Pancreatic acinar cells utilize tyrosine to synthesize L-dihydroxyphenylalanine.

The pancreatic ß cells can synthesize dopamine by taking L-dihydroxyphenylalanine, but whether pancreatic acinar cells synthesize dopamine has not been confirmed. By means of immunofluorescence, the tyrosine hydroxylase -immunoreactivity and aromatic amino acid decarboxylase (AADC)- immunoreactivity were respectively observed in pancreatic acinar cells and islet ß cells. Treatment with L-dihydroxyphenylalanine, not tyrosine, caused the production of dopamine in the incubation of INS-1 cells (rat islet ß cell line) and primary isolated islets, which was blocked by AADC inhibitor NSD-1015. However, only L-dihydroxyphenylalanine, but not dopamine, was detected when AR42J cells (rat pancreatic acinar cell line) were treated with tyrosine, which was blocked by tyrosine hydroxylase inhibitor AMPT. Dopamine was detected in the coculture of INS-1 cells with AR42J cells after treatment with tyrosine. In an in vivo study, pancreatic juice contained high levels of L-dihydroxyphenylalanine and dopamine. Both L-dihydroxyphenylalanine and dopamine accompanied with pancreatic enzymes and insulin in the pancreatic juice were all significantly increased after intraperitoneal injection of bethanechol chloride and their increases were all blocked by atropine. Inhibiting TH with AMPT blocked bethanechol chloride-induced increases in L-dihydroxyphenylalanine and dopamine, while inhibiting AADC with NSD-1015 only blocked the dopamine increase. Bilateral subdiaphragmatic vagotomy of rats leads to significant decreases of L-dihydroxyphenylalanine and dopamine in pancreatic juice. These results suggested that pancreatic acinar cells could utilize tyrosine to synthesize L-dihydroxyphenylalanine, not dopamine. Islet ß cells only used L-dihydroxyphenylalanine, not tyrosine, to synthesize dopamine. Both L-dihydroxyphenylalanine and dopamine were respectively released into the pancreatic duct, which was regulated by the vagal cholinergic pathway. The present study provides important evidences for the source of L-dihydroxyphenylalanine and dopamine in the pancreas.

Exploring the Mechanism on the Medullary Visceral Zone Inhibiting the Cholinergic Anti-inflammatory Pathway Induced by Sepsis.

Inflammatory storm is an important pathological mechanism of multiple organ dysfunction, and it is associated with most deaths in septic patients, deserving to be studied. Recent findings have confirmed that the Medullary Visceral Zone (MVZ) regulates inflammation and immunity through the cholinergic anti-inflammatory pathway (CAP), but how sepsis affects the MVZ and leads to uncontrolled inflammation remain unclear. The current study reported that sepsis induced MVZ to inhibit CAP which underlies the inflammation storm. Our studies have shown that the rat models of sepsis prepared by cecal ligation and puncture had a higher inflammatory level, higher mortality, and higher Murine Sepsis Score. In septic rats, some indicators of heart rate variability (HRV) such as SDNN, HF band, RMSSD, SD1, and SD2 significantly reduced. In MVZ of septic rats, many cholinergic and catecholaminergic neurons showed apoptotic, with low expressions of tyrosine hydroxylase and choline acetyltransferase. The α7nAChR agonist GTS-21 can improve these pathologies, while the α7nAChR antagonist MLA is the opposite. Our study demonstrates for the first time that cholinergic and catecholaminergic neurons in MVZ went through significant apoptosis and inactiveness in sepsis, which contributes to the inhibition of CAP and acceleration of the inflammation storm in early sepsis. Intervening with CAP has a significant effect on the activity and apoptosis of MVZ neurons while altering systemic inflammation and immunity; in addition, for the first time, we confirmed that some indicators of HRV such as SDNN, HF band, RMSSD, SD1, and SD2 can reflect the activity of CAP, but the CAP interference had little effect on these indicators.

Multi-antigen DNA vaccine delivered by polyethylenimine and Salmonella enterica in neuroblastoma mouse model.

Neuroblastoma is an example of a difficult-to-treat tumor with high incidence of relapse. DNA vaccination could be applied as a relapse prophylactic option for patients with high-risk neuroblastoma. Its efficacy depends directly on a target antigen of choice and a delivery method. Three neuroblastoma-associated antigens (tyrosine hydroxylase, Survivin, PHOX2B) and two delivery methods were investigated. Our data suggest that antigen PHOX2B is a more immunogenic target that induces cellular immune response and tumor regression more effectively than tyrosine hydroxylase and Survivin. Immunogenicity testing revealed that the delivery of DNA vaccine by Salmonella enterica was accompanied by a stronger immune response (cytotoxicity and IFNγ production) than that by DNA-polyethylenimine conjugate. Nevertheless, intramuscular immunization with PEI led to higher decrease of tumor volume compared to that after oral gavage with Salmonella vaccine.

