internal granular layer, and the increased staining of the glomeruli indicate that the mossy fibers establish contact with the granule cells.