Brain catecholamine alterations and pathological features with aging in Parkinson disease model rat induced by Japanese encephalitis virus.

We analyzed two disease model groups with rats infected by Japanese encephalitis virus (JEV), a 90-day group and a 180-day group after JEV infection. The time measured by the modified pole test showed that motor activities in these two groups were slower than those of age-matched control groups. Striatal dopamine (DA) levels were significantly decreased in all JEV-infected rats. Norepinephrine concentration in brain regions in the 180-day group was significantly decreased in the medulla oblongata and hypothalamus as compared with the control and 90-day group. Tyrosine hydroxylase-positive neurons were significantly decreased in both JEV-infected rat groups. These results suggest that DA decrease and pathological changes in JEV-infected model rats persist for a long time, at least up to 180 days, and this model will be useful for the evaluation of new anti-parkinsonian agents.

Expression of Neuropeptide Y gene in mouse testes during testicular development.

AIM: To elucidate the distribution and regulation of Neuropeptide Y (NPY) gene expression in testes under physiological and pathophysiological conditions, such as testicular development, fasting and experimental cryptorchidism. METHODS: In the first experiment, C57BL/6J male mice at the ages of 3 days as well as 2, 3, 5 and 8 weeks were used. In the second and third experiments, adult C57BL/6J male mice were subjected to fasting for 48 h and experimental cryptorchidism for 72 h. The NPY transcripts were detected by isotopic in situ hybridization histochemistry. RESULTS: The NPY transcripts were exclusively expressed in the interstitial cells regardless of the age groups and experimental conditions. The NPY mRNA levels were found to increase significantly with age (from the neonatal to prepubertal period [P<0.01] and from the prepubetal to postpubertal period [P<0.01]). Food deprivation for 48 h resulted in a significant increase in the NPY mRNA levels in the arcuate nucleus of the hypothalamus (P<0.01), but not in the testes. Experimental cryptorchidism for 72 h failed to regulate the NPY gene expression in the testes. CONCLUSION: NPY gene expression is distributed in Leydig cells and increases in line with testicular development. The regulation of testicular NPY is different from that of hypothalamic NPY.

Comparative study of the effects of isatin, an endogenous MAO-inhibitor, and selegiline on bradykinesia and dopamine levels in a rat model of Parkinson's disease induced by the Japanese encephalitis virus.

We previously reported that exogenously administered isatin, an endogenous monoamine oxidase (MAO) inhibitor, significantly increased acetylcholine (ACh) and dopamine (DA) levels in the rat striatum. Selegiline [(-)-deprenil] was developed as a MAO-B inhibitor more than 30 years ago and widely used in the treatment of Parkinson's disease. Effects of isatin or selegiline were investigated in Japanese encephalitis virus (JEV)-induced post-encephalitic parkinsonism rats by a pole test for detecting motor activity and by the determination of biogenic amine levels. Motor activity of JEV-induced rats receiving isatin (100 mg/kg per day for 1 week, i.p.) or selegiline (0.2 mg/kg per day for 1 week, i.p.) was significantly improved compared with that of untreated JEV-infected rats. Both isatin and selegiline prevented the decrease in striatal DA levels in JEV-rats. The increased turnover of DA (DOPAC/DA) induced by JEV was significantly inhibited by isatin, but not by selegiline. These results suggested that exogenously administered isatin and selegiline can improve JEV-induced parkinsonism by increasing DA concentrations in the striatum.

Urinary isatin concentrations in patients with Parkinson's disease determined by a newly developed HPLC-UV method.

Isatin, an endogenous monoamine oxidase (MAO) inhibitor, has been found in mammalian tissues. We previously reported that exogenously administered isatin significantly increased acetylcholine (ACh) and dopamine (DA) levels in the rat striatum. In order to elucidate the relationship between isatin and Parkinson's disease, we measured urinary isatin excretions in patients with Parkinson's disease using a newly developed HPLC-UV method. The recovery of this assay was approximately 102.3% at a range from 2 to 50 nmol/ml. The Coefficient of Variance (CV) for the determination at this range was approximately 2.5% for intra-assay and 6.2% for inter-assay, respectively. There was no significant difference in urinary isatin excretion between data from men and women in healthy control. The value in young age group (19-35 years old) was not significantly different compared with that of the older age group (54-84 years old). Urinary isatin levels in patients with Parkinson's disease tended to increase in accordance to the Hoehn and Yahr criteria. This is the first study in which a significant increase in urinary isatin excretion was observed at Stage III, IV and V in patients with Parkinson's disease. Urinary isatin concentrations in drug-treated patients with Parkinson's disease (at Stage I and II) tended to decrease compared with those of patients without medication. These results demonstrated that urinary isatin excretion may serve as an endogenous diagnostic marker for the clinical severity of Parkinson's disease.

Expression of recombinant feline serum amyloid A (SAA) protein.

Feline serum amyloid A (SAA) cDNA clone was isolated from a hepatic mRNA of a mixed-breed cat. The feline SAA cDNA clone contains 333 nucleotides and deduced amino acid sequence shows 87.4%, 73.9%, and 65.8% homology with dog, human and mouse SAA respectively. Relative to the human and mouse SAA proteins, an additional peptide of eight amino acids is specified in the feline cDNA clone. Recombinant feline SAA (rfSAA) was expressed at high levels using pGEX bacterial expression system. Cleavage from the fusion moiety, and purification using glutathione-sepharose yielded pure soluble form of rfSAA. Antibodies generated against rfSAA were specific for feline SAA and showed no cross-reactivity with human SAA. Furthermore, antibodies against human SAA did not react with feline SAA. These results indicate that antigenicity of feline SAA is totally different from human SAA.

[Effects of isatin, an endogenous MAO inhibitor, on dopamine (DA) and acetylcholine (ACh) concentrations in rats].

Isatin (indole-2,3-dione), an endogenous inhibitor of monoamine oxidase (MAO), has several physiological properties for stress and anxiety. We previously identified isatin in the brain of stroke-prone spontaneously hypertensive rats (SHRSP) using gas-chromatography mass spectrometry. This study elucidated the effects of isatin on the ACh and DA levels of brain tissues in rats. Furthermore, we evaluated the effect of isatin on DA levels in a rat model of Parkinson's disease induced by Japanese encephalitis virus. Striatal ACh and DA levels significantly increased at 2 hours after isatin (50-200 mg/kg, i.p.) administration. Perfused through a microdialysis probe, isatin (10(-6)-10(-4) M) also produced a significant and concentration-dependent increase in the ACh and DA concentrations in the perfusate from the rat striatum. Furthermore, urinary isatin concentrations in patients with Parkinson's disease tend to increase according to the severity of disease. Isatin (100 mg/kg, i.p.) significantly increased striatal DA levels in a rat model of Parkinson's disease. These results suggest that urinary isatin may become a diagnostic marker for the clinical severity of Parkinson's disease and that endogenous isatin, a new biological modulator, may play a role in the regulation of the brain levels of ACh by increasing the level of DA under stress.