Downregulation of lncRNA BACE1-AS improves dopamine-dependent oxidative stress in rats with Parkinson's disease by upregulating microRNA-34b-5p and downregulating BACE1.

Objective: Long noncoding RNAs (lncRNAs) have already been proposed to function in Parkinson's disease (PD). However, the role of lncRNA BACE1-AS in PD has never been discussed. This study aims to examine the mechanism of BACE1-AS on oxidative stress injury of dopaminergic neurons in PD rats.Methods: Rat models of PD were established through the injection of 6-hydroxydopamine. The rotation of rats was induced by intraperitoneal injection of apomorphine, and number of rotations per minute was detected. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), glutamic acid (Glu), dopamine (DA), tyrosine hydroxylase (TH), α-synuclein and inducible nitric oxide synthase (iNOS) in the substantia nigra of rats in each group were detected. Apoptosis and pathological changes in the substantia nigra were also observed. BACE1-AS, miR-34b-5p, BACE1, Bax and Bcl-2 expression in the substantia nigra were detected. The binding of BACE1-AS and miR-34b-5p and the targeting relationship of miR-34b-5p and BACE1 were further determined.Results: Downregulated BACE1-AS reduced iNOS, α-synuclein and Glu levels and elevated DA and TH levels in the substantia nigra of PD rats. Downregulated BACE1-AS repressed apoptosis and oxidative stress injury in the substantia nigra neurons of PD rats. BACE1-AS specifically bound to miR-34b-5p. BACE1 was a direct target gene of miR-34b-5p.Conclusion: Collectively, our study reveals that downregulation of lncRNA BACE1-AS inhibits iNOS activation in the substantial nigra and improve oxidative stress injury in PD rats by upregulating miR-34b-5p and downregulating BACE1.

A functionalized hydroxydopamine quinone links thiol modification to neuronal cell death.

Recent findings suggest that dopamine oxidation contributes to the development of Parkinson's disease (PD); however, the mechanistic details remain elusive. Here, we compare 6-hydroxydopamine (6-OHDA), a product of dopamine oxidation that commonly induces dopaminergic neurodegeneration in laboratory animals, with a synthetic alkyne-functionalized 6-OHDA variant. This synthetic molecule provides insights into the reactivity of quinone and neuromelanin formation. Employing Huisgen cycloaddition chemistry (or "click chemistry") and fluorescence imaging, we found that reactive 6-OHDA p-quinones cause widespread protein modification in isolated proteins, lysates and cells. We identified cysteine thiols as the target site and investigated the impact of proteome modification by quinones on cell viability. Mass spectrometry following cycloaddition chemistry produced a large number of 6-OHDA modified targets including proteins involved in redox regulation. Functional in vitro assays demonstrated that 6-OHDA inactivates protein disulfide isomerase (PDI), which is a central player in protein folding and redox homeostasis. Our study links dopamine oxidation to protein modification and protein folding in dopaminergic neurons and the PD model.

The aqueous extract of Albizia adianthifolia leaves attenuates 6-hydroxydopamine-induced anxiety, depression and oxidative stress in rat amygdala.

BACKGROUND: While the Albizia adianthifolia (Schumach.) W. Wright (Fabaceae) is a traditional herb largely used in the African traditional medicine as analgesic, purgative, antiinflammatory, antioxidant, antimicrobial, memory-enhancer, anxiolytic and antidepressant drug, there are no scientific data that clarify the anxiolytic and antidepressant-like effects in 6-hydroxydopamine (6-OHDA)-lesioned animal model of Parkinson's disease. This study was undertaken in order to identify the effects of aqueous extract of A. adianthifolia leaves on 6-hydroxydopamine-induced anxiety, depression and oxidative stress in the rat amygdala. METHODS: The effect of the aqueous extract of A. adianthifolia leaves (150 and 300 mg/kg, orally, daily, for 21 days) on anxiety and depression was assessed using elevated plus-maze and forced swimming tests, as animal models of anxiety and depression. Also, the antioxidant activity in the rat amygdala was assessed using assessed using superoxide dismutase, glutathione peroxidase and catalase specific activities, the total content of the reduced glutathione, protein carbonyl and malondialdehyde levels. Statistical analyses were performed using by one-way analysis of variance (ANOVA). Significant differences were determined by Tukey's post hoc test. F values for which p < 0.05 were regarded as statistically significant. Pearson's correlation coefficient and regression analysis were used in order to evaluate the connection between behavioral measures, the antioxidant defence and lipid peroxidation. RESULTS: 6-OHDA-lesioned rats exhibited the following: decrease of the exploratory activity, the percentage of the time spent and the number of entries in the open arm within elevated plus-maze test and decrease of swimming time and increase of immobility time within forced swimming test. Administration of the aqueous extract significantly exhibited anxiolytic- and antidepressant-like effects and also antioxidant potential in the rat amygdala. CONCLUSIONS: Our results suggest that the aqueous extract ameliorates 6-OHDA-induced anxiety and depression by attenuation of the oxidative stress in the rat amygdala. These pieces of evidence accentuate its use in traditional medicine.

