Sensory and autonomic innervation of the local tissues at traditional acupuncture point locations GB14, ST2 and ST6.

OBJECTIVE: To visualize and compare the sensory and autonomic innervation of the local tissues at the sites of different traditional acupuncture points in the rat forehead and face by histochemical examination. METHODS: GB14 (Yangbai), ST2 (Sibai) and ST6 (Jiache) were selected as the representative traditional acupuncture points in this study, and the local tissues at these sites were dissected in rats after perfusion followed by double or triple fluorescent histochemical staining. Here, calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH) and vesicular acetylcholine transporter (VAChT) were used to label the sensory, sympathetic and parasympathetic nerve fibers, respectively. RESULTS: The CGRP+ sensory, TH+ sympathetic and VAChT+ parasympathetic nerve fibers were simultaneously demonstrated in the local tissues at GB14, ST2 and ST6. Although the three kinds of nerve fibers ran in parallel or intermingled with each other, by the analysis from the view of three-dimensional reconstruction, it was clear that each of them distributed in an independent pattern to their corresponding target tissues including the blood vessels, hair follicles, arrector pili and subcutaneous muscles, as well as sebaceous glands. CONCLUSION: Our study demonstrated the sensory and autonomic innervation of the local tissues at GB14, ST2 and ST6, providing neurochemical evidence indicating that the CGRP+ sensory, TH+ sympathetic and VAChT+ parasympathetic nerve fibers form a neural network at these point locations that may respond to acupuncture stimulation.

The expression of PHOX2B in bone marrow and peripheral blood predicts adverse clinical outcome in non-high-risk neuroblastoma.

Paired-like homeobox 2B (PHOX2B) is a highly sensitive and specific biomarker for diagnosing neuroblastoma, as well as detecting minimal residual disease in neuroblastoma. The clinical significance of PHOX2B expression in bone marrow (BM) and peripheral blood (PB) samples of newly diagnosed patients with very low-, low- and intermediate-risk neuroblastoma remains unknown, to the best of our knowledge. The expression level of PHOX2B in paired BM and PB samples of patients with newly diagnosed neuroblastoma was validated using reverse transcription-quantitative polymerase chain reaction (RTqPCR). Among the 132 patients, 26 exhibited a positive PHOX2B expression BM (19.7%) and 11 in PB (8.3%) samples. PHOX2B was highly expressed in BM and PB samples from patients aged <18 months, with International Neuroblastoma Risk Group Staging System stages M and MS, 1p loss of heterozygosity, and high levels of lactate dehydrogenase, serum ferritin and neuron-specific enolase (p < 0.05). In all eligible patients, the 2-year event-free survival (EFS) and overall survival (OS) rates were 94.7 ± 2.0% and 97.7 ± 1.3%, respectively. However, the 2-year EFS rates were significantly decreased to 76.9 ± 8.3% and 63.6 ± 14.5% in patients with a positive PHOX2B expression in BM and PB samples, respectively (p < 0.05). Similarly, the 2-year OS rates were also decreased to 88.5 ± 6.3% and 81.8 ± 11.6% in patients with a positive PHOX2B expression in BM and PB samples, respectively (p < 0.05). In conclusion, a positive PHOX2B expression in BM and PB samples at diagnosis had a strong adverse prognostic effect on patients with non-high-risk neuroblastoma.

Behavioral profile in a Dctn1G71A knock-in mouse model of Perry disease.

Perry disease (Perry syndrome) is a rare, rapidly progressive, autosomal dominant neurodegenerative disease characterized by parkinsonism, depression/apathy, weight loss, and respiratory symptoms including central hypoventilation. It is caused by missense mutations (e.g. p.G71A) in the DCTN1 gene. We previously generated transgenic mice that expressed human DCTN1G71A mutant protein under the control of Thy1 promoter. These mice exhibited apathy-like behavior and parkinsonism. However, it is possible that this phenotype was due to a gene-dosage imbalance or transgene insertion position. To circumvent these potential caveats, we have generated a knock-in mouse model carrying a p.G71A mutation in Dctn1. Heterozygous Dctn1G71A and wild-type littermates were subjected to a battery of behavioral analyses. Furthermore, immunohistochemistry for tyrosine hydroxylase (TH) was performed on brain sections of these mice, and TH signal intensity in substantia nigral neurons was quantified. Dctn1G71A mice were immobile for longer than wild-type mice of the same age and sex in the tail-suspension test, revealing depressive characteristics. In addition, the beam-walking test and pole test detected motor deficits in Dctn1G71A female mice. Finally, immunostaining revealed a decrease in TH immunoreactivity in neurons of the substantia nigra in the Dctn1G71A mice. Collectively, heterozygous Dctn1G71A mice showed depression-like behavior, motor deficits, and a functional reduction in substantia nigral neurons, as judged by TH immunostaining, thereby exhibiting multiple features of Perry disease. Hence, this mouse model will be useful in elucidating pathological mechanisms of Perry disease and for developing novel therapeutic strategies against it.

