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Chromaffin cells exposed to basic fibroblast growth factor (bFGF) in vitro express characteristics of sympathetic neurons, extend neurites, and become dependent on nerve growth factor (NGF) for survival. We explored whether the growth factor responsiveness of chromaffin cells could be exploited to enhance the transdifferentiation, neurite outgrowth and functional efficacy of chromaffin cells implanted into rats with unilateral 6-hydroxydopamine lesions. Cografts of neonatal chromaffin cells and fibroblasts genetically modified to produce bFGF were placed into the dopamine-depleted striatum of adult rats. Either control-transfected or NGF-producing fibroblasts were then transplanted 1 mm distal to the cograft. Chromaffin cells transdifferentiated under the influence of bFGF, as indicated by the growth of neurites and the expression of neuron-specific proteins. Distal grafts of NGF-producing fibroblasts successfully induced chromaffin neurites to traverse through the host parenchyma to the NGF source. In the absence of NGF fibroblast grafts, neither neurite extension nor good, long-term survival of the chromaffin-derived neurons was observed. Assessments of apomorphine-induced rotational behavior 2- and 4-weeks postgrafting revealed no behavioral improvements in any of the groups. These results indicate that localized sources of growth factors are effective in inducing the transdifferentiation of grafted chromaffin cells as well as the extension of chromaffin-derived neurites into the host parenchyma. Such chromaffin cell-derived neurons are, however, functionally ineffective in this rat model of Parkinson's disease. Whether the lack of behavioral improvement reflected the tropic growth of neurites to an inappropriate striatal region or the noradrenergic nature of the chromaffin cell-derived neurons remains to be clarified. Nonetheless, these results caution that promoting transdifferentiation and neurite extension from engrafted chromaffin cells may not be sufficient to achieve desired functional effects of such grafts.

We have found that interleukin 3 (IL-3), a growth factor for hematopoietic cells, is a novel trophic factor for mouse and rat central cholinergic neurons. It enhanced neurite outgrowth and elevated choline acetyltransferase activity. The effect seems to be specific for cholinergic neurons, since somatostatin release and glutamic acid decarboxylase and 2′,3′-cyclic nucleotide 3′-phosphodiesterase activities were not significantly influenced by IL-3. In vivo, IL-3 was infused into the lateral ventricles of rats after unilateral axotomy of the septohippocampal pathways. Two weeks later, the IL-3-treated animals showed significant numbers of acetylcholinesterase-positive neurons remaining in the septa[ region.

Muscle mitochondrial DNA (mtDNA) from a patient with mitochondrial myopathy was examined by Southern blotting. Her family history suggests autosomal dominant inheritance of this disorder. In contrast to other cases of this myopathy that are associated with a compensatory increase of mitochondria, in this patient, the content of mtDNA was markedly decreased (15% of controls), whereas protein of the ATP synthase beta-subunit was not decreased appreciably as judged by Western blotting. In addition, the mitochondrial DNA had multiple deletions, which were located between the replication origins of the heavy strand and light strand.

We studied a large Japanese family with autosomal dominant pure hereditary spastic paraplegia (ADPHSP) clinically and genetically. To date, seven loci causing ADPHSP have been mapped to chromosomes 14q, 2p, 15q, 8q, 12q, 2q, and 19q. Among these loci, the SPG4 locus on chromosome 2p21–p22 has been shown to account for approximately 40% of all autosomal dominant hereditary spastic paraplegia (ADHSP) families. Very recently, Hazan et al. identified the SPG4 gene encoding a new member of the AAA (ATPases associated with diverse cellular activities) protein family, named spastin. We found a novel insertion mutation (nt1272–1273insA) in exon 8 of the SPG4 gene in the present family. Our study is the first to confirm the causative mutation of the SPG4 gene in Japanese. Clinically, it is noteworthy that the disease progression in the patients of this family was slow in spite of the late onset, and more than half of the patients showed severe constipation in addition to pure spastic paraplegia.

Although adrenal medullary chromaffin cells have been used extensively for intracerebral grafting, their survival has generally been poor. Improved survival of the implanted cells has been achieved by exposing the chromaffin cells to NGF in vivo. Culture studies have shown, however, that chromaffin cells are converted into sympathetic neurons when NGF is included in the medium. The degree to which such a transdifferentiation may occur in vivo has not been determined. We assessed the effects of cografting chromaffin cells with primary fibroblasts genetically engineered to express NGF. Chromaffin cells from 10 d old rats were implanted with NGF-producing or beta- galactosidase-producing primary fibroblasts (control fibroblasts) into the striatum of 6-hydroxydopamine treated adult rats of the same strain. Eight weeks postgrafting, chromaffin cells cografted with NGF- producing fibroblasts displayed many of the features of mature sympathetic neurons such as large somata, long processes, transmitter vesicles similar to those found in neurons, and positive immunolabeling for the neuronal markers neurofilament, MAP2 and SCG10. Chromaffin- derived neuron number was also significantly enhanced in the presence of NGF-producing fibroblasts. While control fibroblasts were also found to increase chromaffin cell number above that of chromaffin cells grafted alone, the control fibroblasts did not induce neuronal transdifferentiation. These results demonstrate that chromaffin cells cografted with NGF-producing fibroblasts undergo transdifferentiation in vivo and express many characteristics of mature sympathetic neurons. The consequences of this transdifferentiation on the long term survival and function of the transplanted cells in vivo remain to be clarified.

