Toshiya Shiojima

Trophic effect of various neuropeptides on the cultured ventral spinal cord of rat embryo

We studied the trophic effects of various neuropeptides, including substance P (SP), thyrotropin-releasing hormone (TRH), neurotensin (NT) and bombesin (BN) on explanted cultures of ventral spinal cord from 13- to 14-day-old rat embryos. In groups, receiving one type of drug only, there was a significant neurite-promoting effect (NPE) in SP, TRH and BN-treated cultures. At a concentration of 10(-12) M the most potent effect was shown by SP. However, BN had the most potent action at concentrations greater than 10(-10) M. It also became clear that there were maximum and minimum effective concentrations for these 3 neuropeptides. NT had no NPE at any concentration. There was no additional NPE when any two or all four of these neuropeptides were given simultaneously. Our results demonstrate that BN, SP, and TRH have a trophic effect on ventral spinal cord in cultures, and may contribute to a therapeutic strategy in amyotrophic lateral sclerosis.

Neuroprotective effect of various cytokines on developing spinal motoneurons following axotomy.

Ciliary neurotrophic factor (CNTF), a multipoietic factor, on a variety of neurons, prevents axotomy-induced motoneuron loss and can improve the outcome of murine motor neuron disease (MND). We carried out a study to determine whether other cytokines rescue spinal motoneurons from axotomy-induced cell death. Unilateral sciatic nerve was transected in neonatal rats. Two doses of recombinant murine cholinergic differentiation factor/leukemia inhibitory factor (CDF/LIF), recombinant rat CNTF, recombinant human granulocyte-colony stimulating factor (G-CSF), recombinant human interleukin-6 (IL-6), recombinant human tumor necrosis factor beta (TNF beta), or vehicle were administered daily for 2 weeks by intraperitoneal injection. After treatment, the number of spinal motoneurons was determined at the level of L4-5 segments. In comparison with vehicle, the higher doses of CDF/LIF, CNTF, and IL-6, and the lower doses of CDF/LIF and IL-6 significantly retarded the loss of motoneurons. G-CSF and TNF beta failed to inhibit motoneuron death. CDF/LIF and IL-6 rescued motoneurons from the retrograde death following axotomy, in a similar manner to CNTF. These results provide evidence that several cytokines may have therapeutic potential in human axonopathy or MND.

Cognitive impairment in amyotrophic lateral sclerosis and its relation to motor disabilities

The performance of patients with amyotrophic lateral sclerosis (ALS) on selective neuropsychological tests was examined in regard to the applicability of such examinations to diagnosis. Eighteen patients with ALS, and 15 age‐and education‐matched controls were given a battery of tests designed to assess motor and intellectual functions. The ALS group displayed significantly lower scores on all tests than those in the control group. Correlation analyses on the several motor and neuropsychological results in ALS group revealed that there was a significant negative correlation between upper motor symptoms and mini‐mental state examination, as well as memory tests.

Coadministration of interleukin-6 (IL-6) and soluble IL-6 receptor delays progression of wobbler mouse motor neuron disease

Interleukin-6 (IL-6), a multipotential cytokine, initiates signal transduction pathways similar to those of ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF). These molecules share the signal transducing receptor component, gp130. IL-6 triggers homodimerization of gp130, whereas CNTF and LIF induce heterodimerization of gp130 and LIF receptor. Although CNTF or LIF treatment attenuates motor deficits in wobbler mouse motor neuron disease (MND), neuroprotective effects of IL-6 on this animal have not yet been clarified. Here we studied whether simultaneous treatment with IL-6 and soluble IL-6 receptor (sIL-6R) can ameliorate symptomatic and neuropathological changes in wobbler mouse MND. After clinical diagnosis at postnatal age 3-4 weeks, wobbler mice received subcutaneous injection with human recombinant IL-6 (1.0 mg/kg), human sIL-6R (0.5 mg/kg), IL-6 + sIL-6R or vehicle, daily for 4 weeks in a blind fashion. Compared to vehicle, coadministration with IL-6 and sIL-6R potentiated grip strength, attenuated muscle contractures in the forelimbs, reduced denervation muscle atrophy and prevented degeneration of spinal motor neurons. Single administration with IL-6 or sIL-6R did not retard the symptomatic and neuropathological progression, although IL-6-treated mice did not raise anti-IL-6 antibodies. Treatment with IL-6 + sIL-6R, but not with IL-6 or sIL-6R alone delayed progression of wobbler mouse MND. Our results indicate that the neuroprotective mechanism for IL-6/sIL-6R on wobbler mouse MND differs from that of CNTF or LIF alone. We hypothesize that IL-6/sIL-6R complex may function on motor neurons through activation and homodimerization of gp130.

S100β prevents the death of motor neurons in newborn rats after sciatic nerve section

We have examined whether S100 beta rescues axotomized spinal motor neuron death. Animals that had undergone transection of the sciatic nerve at birth were treated either with S100 beta, or the vehicle. The number of surviving motor neurons and the motor neuron diameter was assessed 14 days later. Treatment with S100 beta rescued motor neuron death and preserved the motor neuron diameter in the lesioned side. These results suggest that S100 beta is a neurotrophic factor for motor neurons in vivo and this agent may have therapeutic potential in damaged motor neuron disorder.