Flavin-containing monooxygenase 1 deficiency promotes neuroinflammation in dopaminergic neurons in mice.

A growing body of evidence indicates an association between flavin-containing monooxygenase (FMO) and neurodegeneration, including Parkinson's disease (PD); however, the details of this association are unclear. We previously showed that the level of Fmo1 mRNA is decreased in an in vitro rotenone model of parkinsonism. To further explore the potential involvement of FMO1 deficiency in parkinsonism, we generated Fmo1 knockout (KO) mice and examined the survival of dopaminergic neurons and relative changes. Fmo1 KO mice exhibited loss of tyrosine hydroxylase-positive neurons, decreased levels of tyrosine hydroxylase and Parkin proteins, and increased levels of pro-inflammatory cytokines (IL1ß and IL6) in the nigrostriatal region. Moreover, the protein levels of PTEN induced kinase 1 (PINK1) and p62, and the Microtubule associated protein 1 light chain 3 (LC3)-II/I ratio were not significantly altered in Fmo1 KO mice (P > 0.05). FMO1 deficiency promotes neuroinflammation in dopaminergic neurons in mice, thus may plays a potential pathological role in dopaminergic neuronal loss. These findings may provide new insight into the pathogenesis of PD.

Physical exercise increases the production of tyrosine hydroxylase and CDNF in the spinal cord of a Parkinson's disease mouse model.

Previous research advocates that exercise is a non-pharmacological therapy for Parkinson's disease (PD). However, few studies have investigated the effects of exercise on central nervous system structures other than the nigrostriatal pathway by using PD animal models. This study investigated the effects of exercise on tyrosine hydroxylase (TH)- and cerebral dopamine neurotrophic factor (CDNF)-containing spinal-cord neurons. Male Swiss mice were divided into 4 groups: sedentary control (SEDCONT), exercise control (EXERCONT), sedentary Parkinson (SEDPD), and exercise Parkinson (EXERPD). The PD groups were submitted to a surgical procedure for stereotaxic bilateral injection of 6-hydroxydopamine into the striatum. TH- and CDNF-containing spinal-cord neurons were evaluated in all groups, using immunohistochemistry and western-blotting. TH content in the ventral horn differed notably between the SEDPD and EXERPD groups. CDNF content was highest in the EXERPD group. SEDPD and EXERPD groups differed the most, as shown by immunohistochemistry and western-blotting. The EXERPD group showed the most intense labeling in immunohistochemistry compared to the SEDCONT and EXERCONT groups. Therefore, we showed here that exercise increased the content of both TH and CDNF in the spinal-cord neurons of a bilateral PD mouse model. We may assume that the spinal cord is affected in a PD model, and therefore this central nervous system region deserves more attention from researchers dealing with PD.

Rapid immunohistological measurement of tyrosine hydroxylase in rat midbrain by near-infrared instrument-based detection.

We present a robust, fresh-frozen approach to immunohistochemistry (IHC), without committing the tissue to IHC via fixation and cryopreservation while maintaining long-term storage, using LiCor-based infrared (IR) quantification for sensitive assessment of TH in immunoreacted midbrain sections for quantitative comparison across studies. In fresh-frozen tissue stored up to 1 year prior to IHC reaction, we found our method to be highly sensitive to rotenone treatment in 3-month-old Sprague-Dawley rats, and correlated with a significant decline in rotarod latency-to-fall measurement by approximately 2.5 fold. The measured midbrain region revealed a 31 % lower TH signal when compared to control (p < 0.01 by t test, n = 5). Bivariate analysis of integrated TH counts versus rotarod latency-to-fall indicates a positive slope and modest but significant correlation of R2 = 0.68 (p < 0.05, n = 10). These results indicate this rapid, instrument-based quantification method by IR detection successfully quantifies TH levels in rat brain tissue, while taking only 5 days from euthanasia to data output. This approach also allows for the identification of multiple targets by IHC with the simultaneous performance of downstream molecular analysis within the same animal tissue, allowing for the use of fewer animals per study.