Long-term post-mortem studies following neurturin gene therapy in patients with advanced Parkinson's disease.

We performed post-mortem studies on two patients with advanced Parkinson's disease 8 and10 years following AAV2-neurturin (CERE120) gene therapy, the longest post-mortem trophic factor gene therapy cases reported to date. CERE120 was delivered to the putamen bilaterally in one case (10 years post-surgery), and to the putamen plus the substantia nigra bilaterally in the second (8 years post-surgery). In both patients there was persistent, albeit limited, neurturin expression in the putamen covering ∼3-12% of the putamen. In the putamen, dense staining of tyrosine hydroxylase-positive fibres was observed in areas that contained detectable neurturin expression. In the substantia nigra, neurturin expression was detected in 9.8-18.95% and 22.02-39% of remaining melanin-containing neurons in the patient with putamenal and combined putamenal and nigral gene delivery, respectively. Melanized neurons displayed intense tyrosine hydroxylase and RET proto-oncogene expression in nigral neurons in the patient where CERE120 was directly delivered to the nigra. There was no difference in the degree of Lewy pathology in comparison to untreated control patients with Parkinson's disease, and α-synuclein aggregates were detected in neurons that also stained for neurturin, RET, and tyrosine hydroxylase. These changes were not associated with antiparkinsonian benefits likely due to the limited neurturin expression. This study provides the longest term evidence of persistent transgene expression following gene delivery to the CNS and the first human results when targeting both the terminal fields in the putamen as well as the originating nigral neurons.

Innervation of the Epithelium and Lamina Propria of the Urethra of the Female Rat.

The aim of this study was to characterize the number, type and distribution of immunochemically identified nerves in epithelium and lamina propria of the female rat urethra. Urethras from female Sprague-Dawley rats (n = 12) were fixed, frozen and sectioned (8 µm). Standard immunohistochemical techniques were used to identify putative nerves using the following antibodies: calcitonin gene related peptide (cgrp), neuronal nitric oxide synthase (nNos), tyrosine hydroxylase (TH) and vesicular acetylcholine transporter (vacht). The number, distribution and characteristics of all immunoreactive (IR) structures adjacent to the urethral epithelium and in the lamina propria was assessed. In the bladder, few cgrp-IR and vacht-IR fibers were associated with the urothelium or suburothelium of the lateral wall. In contrast, large numbers of vacht-IR, nNos-IR and cgrp-IR fibers were found close to the epithelium and subepithelium of the bladder neck and throughout the urethra. The number of cgrp-IR fibers was significantly higher in the urethra in comparison with the bladder neck. A population of undescribed cgrp-IR cells associated with the bladder neck and proximal urethra has been characterized. Each of these cells appears to be associated with a nerve fiber. In the distal urethra, the number of peptidergic fibers penetrating the epithelium was significantly higher than the rest of the urethra. Clearly, this study has revealed a highly complex and heterogeneous network of putative afferent nerves fibers along the length of the urethra. These structural specializations need to be taken into account when probing the different functions of the urethra. Anat Rec, 302:201-214, 2019. © 2018 Wiley Periodicals, Inc.

Reduction of Total Brain and Cerebellum Volumes Associated With Neuronal Autoantibodies in Patients With APECED.

Context: In autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), autoantibodies (AutoAbs) labeling brain neurons were reported; conversely, brain MRI alterations associated with these AutoAbs were never reported. Objectives: To describe brain alterations in APECED and to correlate them with AutoAbs against glutamic acid decarboxylase (GAD), tyrosine hydroxylase (TH), and 5-tryptophan hydroxylase (5-HT) neurons. Design and Participants: Fourteen Sardinian patients with APECED and age-matched control subjects were recruited for MRI analysis and blood sampling to detect AutoAbs to GAD, TH, and 5-HT neurons by using rat brain sections. The majority of patients (n = 12) were investigated for AutoAbs a decade earlier, and 7 of 12 were positive for AutoAbs to GAD and TH neurons. Main Outcomes: Patients with APECED had smaller cerebellum and gray matter volumes, with a ventricular enlargement and a total cerebrospinal fluid (CSF) increase, compared with controls (P < 0.01). In 11 of 14 patients, brain abnormalities were associated with AutoAbs to GAD or TH neurons (titer 1:100 to 15,000) that had persisted for 10 years in 7 of 11 patients. AutoAbs to 5-HT neurons were revealed in all patients with AutoAbs to TH neurons. A decrease in whole brain and cerebellum volumes (P = 0.028) was associated with AutoAbs to GAD neurons, and a CSF increase was associated with AutoAbs to GAD and TH/5-HT neurons (P < 0.05). HLA alleles did not appear to be involved in neuronal autoimmunity. Conclusions: Brain alterations and neuronal AutoAbs were observed in 78.6% of Sardinian patients with APECED, suggesting a brain autoimmune reaction. Prolonged clinical follow-up must be conducted for the possible appearance of clinical neurologic consequences.