[NON-RESPIRATORY FUNCTION OF THE LUNGS IN THE NIGROSTRIATAL DOPAMINERGIC SYSTEM DYSFUNCTION].

The study presents a comprehensive of the metabolism and the fractional composition of li- pids surfactant, water balance, hemostatic activity of the lungs in neyrodegeneration substantia nigra of the brain induced by stereotaxic microinjection of 6--hydroxydopamine and systemic administration of haloperidol. It is shown that a breach of dopaminergic neurotransmission leads to deterioration of surface-active properties of the alveolar lining of the complex against a decrea- se of phospholipids, cholesterol, phosphatidylcholine and lysophospholipids enhance the pulmo- nary surfactant in the activation of phospholipase hydrolysis and lipid peroxidation. Intranigral introduction neurotoxin accompanied by increased blood supply to the lungs and the blood coagu- lation potential of the pulmonary circulation, the blockade D2-receptors--hyporhydration lung tissue. The results obtained indicate the formation of dysregulation pneumopathy dysfunction nigrostriatal dopaminergic system.

Binding of [3H]mazindol to cardiac norepinephrine transporters: kinetic and equilibrium studies.

The norepinephrine transporter (NET) is the carrier that drives the neuronal norepinephrine uptake mechanism (uptake1) in mammalian hearts. The radioligand [3H]mazindol binds with high affinity to NET. In this study, the kinetics of [3H]mazindol binding to NET were measured using a rat heart membrane preparation. Results from these studies were used to set up saturation binding assays designed to measure cardiac NET densities (Bmax) and competitive inhibition assays designed to measure inhibitor binding affinities (KI) for NET. Saturation binding assays measured NET densities in rat, rabbit, and canine hearts. Assay reproducibility was assessed and the effect of NaCl concentration on [3H]mazindol binding to NET was studied using membranes from rat and canine hearts. Specificity of [3H]mazindol binding to NET was determined in experiments in which the neurotoxin 6-hydroxydopamine (6-OHDA) was used to selectively destroy cardiac sympathetic nerve terminals in rats. Competitive inhibition studies measured KI values for several NET inhibitors and substrates. In kinetic studies using rat heart membranes, [3H]mazindol exhibited a dissociation rate constant koff=0.0123+/-0.0007 min(-1) and an association rate constant kon=0.0249+/-0.0019 nM(-1)min(-1). In saturation binding assays, [3H]mazindol binding was monophasic and saturable in all cases. Increasing the concentration of NaCl in the assay buffer increased binding affinity significantly, while only modestly increasing Bmax. Injections of 6-OHDA in rats decreased measured cardiac NET Bmax values in a dose-dependent manner, verifying that [3H]mazindol binds specifically to NET from sympathetic nerve terminals. Competitive inhibition studies provided NET inhibitor and substrate KI values consistent with previously reported values. These studies demonstrate the high selectivity of [3H]mazindol binding for the norepinephrine transporter in membrane preparations from mammalian hearts.

Reactivation of HSV-1 in primates by transcorneal iontophoresis of adrenergic agents.

Transcorneal iontophoresis of adrenergic agents has been shown to reactivate latent herpes simplex virus type 1 (HSV-1) and to produce viral shedding in the tear film in rabbits and mice, but not, to date, in nonhuman primates. In this study, we demonstrated induced reactivation of latent HSV-1, viral shedding, and production of ocular lesions in nine squirrel monkeys (Saimiri sciureus) by iontophoresis of 6-hydroxydopamine (6-HD) with topical instillation of epinephrine or with iontophoresis of timolol. Monkey corneas were scarified and inoculated with McKrae strain HSV-1 on three separate occasions. All monkeys received daily intramuscular prednisolone for 39 or 46 days prior to ionotophoresis. Once latency was established, a single ionotphoresis of 6-HD was performed on both eyes in five of the monkeys, followed by 1% epinephrine given topically four times daily for 5 days. Iontophoresis of timolol was performed on both eyes in the other four monkeys once per day on 3 consecutive days. Eight of the ten eyes receiving 6-HD and epinephrine shed HSV-1; seven eyes developed deep punctate, dendritic, or geographic corneal lesions. Seven of the eight eyes receiving timolol shed HSV-1; six of the eyes developed lesions suggestive of HSV-1 specific corneal lesions. The methods used in this report were slightly different from those used to reactivate HSV-1 in rabbits, in that repeated inoculations with HSV-1 and repeated intramuscular injections with prednisolone were required; however, these results demonstrate that iontophoresis of adrenergic agents can produce shedding and recurrent epithelial lesions in the nonhuman primate.