Conservation of mechanisms regulating emotional-like responses on spontaneous nicotine withdrawal in zebrafish and mammals.

BACKGROUND: Nicotine withdrawal syndrome is a major clinical problem. Animal models with sufficient predictive validity to support translation of pre-clinical findings to clinical research are lacking. AIMS: We evaluated the behavioural and neurochemical alterations in zebrafish induced by short- and long-term nicotine withdrawal. METHODS: Zebrafish were exposed to 1 mg/L nicotine for 2 weeks. Dependence was determined using behavioural analysis following mecamylamine-induced withdrawal, and brain nicotinic receptor binding studies. Separate groups of nicotine-exposed and control fish were assessed for anxiety-like behaviours, anhedonia and memory deficits following 2-60 days spontaneous withdrawal. Gene expression analysis using whole brain samples from nicotine-treated and control fish was performed at 7 and 60 days after the last drug exposure. Tyrosine hydroxylase (TH) immunoreactivity in pretectum was also analysed. RESULTS: Mecamylamine-precipitated withdrawal nicotine-exposed fish showed increased anxiety-like behaviour as evidenced by increased freezing and decreased exploration. 3H-Epibatidine labeled heteromeric nicotinic acethylcholine receptors (nAChR) significantly increased after 2 weeks of nicotine exposure while 125I-αBungarotoxin labeled homomeric nAChR remained unchanged. Spontaneous nicotine withdrawal elicited anxiety-like behaviour (increased bottom dwelling), reduced motivation in terms of no preference for the enriched side in a place preference test starting from Day 7 after withdrawal and a progressive decrease of memory attention (lowering discrimination index). Behavioural differences were associated with brain gene expression changes: nicotine withdrawn animals showed decreased expression of chrna 4 and chrna7 after 60 days, and of htr2a from 7 to 60 days.The expression of c-Fos was significantly increased at 7 days. Finally, Tyrosine hydroxylase (TH) immunoreactivity increased in dorsal parvocellular pretectal nucleus, but not in periventricular nucleus of posterior tuberculum nor in optic tectum, at 60 days after withdrawal. CONCLUSIONS: Our findings show that nicotine withdrawal induced anxiety-like behaviour, cognitive alterations, gene expression changes and increase in pretectal TH expression, similar to those observed in humans and rodent models.

Effect of High Fat and Fructo-Oligosaccharide Consumption on Immunoglobulin A in Saliva and Salivary Glands in Rats.

Consumption of indigestible dietary fiber increases immunoglobulin A (IgA) levels in saliva. The purpose of this study is to clarify the synergistic effect of the intake of a high amount of fats and indigestible dietary fiber on IgA levels in saliva and submandibular glands (SMG). Seven-week-old Wistar rats were fed a low-fat (60 g/kg) fiberless diet, low-fat fructo-oligosaccharide (FOS, 30 g/kg) diet, high-fat (220 g/kg) fiberless diet, or high-fat FOS diet for 70 days. The IgA flow rate of saliva (IgA FR-saliva) was higher in the low-fat FOS group than in the other groups (p < 0.05). Furthermore, the concentration of tyrosine hydroxylase (a marker of sympathetic nerve activation) in the SMG was higher in the low-fat FOS group (p < 0.05) and positively correlated with the IgA FR-saliva (rs = 0.68. p < 0.0001. n = 32) in comparison to that in the other groups. These findings suggest that during low-fat FOS intake, salivary IgA levels may increase through sympathetic nerve activation.

Tyrosine hydroxylase immunostaining in the central complex of dicondylian insects.