Increased plasma concentrations of aspartate, glutamate and glycine in Parkinson's disease

We measured fasting plasma amino acids in 20 patients with Parkinsons disease (PD) and 20 controls matched for age and sex. PD patients had significant elevations in plasma levels of aspartate, glutamate and glycine. The levels of other amino acids were not significantly different from those found in controls. No correlation was noted between PD severity and the degree of abnormality of plasma amino acids. We conclude that excitatory amino acids may be altered in patients with PD, and raise the possibility that neuroexcitotoxic mechanisms may be involved in the neurodegeneration of PD.

Deprenyl enhances neurite outgrowth in cultured rat spinal ventral horn neurons

Deprenyl, a selective monoamine oxidase B inhibitor, is effective in Parkinsons disease, and can slow the cognitive deterioration in Alzheimers disease. However, it is not known whether this agent has a trophic effect on spinal motor neurons. We have studied neurotrophic effects of deprenyl on spinal motor neurons, using explanted ventral spinal cord culture from 13-day-old rat embryos. Deprenyl-treated cultures significantly enhanced neurite outgrowth with cultures of ventral spinal cord. Our data suggest that deprenyl is one of the candidate for neurotrophic factors on spinal motor neurons in vitro. A possible role for deprenyl in amyotrophic lateral sclerosis remains to be defined.

Effect of transforming growth factor β1 on spinal motor neurons after axotomy

Abstract Glial cell line-derived neurotrophic factor (GDNF), a member of the transforming growth factor β (TGF-β) family, has potent effects on developing motor neurons. TGF are pluripotent cytokines that exert biological effects on a variety of neurons. TGF β 1 , on the other hand, promotes motor neuron survival in vitro and saves motor neurons from naturally occurring cell death. Here we investigate the neurotrophic effects of TGF β 1 , for axotomized motor neuron death. The sciatic nerve was cut in newborn rats and TGF β 1 , was injected, either by intraperitoneally or by lesion site, for 14 days after transection. Two or six weeks postlesion, the number and the diameter of motor neurons was assessed. TGF β 1 , significantly attenuated axotomy induced motor neuron death by intraperitoneal administration or by lesion site administration at 2 weeks after neonatal axotomy in a similar way. However, no effect was observed at 6 weeks after nerve lesion, despite continuous application of TGF β 1 , daily for 14 days. These results indicate that TGF β 1 , can prevent the death of motor neurons in vivo, but it cannot permanently rescue lesioned motor neurons.

CNQX prevents spinal motor neuron death following sciatic nerve transection in newborn rats.

A rapid and reproducible spinal motor neuron death occurs after sciatic nerve transection in neonatal rats. This neuronal death could be due to lack of retrogradely transported target derived neurotrophic factors, such as ciliary neurotrophic factor, brain-derived neurotrophic factor, leukemia inhibitory factor and glial cell line-derived neurotrophic factor. Another hypothesis suggests that glutamate and its receptors has been implicated as possible mechanism for motor neuron death. In order to investigate the effect of N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists on axotomy-induced cell death in the spinal motor neurons of neonatal rats, we have studied neuroprotective effects of these receptor antagonists. Newborn rats were anesthetized with hypothermia. Sciatic nerve was transected near the obturator tendon in the left thigh. Animals were then treated daily with MK-801, APV, and CNQX for 14 days with intraperitoneal injections. Control animals received PBS in the same fashion. After the treatment, the number of spinal motor neurons in the L4-6 was counted. MK-801 and APV did not show any significant neuroprotective effect. By contrast, the number of surviving motor neurons was greater in animals that were treated with 1.0, 2.0 and 4.0 mg/kg of CNQX. This neuroprotective effect was not dose-related. We demonstrate that neuroprotective effect of CNQX on axotomized motor neurons, raises a possibility that such a agent may have therapeutic potential in motor neuronopathy and amyotrophic lateral sclerosis.

Trophic effect of angiotensin II, vasopressin and other peptides on the cultured ventral spinal cord of rat embryo*

We studied trophic effects of angiotensin II, vasopressin, cholecystokinin, and oxytocin on explanted ventral spinal cord cultures from 13- and 14-day-old rat embryos. There was a significant neurite promoting effect of the spinal cord cultures by using angiotensin II, vasopressin, and cholecystokinin. Cholecystokinin had the most potent effect at any concentrations. The minimum effective concentration was 10(-8) M in angiotensin II and vasopressin and 10(-12) M in cholecystokinin, respectively. The effect of angiotensin II and vasopressin was dependent on concentrations. However, the rate and grade of neurite appearance did not correlate with the concentrations of cholecystokinin. Oxytocin had no neurotrophic effect at any concentrations. Our results demonstrated that angiotensin II, vasopressin and cholecystokinin have neurotrophic effects on the ventral spinal cord in cultures, and may be candidates for therapeutic trials of amyotrophic lateral sclerosis.