Rotational behaviour induced by theophylline in 6-OHDA nigrostriatal denervated rats is dependent on the supersensitivity of striatal dopaminergic receptors.

We studied apomorphine- and theophylline-induced rotational behaviour in rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal pathway. It was seen that there was a direct correlation between the number of apomorphine- and theophylline-induced contralateral turns. These data suggest the existence of a relationship between theophylline-induced rotational behaviour and the degree of supersensitivity of the striatal dopaminergic receptors. Because the rotational behaviour induced by theophylline is in the same direction as dopaminergic agonists, contralateral to the nigrostriatal pathway lesion, these results suggest the possibility of a direct dopaminergic agonism of methylxanthines.

Sulfanilic acid: behavioral change related to azo food dyes in developing rats.

The effects of sulfanilic acid, a major azo food dye metabolite, were studied in normal developing rat pups and pups treated with 6-hydroxydopamine (60HDA). Chronic daily intraperitoneal injection of sulfanilic acid during the first postnatal month elicited hyperactivity and impaired shock escape performance in vehicle pups. No differences were noted in 60HDA treated rat pups receiving sulfanilic acid. These findings, which are similar to the results of our study of chronic administration of a food dye mix, suggest that sulfanilic acid may be one of the causative agents in food dye-induced behavioral changes in developing rats. While our work suggests a significant effect of azo food dyes on the developing rat central nervous system, species differences in parameters such as absorption, metabolism, and blood-brain barrier properties do not permit any extrapolation of these observations to proposed effects in children.

Ultrastructural changes in the brain of rats administered with 6-hydroxydopamine.

Adult Wistar rats were treated with 6-Hydroxydopamine (6-OHDA, 200-500 micrograms) by intraventricular injection. Two, five, seven or 14 days after the injection, the effects of 6-OHDA on rat behavior and the brain ultrastructure were observed. The increased irritability and the tendency of a decrease in self-grooming along with a reduced spontaneous movement were found in rats given 6-OHDA. The main ultrastructural alterations were observed in the nerve terminals localized in the catecholaminergic neurons, particularly the hypothalamic axon terminals. These ultrastructural changes might relate to the behavioral abnormalities in the animals.

Effect of neonatal administrations of 6-OHDA on the brain development. I. Alteration in the striatum.

Following repeated subcutaneous administrations of 6-OHDA into neonatal rats (a dose; 100 mu/g bw), the effect on the brain development was examined. The striatal dopamine fluorescence never disappeared completely even immediately after multiple administrations of 6-OHDA, however a slight reduction of the fluorescence lasted for a long time. Semithin sections stained with toluidine blue showed numerous dark necrotic neurons appearing at a 15-times higher ratio than that in controls. Such necrotic neurons always accompanied a few granular deposits around the wavy surface. In a certain area of the striatum (0.898 mm2), there were no clear changes in the cell population in neurons and glia, in the ratio of glia to neurons, and in the ratio of each cell type of glia to the total glia, but some neuronal cell loss was speculated to occur slowly. The ultrastructural alteration observed at 28, 35 and 42 postnatal days in 6-OHDA treated rats was characterized by an appearance of myelin-like membranous lamellar bodies in the boutons synapsing with neural soma. In some cases intact small synaptic vesicles were seen around the lamellar body which probably rose from cell membranes in the synaptic area. Most of the necrotic neurons corresponded to the post-synaptic side for the boutons including lamellar bodies. Necrotic neurons displayed a dense cytoplasmic matrix, an increase of polysomes and cisternal swelling in rough ER and in the Golgi apparatus. Membranous lamellar bodies were occasionally observed in the periphery of satellite glial cells, probably oligodendrocytes. In conclusion, a long lasting reduction of striatal dopamine caused by 6-OHDA might disturb the function around the synaptic area and the metabolic regulation in the post-synaptic striatal neuron, thus resulted in the appearance of rather chronic morphological alterations in those areas.

Hypokinesia produced by anterolateral hypothalamic 6-hydroxydopamine lesions and its reversal by some antiparkinson drugs.

Hypokinesia produced by stereotaxic microinjection of solutions of 6-hydroxydopamine into the anterolateral hypothalamus of male rats is accompanied by a generalized reduction in brain noradrenaline levels and a reduction of dopamine in the striatum and cerebral cortex. The hypokinesia is reversed by the putative dopamine-receptor agonists apomorphine, ET-495 and CB-154 as well as by the amino acids L-Dopa and m-tyrosine when administered in combination with the peripheral decarboxylase inhibitor Ro 4-4602. The relative importance of noradrenergic and dopaminergic systems in the mediation of the action of anti-akinesia drugs is discussed.