In order to reveal a functional difference between the two distinctly separate nuclei of the striatum, i.e. the caudate nucleus (Cd) and the putamen (Put), we studied the effects of local bicuculline (BIC) and picrotoxin (PTX) injection into these nuclei on the motor behavior in the cat. The extent of diffusion of the injected BIC could be approximated by determining the extent of spreading of the dye fast green FCF (FCF) mixed with BIC solution since the extent of diffusion of radioactive [3H]BIC mixed with BIC and FCF solution was almost the same as that of FCF.BIC and PTX are GABA antagonists and are assumed to activate efferent neurons of the Cd and Put by removing the action of GABA-ergic inhibitory synapses on them. A total of 28 BIC and 22 PTX injections was made in 20 adult cats, 22 aimed at the Cd and 28 at the Put. Injection of BIC or PTX to either the head or body of the Cd unilaterally induced locomotor hyperactivity without any postural asymmetry or circling tendency. When BIC or PTX was injected into the Put, dystonic movements (dystonia) towards the contralateral side appeared frequently in the neck and trunk. Even though the injected BIC or PTX often spread to the external segment of the globus pallidus, claustrum, or anterior sylvian gyrus, none of these areas was consistently associated with dystonia. These results demonstrate that the Cd and Put are differentially associated with locomotor and postural functions.

A soluble fraction was extracted from a chemically deafferentiated striatum of adult Wistar rats after unilateral lesioning of the nigrostriatal pathway by 6-hydroxydopamine (6-OHDA) injection. The soluble extract from the lesioned side enhanced the survival of cultured mesencephalic dopamine (DA) neurons of 14-day-old rat embryos as evidenced by quantitative counting of tyrosine hydroxylase-like immunoreactive cells. The neurotrophic activity of this striatal extract for DA neurons was highest 14 days after 6-OHDA injection and became negligible in 28 days. The extract showed no promoting effects on cultured γ-aminobutyric acid (GABA)-containing mesencephalic neurons. These observations indicate that the striatum of adult rats may initiate de novo synthesis of trophic substance(s) for DA neurons but not for GABA neurons when subjected to nigral dopaminergic deafferentiation.

Pedunculopontine nucleus areas were lesioned bilaterally in the rat by local injection of kainic acid. When rats so treated were tested for active avoidance behavior in shuttle boxes we found that their avoidance acquisition was completely abolished, whereas their intertrial locomotor activity and escape behavior were not affected. In the lesioned rats, choline acetyltransferase activity in the medial thalamus and substantia nigra decreased, but not in the lateral thalamus, hippocampus, or cerebral cortex. These findings suggest that the cholinergic pedunculopontine-medial thalamus projection plays an important role in memory acquisition in the rat.

Long-term effects of MPTP on striatal dopamine (DA) content and the influence of aging on the recovery were investigated in mice. Male C 57 BL 6 J mice, young (2-month-old) and mature (10-month-old), were used. Two different dosage schedules of MPTP, i.e., 4 doses subcutaneous injections of 20 mg/kg each, and 4 doses subcutaneous injections of 40 mg/kg each, were given to both young and mature mice at 12-h intervals. Assays of striatal DA and 3,4-dihydroxyphenylacetic acid (DOPAC) content were performed 1 week, 1 month, 2 months, and 3 months after the last injection of MPTP. MPTP produced a marked reduction (−75% to −80%) of striatal DA content in both young and mature mice 1 week after the last injection of MPTP. In young mice, the striatal DA content showed a partial recovery in the subsequent stages studied. In contrast, no apparent recovery occurred in mature mice until as long as 3 months after the last injection. The results suggest that mice have a capacity for partial recovery of the striatal DA contents which was depleted by MPTP, and this capacity for recovery appears to be impaired in mature mice.

A quantitative analysis of ataxia and the readiness potential were studied in four cases of ataxic hemiparesis resulting from a small infarct in the posterior limb of the internal capsule. The ataxia appeared to be the result of involvement of the corticopontine tract originating from the precentral region (areas 4 and 6) at this level. The voluntary movements of the affected limbs were characterized by slowness and irregularity similar to those seen in cerebellar ataxia. The weakness per se was not such that it could account for the ataxia. The dentato-rubro-thalamo-cortical system did not appear to be significantly involved on the basis of normal readiness potentials.

Unilateral stereotaxic microinjection of a small amount of kainic acid (KA) into the nucleus tegmenti pedunculopontinus pars compacta (TPC) of male Wistar rats produced constant ipsiversive circling behavior. The rate of the TPC-derived circling was significantly attenuated by blocking agents of dopamine systems, including haloperidol and alpha-methyl-tyrosine (both injected intraperitoneally) and also 6-hydroxydopamine (injected into the bilateral medial forebrain bundles). Administration of norepinephrine antagonists (phenoxybenzamine hydrochloride and DL-propranolol) had no effect on the rate of the TPC-derived circling. Bilateral preinjections of atropine sulfate into the ventral midbrain tegmentum, including the ventral tegmental area and the pars compacta of the substantia nigra, significantly attenuated the rate of the circling. The unilateral KA injection into the TPC dramatically increased the ratio of HVA + DOPAC/dopamine, an indicator of dopamine turnover, in the nucleus accumbens as well as in the striatum bilaterally. The increase of the ratio in the nucleus accumbens was selectively suppressed by pretreatment with atropine sulfate administered into the bilateral ventral midbrain tegmentum. These facts indicate: (1) the TPC-derived circling behavior is mediated by the dopamine system, (2) the chemical stimulation of TPC by KA might produce an activation of midbrain dopamine neurons by excitatory TPC efferents to the dopamine neurons and enhance the dopamine turnover in the nucleus accumbens as well as in the striatum, (3) the excitatory TPC efferents may be muscarinic cholinergic in accordance with previous reports.