Dopamine acts as a neurohormone and neurotransmitter in the insect nervous system and controls a variety of physiological processes. Dopaminergic neurons also innervate the central complex (CX), a multisensory center of the insect brain involved in sky compass navigation, goal-directed locomotion and sleep control. To infer a possible influence of evolutionary history and lifestyle on the neurochemical architecture of the CX, we have studied the distribution of neurons immunoreactive to tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis. Analysis of representatives from 12 insect orders ranging from firebrats to flies revealed high conservation of immunolabeled neurons. One type of TH-immunoreactive neuron was found in all species studied. The neurons have somata in the pars intercerebralis, arborizations in the lateral accessory lobes, and axonal ramifications in the central body and noduli. In all pterygote species, a second type of tangential neuron of the upper division of the central body was TH-immunoreactive. The neurons have cell bodies near the calyces and arborizations in the superior protocerebrum. Both types of neuron showed species-specific variations in cell number and in the innervated areas outside and inside the CX. Additional neurons were found in only two taxa: one type of columnar neuron showed TH immunostaining in the water strider Gerris lacustris, but not in other Heteroptera, and a tritocerebral neuron innervating the protocerebral bridge was immunolabeled in Diptera. The data show largely taxon-specific variations of a common ground pattern of putatively dopaminergic neurons that may be commonly involved in state-dependent modulation of CX function.

miR­335 promotes ferroptosis by targeting ferritin heavy chain 1 in in vivo and in vitro models of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease characterized by the selective loss of dopaminergic neurons in the substantia nigra (SN). In a previous study, the authors demonstrated that ferritin heavy chain 1 (FTH1) inhibited ferroptosis in a model of 6­hydroxydopamine (6­OHDA)­induced PD. However, whether and how microRNAs (miRNAs/miRs) modulate FTH1 in PD ferroptosis is not yet well understood. In the present study, in vivo and in vitro models of PD induced by 6­OHDA were established. The results in vivo and in vitro revealed that the levels of the ferroptosis marker protein, glutathione peroxidase 4 (GPX4), and the PD marker protein, tyrosine hydroxylase (TH), were decreased in the model group, associated with a decreased FTH1 expression and the upregulation of miR­335. In both the in vivo and in vitro models, miR­335 mimic led to a lower FTH1 expression, exacerbated ferroptosis and an enhanced PD pathology. The luciferase 3'­untranslated region reporter results identified FTH1 as the direct target of miR­335. The silencing of FTH1 in 6­OHDA­stimulated cells enhanced the effects of miR­335 on ferroptosis and promoted PD pathology. Mechanistically, miR­335 enhanced ferroptosis through the degradation of FTH1 to increase iron release, lipid peroxidation and reactive oxygen species (ROS) accumulation, and to decrease mitochondrial membrane potential (MMP). On the whole, the findings of the present study reveal that miR­335 promotes ferroptosis by targeting FTH1 in in vitro and in vivo models of PD, providing a potential therapeutic target for the treatment of PD.

Extract of Polygala tenuifolia, Angelica tenuissima, and Dimocarpus longan Reduces Behavioral Defect and Enhances Autophagy in Experimental Models of Parkinson's Disease.

The 20% ethanol extract of Polygala tenuifolia, Angelica tenuissima, and Dimocarpus longan (WIN-1001X) was derived from a modified version of Korean traditional herbal formula 'Chungsimyeolda-tang' which has been used for the treatment of cerebrovascular disorders. The Parkinson's disease presents with impaired motor functions and loss of dopaminergic neurons. However, the treatment for Parkinson's disease is not established until now. This study aims to elucidate the therapeutic advantages of WIN-1001X on animal models of Parkinson's disease. WIN-1001X administration successfully relieved the Parkinsonism symptoms in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease mice tested by rota-rod and pole tests. The loss of tyrosine hydroxylase activities in substantia nigra and striatum was also attenuated by administration of WIN-1001X. In mice with sub-chronical MPTP injections, autophagy-related proteins, such as LC3, beclin-1, mTOR, and p62, were measured using the immunoblot assay. The results were favorable to induction of autophagy after the WIN-1001X administration. WIN-1001X treatment on 6-hydroxydopamine-injected rats also exhibited protective effects against striatal neuronal damage and loss of dopaminergic cells. Such protection is expected to be due to the positive regulation of autophagy by administration of WIN-1001X with confirmation both in vivo and in vitro. In addition, an active compound, onjisaponin B was isolated and identified from WIN-1001X. Onjisaponin B also showed significant autophagosome-inducing effect in human neuroblastoma cell line. Our study suggests that relief of Parkinsonism symptoms and rescue of tyrosine hydroxylase activity in dopaminergic neurons are affected by autophagy enhancing effect of WIN-1001X which the onjisaponin B is one of the major components of activity.

Olfactory mucosa stem cells delivery via nasal route: a simple way for the treatment of Parkinson disease.

