Increase of a nerve growth factor-like protein in the cerebellum of PCD mutant mice

Similarities in the ultrastructural distribution of nerve growth factor receptor-like immunoreactivity in cerebellar Purkinje cells of the neonatal and colchicine-treated adult rat

The intracellular distribution of nerve growth factor receptor immunoreactivity was examined by electron microscopy in the cerebellum of adult and postnatal day 12 rats. The very faint immunostaining in Purkinje cells of naive adult animals was greatly amplified after colchicine treatment. Neonatal cerebellum, in contrast, contained prominent immunoreactivity in both Purkinje cells and germinal cells of the external granular layer. Intracellular distribution of the nerve growth factor receptor reaction product was very similar in Purkinje cells of both neonatal and colchicine-treated adult animals. It was consistently present along the perikaryal cell membrane, in segments of the rough endoplasmic reticulum and Golgi complex. Numerous membrane-bound aggregates of immunoreactive vesicles resembling multivesicular bodies (secondary lysosomes) were scattered throughout the cell soma, although less frequently in neonatal rats. Bulbous expansions along the proximal axons of colchicine-treated Purkinje cells were filled with such immunoreactive multivesicular bodies. These cells also displayed evidence of nerve growth factor receptor internalization in the form of immunoreactive coated vesicles situated near the cell membrane. In addition to the staining in Purkinje cells, neonatal cerebellum contained high amounts of nerve growth factor receptor reaction product along the cell membrane of germinal cells in the external granular layer. Although Purkinje cells of naive adult animals possessed little or no cell membrane-related nerve growth factor receptor immunoreactivity, reaction product was sometimes seen in cisternae of the rough endoplasmic reticulum and Golgi apparatus. These findings provide electron microscopic immunocytochemical evidence of nerve growth factor receptor synthesis, internalization, and catabolism in noncholinergic neurons of the central nervous system.

Transplantation of cerebellar anlagen to hosts with genetic cerebellocortical atrophy

Embryonic cerebellar grafts from genetically normal donors were implanted into the cerebellomedullary cistern of adult 'Purkinje cell degeneration' (pcd) and weaver mutant mice, which are respectively characterized by the selective loss of Purkinje and granule cells. Grafts placed into both mutant recipients exhibited a layered cellular organization reminiscent of the normal cerebellar cortex. Molecular, Purkinje, and granule cell layers were identifiable. Grafted Purkinje cells displayed characteristic cytological features, such as hypolemmal cisterns in association with mitochondria in the perikaryon, and lamellar structures in their axons. The cytological features of granule cell somata in the grafts appeared similar to those of mature granule cells. Electron microscopic examination of the molecular layer of the grafts revealed the presence of parallel fibers, which were not oriented in a parallel fashion; axon terminals of such fibers were often presynaptic to dendritic spines. The number of parallel fibers was markedly reduced in grafts implanted into both mutants compared to the normal cerebellar cortex; however, this phenomenon is commonly seen in cerebellum in tissue culture and in cerebellar transplants into normal hosts. It is concluded, therefore, that the environment of the mutant hosts does not affect the survival of Purkinje or granule cells and that transplantation of solid cerebellar grafts in the neurological mutants studied does not seem to pose any apparent limitations beyond those inherent to the process of cerebellar growth and differentiation outside its normal environment.