Finding a simple and effective way for transferring cells to the brain lesion site with minimum side effects mounts a challenge in cell therapy. Cell delivery via nasal route using the bypassing the blood-brain barrier (BBB) property is a simple and non-invasive strategy without serious complications such as trauma. Therefore, it is a suitable technique to treat neurodegenerative disorders like Parkinson's disease (PD). Olfactory ectomesenchymal stem cells (OE-MSCs) located in the lamina propria of olfactory mucosa could be differentiated into dopaminergic neurons under in vitro and in vivo conditions. Thus, OE-MSCs represent a good source of Parkinson's stem cell-based therapy. In this research, we studied thirty male rats (n = 10 in each group) in three control (Ctl), lesion (LE), and intranasal administration (INA) groups to investigate the therapeutic effect of intranasal injection of OE-MSCs in the Parkinson's animal models. To do so, we examined the homing variation of OE-MSCs in different brain regions such as olfactory bulb (OB), cortex, striatum (Str), hippocampus (HPC), and substantia nigra (SN). The results of real-time PCR and immunohistochemistry (IHC) analysis showed the expression of dopaminergic neuron markers such as PITX3, PAX2, PAX5 (as dopaminergic neurons markers), tyrosine hydroxylase (TH), and dopamine transporter (DAT) 2 months after INA of 1 × 106 OE-MSCs. The results confirmed that IN OE-MSCs delivery into the central nervous system (CNS) was powerful enough to improve the behavioral functions in the animal models of PD.

Projections from the dorsomedial division of the bed nucleus of the stria terminalis to hypothalamic nuclei in the mouse.

As stressful environment is a potent modulator of feeding, we seek in the present work to decipher the neuroanatomical basis for an interplay between stress and feeding behaviors. For this, we combined anterograde and retrograde tracing with immunohistochemical approaches to investigate the patterns of projections between the dorsomedial division of the bed nucleus of the stria terminalis (BNST), well connected to the amygdala, and hypothalamic structures such as the paraventricular (PVH) and dorsomedial (DMH), the arcuate (ARH) nuclei and the lateral hypothalamic areas (LHA) known to control feeding and motivated behaviors. We particularly focused our study on afferences to proopiomelanocortin (POMC), agouti-related peptide (AgRP), melanin-concentrating-hormone (MCH) and orexin (ORX) neurons characteristics of the ARH and the LHA, respectively. We found light to intense innervation of all these hypothalamic nuclei. We particularly showed an innervation of POMC, AgRP, MCH and ORX neurons by the dorsomedial and dorsolateral divisions of the BNST. Therefore, these results lay the foundation for a better understanding of the neuroanatomical basis of the stress-related feeding behaviors.

Intrastriatal administration of coenzyme Q10 enhances neuroprotection in a Parkinson's disease rat model.

Parkinson's disease is a neurodegenerative disorder, and no treatment has been yet established to prevent disease progression. Coenzyme Q10, an antioxidant, has been considered a promising neuroprotective agent; however, conventional oral administration provides limited efficacy due to its very low bioavailability. In this study, we hypothesised that continuous, intrastriatal administration of a low dose of Coenzyme Q10 could effectively prevent dopaminergic neuron degeneration. To this end, a Parkinson's disease rat model induced by 6-hydroxydopamine was established, and the treatment was applied a week before the full establishment of this disease model. Behavioural tests showed a dramatically decreased number of asymmetric rotations in the intrastriatal Coenzyme Q10 group compared with the no treatment group. Rats with intrastriatal Coenzyme Q10 exposure also exhibited a larger number of dopaminergic neurons, higher expression of neurogenetic and angiogenetic factors, and less inflammation, and the effects were more prominent than those of orally administered Coenzyme Q10, although the dose of intrastriatal Coenzyme Q10 was 17,000-times lower than that of orally-administered Coenzyme Q10. Therefore, continuous, intrastriatal delivery of Coenzyme Q10, especially when combined with implantable devices for convection-enhanced delivery or deep brain stimulation, can be an effective strategy to prevent neurodegeneration in Parkinson's disease.

Differences in behavior between surface and cave Astyanax mexicanus may be mediated by changes in catecholamine signaling.