Effect of Purkinje cell loss on cerebellar gangliosides in nervous mutant mice

The distribution of cerebellar gangliosides was studied in adult (73 +/- 2 days) nervous (nr/nr) mutant mice which lose 50-90% of their Purkinje cells. This neuronal loss is associated with significant reductions in cerebellar weight and ganglioside concentration. The cerebellar dry weights (mg) and the ganglioside concentrations (microgram N-acetylneuraminic acid per 100 mg dry weight) in nr/nr mice and age-matched normal littermates (+/?) are 7.4 +/- 0.3 mg and 13.2 +/- 0.4 mg; and 411.7 +/- 4.8 micrograms and 438.5 +/- 2.1 micrograms, respectively. Abnormalities were also observed for the concentration of certain ganglioside species. Most notably, GT1a is significantly reduced by 42%, and GD3 is significantly increased by 29% in the nr/nr mice compared to the +/? mice. The nr/nr mice also express a slight but significant reduction in GT1b. No ganglioside abnormalities were observed between the nr/nr and +/? mice in cerebral cortex. We previously found reduced cerebellar GT1a content in other mutants that also lose Purkinje cells, i.e., sg/sg, pcd/pcd, and Lc/+. GT1a is not reduced, however, in wv/wv mice that lose mostly granule cells. The findings in nr/nr mice are therefore consistent with our hypothesis that GT1a is enriched in Purkinje cells. GD1a, which is enriched in mature granule cells, is not reduced in the nr/nr mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Monoaminergic nerve terminals in the cerebellar cortex of Purkinje cell degeneration mutant mice: fine structural integrity and modification of cellular environs following loss of Purkinje and granule cells

The cerebellar cortex of normal and Purkinje cell degeneration mutant mice was examined by electron microscopy after fixation with potassium permanganate for the demonstration of small granular vesicles in monoaminergic nerve terminals. In control mice, monoaminergic terminals were found mainly in apposition to Purkinje cell dendrites. After the degeneration of Purkinje cells, which constitute the major target for monoaminergic fibres in the cerebellum, monoaminergic terminals persisted in the cerebellar cortex of Purkinje cell degeneration mutant mice. They were ensheathed by astroglial processes in most of the instances. They were also apposed to boutons that contained agranular vesicles, and to stellate cells in the molecular layer. Clear synaptic specializations in the form of thickening of the synaptic membranes were not observed in either control or mutant mice. It is hypothesized that the survival of monoaminergic axons following loss of their target cells may be attributed to the lack of intimate adhesion to their target elements, to a possible functional interaction with the glia, or to the integrity of the extracerebellar terminal fields of the monoamine axon collaterals.

Noradrenergic innervation of the cerebellar cortex in normal and in Purkinje cell degeneration mutant mice: evidence for long term survival following loss of the two major cerebellar cortical neuronal populations

Purkinje cell degeneration mutant mice were examined during the course of Purkinje cell death (26 and 35 days old) and at 3, 5, 9 and 12 months of age. Glyoxylic acid fluorescence histochemistry for catecholamines was used to investigate possible alterations or reorganization of the noradrenergic fibers from the coeruleo-cerebellar system in response to the degeneration of two major cell types in the cerebellar cortex, of which one, the Purkinje cell, is reported to be the major target neuron. In control mice, noradrenergic fibers traveled in linear and tortuous profiles through the granule cell layer, formed pericellular arrays alongside Purkinje cell somata, and branched profusely into both radially oriented and longitudinally oriented chains. The density of noradrenergic varicosities diminished in the molecular layer, there was with age. In the mutants, concomitant with the progressive shrinkage of the molecular layer, there was a progressive increase in the density of noradrenergic varicosities. This was most conspicuous at 9 and 12 months of age, at which time the molecular layer has been depleted not only of Purkinje cell dendrites, but also of parallel fibers. Noradrenergic fibers in these zones formed dense parallel bundles of varicose profiles whose density reached 621.3 +/- 122.8% (mean +/- SD, n = 4) at 9-12 months of age, compared with age-matched controls. Neurochemical measurement of norepinephrine content in whole cerebellum of the Purkinje cell degeneration mutants revealed no change compared with age-matched controls. We conclude that noradrenergic innervation persists in the cerebellar cortex despite the death of Purkinje cells and most of the granule cells. Although we found an increased density of varicosities in the molecular layer of mutant mice, progressing with age, we believe that this can be explained on the basis of the resultant geometry of the altered cerebellar cortex. It appears that the health of the environment surrounding the noradrenergic fibers in cerebellar cortex has little influence on their anatomical integrity.

Partial characterization of the neurotrophic factor for maintenance of acetylcholinesterase and butyrylcholinesterase in the preganglionically denervated superior cervical ganglion of the cat in vivo

In continuation of previous reports, it was found that the neurotrophic factor (NF) of the central nervous system of the cat for the maintenance of acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7; AcChoEase) in the denervated cat superior cervical ganglion is a heat-stable compound of low molecular weight (less than 1,000) and that it is probably a peptide. Acetylcholine and nerve growth factor were eliminated as the NF; cyclic AMP produced an effect similar to that of the NF. The NF is probably not present in significant amounts in liver or skeletal muscle; it appears to be present in small intestine. It does not modify the AcChoEase content of the nondenervated cat superior cervical ganglion. Possible mechanisms of action of the NF are discussed.

Cellular distribution of gangliosides in the developing mouse cerebellum: analysis using the staggerer mutant

The distribution of cerebellar gangliosides was studied in staggerer (sg/sg) mutant mice, where the majority of granule cells die after completing their migration across the molecular layer. In addition, the external granule cell layer in sg/sg mice persists longer than in normal mice. Moreover, in the sg/sg cerebellum, Purkinje cells are significantly reduced in number, and almost none have tertiary branchlet spines. The loss of Purkinje cells and granule cells in sg/sg mice is accompanied by an early-onset reactive gliosis that continues through adulthood. By correlating changes in ganglioside composition with the well-documented histological events of cerebellar development in normal and sg/sg mice, we obtained strong evidence for a nonrandom cellular distribution of gangliosides. The sharpest reduction in the GD1a content of sg/sg cerebellum occurred after 15 days of age, coincident with granule cell loss. GT1a, on the other hand, was significantly reduced from 15 through 150 days in the sg/sg mice. GD3 is a major ganglioside of the undifferentiated granule cell, but it becomes rapidly displaced by the more complex gangliosides with the onset of granule cell maturation. In the sg/sg mice, GD3 persisted at abnormally high levels from 15 to 28 days and then accumulated through adulthood. These findings, and those from other cerebellar mouse mutants, suggest that GD1a is enriched in granule cells and that GT1a is enriched in Purkinje cells. Our findings also suggest that GT1a is more concentrated in branchlet spines than in other regions of the Purkinje cell membrane. GT1b appears to be enriched in both granule cells and Purkinje cells, whereas GM1 appears to be enriched in myelin. Furthermore, the apparent persistence of the embryonic ganglioside GD3 in sg/sg mice results from an early-onset reactive gliosis, together with a partial retardation in granule cell maturation. The accumulation of GD3 beyond 28 days reflects the continued accretion of GD3 in reactive glia.

Adrenal medulla grafts survive and exhibit catecholamine-specific fluorescence in the primate brain

Parkinson's disease most consistently involves pathologic changes in the substantia nigra, which is the major source of dopamine to the striatum. It has been shown that either fetal substantia nigra or adrenal medulla tissue implanted into the rat brain survives, produces dopamine, and improves behavioral abnormalities induced by deprivation of the caudate nucleus of its dopaminergic innervation. Thus, catecholamine-containing grafts could be potential replacements for destroyed or damaged dopaminergic neurons in patients with Parkinson's disease. To explore the potential of this therapeutic approach, fetal substantia nigra or host adrenal medulla were grafted to the denervated caudate nucleus of the rhesus monkey. Under the specific conditions of our experiment, fetal substantia nigra did not survive in either of two animals tested. On the other hand, some tissue from adrenal medulla grafts survived in all four animals tested. These grafted cells contained catecholamines, as indicated by the presence of specific glyoxylic acid-induced catecholamine fluorescence. In two of the four animals, however, the grafts contained fewer than 10 surviving cells, and in the other two animals, about 190 and 300 cells were found, respectively. Despite the small numbers of cells, this is the first demonstration that peripheral tissue autografts can survive implantation into the nonhuman primate central nervous system.