Astyanax mexicanus is a teleost fish that is in the process of allopatric speciation. Ancestral Astyanax are found in surface rivers and derived blind forms are found in cave systems. Adaptation to life in nutrient poor caves without predation includes the evolution of enhanced food seeking behaviors and loss of defensive responses. These behavioral adaptations may be mediated by changes in catecholaminergic control systems in the brain. We examined the distribution of tyrosine hydroxylase, a conserved precursor for the synthesis of the catecholamines dopamine and noradrenaline, in the brains of surface and cave Astyanax using immunohistochemistry. We found differences in tyrosine hydroxylase staining in regions that are associated with nonvisual sensory perception, motor control, endocrine release, and attention. These differences included significant increases in the diameters of tyrosine hydroxylase immunoreactive soma in cave Astyanax in the olfactory bulb, basal telencephalon, preoptic nuclei, ventral thalamus, posterior tuberculum, and locus coeruleus. These increases in modulation by dopamine and noradrenaline likely indicate changes in behavioral control that underlie adaptations to the cave environment.

Colocalized neurotransmitters in the hindbrain cooperate in adaptation to chronic hypernatremia.

Chronic hypernatremia activates the central osmoregulatory mechanisms and inhibits the function of the hypothalamic-pituitary-adrenal (HPA) axis. Noradrenaline (NE) release into the periventricular anteroventral third ventricle region (AV3V), the supraoptic (SON) and hypothalamic paraventricular nuclei (PVN) from efferents of the caudal ventrolateral (cVLM) and dorsomedial (cDMM) medulla has been shown to be essential for the hypernatremia-evoked responses and for the HPA response to acute restraint. Notably, the medullary NE cell groups highly coexpress prolactin-releasing peptide (PrRP) and nesfatin-1/NUCB2 (nesfatin), therefore, we assumed they contributed to the reactions to chronic hypernatremia. To investigate this, we compared two models: homozygous Brattleboro rats with hereditary diabetes insipidus (DI) and Wistar rats subjected to chronic high salt solution (HS) intake. HS rats had higher plasma osmolality than DI rats. PrRP and nesfatin mRNA levels were higher in both models, in both medullary regions compared to controls. Elevated basal tyrosine hydroxylase (TH) expression and impaired restraint-induced TH, PrRP and nesfatin expression elevations in the cVLM were, however, detected only in HS, but not in DI rats. Simultaneously, only HS rats exhibited classical signs of chronic stress and severely blunted hormonal reactions to acute restraint. Data suggest that HPA axis responsiveness to restraint depends on the type of hypernatremia, and on NE capacity in the cVLM. Additionally, NE and PrRP signalization primarily of medullary origin is increased in the SON, PVN and AV3V in HS rats. This suggests a cooperative action in the adaptation responses and designates the AV3V as a new site for PrRP's action in hypernatremia.

Differences in the number of oxytocin, vasopressin, and tyrosine hydroxylase cells in brain regions associated with mating among great, midday, and Mongolian gerbils.

Neurotransmitters, such as oxytocin (OT), vasopressin (AVP), and dopamine (DA), within the mesolimbic system have deeply conserved roles in regulating mating-related behaviors. However, comparative studies among monogamous and polygamous animals focus mainly on Microtus; very little research has been done in gerbils. Here, we measured body weight, body length, tail length, serum hormone concentrations, and the immunoreactive (ir)-cells of OT, AVP, and tyrosine hydroxylase (TH) in the brain of the polygamous great gerbil (Rhombomys opimus), midday gerbil (Meriones meridianus), and monogamous Mongolian gerbil (Meriones unguiculatus). Body weight, body length, tail length, and serum AVP concentrations were greater in the great gerbil than in the midday gerbil and Mongolian gerbil. The number of OT and AVP cells in the para ventricular nucleus (PVN) and supra optic nucleus (SON) of the hypothalamus were greater in the Mongolian gerbil than in the great gerbil and midday gerbil. Similarly, the number of TH cells in the PVN, medial preoptic area (MPOA), and ventral tegmental area (VTA) was greater in the Mongolian gerbil than in the great gerbil and midday gerbil. To summarize, the number of OT and AVP cells in the PVN and SON and TH cells in the PVN, MPOA, and VTA in the monogamous Mongolian gerbil are greater than those in the great gerbil and midday gerbil.

Tyrosinemia Type 1 and symptoms of ADHD: Biochemical mechanisms and implications for treatment and prognosis.

Hereditary tyrosinemia Type 1 (HT-1) is a rare metabolic disease where the enzyme catalyzing the final step of tyrosine breakdown is defect, leading to accumulation of toxic metabolites. Nitisinone inhibits the degradation of tyrosine and thereby the production of harmful metabolites, however, the concentration of tyrosine also increases. We investigated the relationship between plasma tyrosine concentrations and cognitive functions and how tyrosine levels affected enzyme activities of human tyrosine hydroxylase (TH) and tryptophan hydroxylase 2 (TPH2). Eight Norwegian children between 6 and 18 years with HT-1 were assessed using questionnaires measuring Attention Deficit Hyperactivity Disorder (ADHD)-symptoms and executive functioning. Recent and past levels of tyrosine were measured and the enzyme activities of TH and TPH2 were studied at conditions replicating normal and pathological tyrosine concentrations. We observed a significant positive correlation between mean tyrosine levels and inattention symptoms. While TH exhibited prominent substrate inhibition kinetics, TPH2 activity also decreased at elevated tyrosine levels. Inhibition of both enzymes may impair syntheses of dopamine, noradrenaline, and serotonin in brain tissue. Inattention in treated HT-1 patients may be related to decreased production of these monoamines. Our results support recommendations of strict guidelines on plasma tyrosine levels in HT-1. ADHD-related deficits, particularly inattention, should be monitored in HT-1 patients to determine whether intervention is necessary.

Quantitative whole-brain 3D imaging of tyrosine hydroxylase-labeled neuron architecture in the mouse MPTP model of Parkinson's disease.

Parkinson's disease (PD) is a basal ganglia movement disorder characterized by progressive degeneration of the nigrostriatal dopaminergic system. Immunohistochemical methods have been widely used for characterization of dopaminergic neuronal injury in animal models of PD, including the MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model. However, conventional immunohistochemical techniques applied to tissue sections have inherent limitations with respect to loss of 3D resolution, yielding insufficient information on the architecture of the dopaminergic system. To provide a more comprehensive and non-biased map of MPTP-induced changes in central dopaminergic pathways, we used iDISCO immunolabeling, light-sheet fluorescence microscopy (LSFM) and deep-learning computational methods for whole-brain three-dimensional visualization and automated quantitation of tyrosine hydroxylase (TH)-positive neurons in the adult mouse brain. Mice terminated 7 days after acute MPTP administration demonstrated widespread alterations in TH expression. Compared to vehicle controls, MPTP-dosed mice showed a significant loss of TH-positive neurons in the substantia nigra pars compacta and ventral tegmental area. Also, MPTP dosing reduced overall TH signal intensity in basal ganglia nuclei, i.e. the substantia nigra, caudate-putamen, globus pallidus and subthalamic nucleus. In contrast, increased TH signal intensity was predominantly observed in limbic regions, including several subdivisions of the amygdala and hypothalamus. In conclusion, mouse whole-brain 3D imaging is ideal for unbiased automated counting and densitometric analysis of TH-positive cells. The LSFM-deep learning pipeline tracked brain-wide changes in catecholaminergic pathways in the MPTP mouse model of PD, and may be applied for preclinical characterization of compounds targeting dopaminergic neurotransmission.

Effects of sleep disruption on stress, nigrostriatal markers, and behavior in a chronic/progressive MPTP male mouse model of parkinsonism.

Sleep complaints are an early clinical symptom of neurodegenerative disorders. Patients with Parkinson's disease (PD) experience sleep disruption (SD). The objective of this study was to determine if preexisting, chronic SD leads to a greater loss of tyrosine hydroxylase (TH) within the striatum and the substantia nigra following chronic/progressive exposure with the neurotoxin, 1-methyl-2-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Male mice underwent chronic SD for 4 weeks, then injected with vehicle (VEH) or increasing doses of MPTP for 4 weeks. There was a significant decrease in the plasma corticosterone levels in the MPTP group, an increase in the SD group, and a return to the VEH levels in the SD+MPTP group. Protein expression levels for TH in the striatum (terminals) and substantia nigra pars compacta (dopamine [DA] cell counts) revealed up to a 78% and 38% decrease, respectively, in the MPTP and SD+MPTP groups compared to their relevant VEH and SD groups. DA transporter protein expression increased in the striatum in the MPTP versus VEH group and in the SN/midbrain between the SD+MPTP and the VEH group. There was a main effect of MPTP on various gait measures (e.g., braking) relative to the SD or VEH groups. In the SD+MPTP group, there were no differences compared to the VEH group. Thus, SD, prior to administration of MPTP, has effects on serum corticosterone and gait but more importantly does not potentiate greater loss of TH within the nigrostriatal pathway compared to the MPTP group, suggesting that in PD patients with SD, there is no exacerbation of the DA cell loss.