Co-expression of IL-15 enhances anti-neuroblastoma effectivity of a tyrosine hydroxylase-directed DNA vaccination in mice.

Long-term survival of high-risk neuroblastoma (NB) patients still remains under 50%. Here, we report the generation, in vitro characterization and anti-tumor effectivity of a new bicistronic xenogenic DNA vaccine encoding tyrosine hydroxylase (TH) that is highly expressed in NB tumors, and the immune stimulating cytokine interleukin 15 (IL-15) that induces cytotoxic but not regulatory T cells. The DNA sequences of TH linked to ubiquitin and of IL-15 were integrated into the bicistronic expression vector pIRES. Successful production and bioactivity of the vaccine-derived IL-15- and TH protein were shown by ELISA, bioactivity assay and western blot analysis. Further, DNA vaccine-driven gene transfer to the antigen presenting cells of Peyer's patches using attenuated Salmonella typhimurium that served as oral delivery system was shown by immunofluorescence analysis. The anti-tumor effect of the generated vaccine was evaluated in a syngeneic mouse model (A/J mice, n = 12) after immunization with S. typhimurium (3× prior and 3× after tumor implantation). Importantly, TH-/IL-15-based DNA vaccination resulted in an enhanced tumor remission in 45.5% of mice compared to controls (TH (16.7%), IL-15 (0%)) and reduced spontaneous metastasis (30.0%) compared to controls (TH (63.6%), IL-15 (70.0%)). Interestingly, similar levels of tumor infiltrating CD8+ T cells were observed among all experimental groups. Finally, co-expression of IL-15 did not result in elevated regulatory T cell levels in tumor environment measured by flow cytometry. In conclusion, co-expression of the stimulatory cytokine IL-15 enhanced the NB-specific anti-tumor effectivity of a TH-directed vaccination in mice and may provide a novel immunological approach for NB patients.

Post-treatment with PT302, a long-acting Exendin-4 sustained release formulation, reduces dopaminergic neurodegeneration in a 6-Hydroxydopamine rat model of Parkinson's disease.

We previously demonstrated that pretreatment with Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, reduces 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) -mediated dopaminergic neurodegeneration. The use of GLP-1 or Exendin-4 for Parkinson's disease (PD) patients is limited by their short half-lives. The purpose of this study was to evaluate a new extended release Exendin-4 formulation, PT302, in a rat model of PD. Subcutaneous administration of PT302 resulted in sustained elevations of Exendin-4 in plasma for >20 days in adult rats. To define an efficacious dose within this range, rats were administered PT302 once every 2 weeks either before or following the unilaterally 6-hydroxydopamine lesioning. Pre- and post-treatment with PT302 significantly reduced methamphetamine-induced rotation after lesioning. For animals given PT302 post lesion, blood and brain samples were collected on day 47 for measurements of plasma Exendin-4 levels and brain tyrosine hydroxylase immunoreactivity (TH-IR). PT302 significantly increased TH-IR in the lesioned substantia nigra and striatum. There was a significant correlation between plasma Exendin-4 levels and TH-IR in the substantia nigra and striatum on the lesioned side. Our data suggest that post-treatment with PT302 provides long-lasting Exendin-4 release and reduces neurodegeneration of nigrostriatal dopaminergic neurons in a 6-hydroxydopamine rat model of PD at a clinically relevant dose.

Acute Neuroinflammatory Response in the Substantia Nigra Pars Compacta of Rats after a Local Injection of Lipopolysaccharide.

Models of Parkinson's disease with neurotoxins have shown that microglial activation does not evoke a typical inflammatory response in the substantia nigra, questioning whether neuroinflammation leads to neurodegeneration. To address this issue, the archetypal inflammatory stimulus, lipopolysaccharide (LPS), was injected into the rat substantia nigra. LPS induced fever, sickness behavior, and microglial activation (OX42 immunoreactivity), followed by astrocyte activation and leukocyte infiltration (GFAP and CD45 immunoreactivities). During the acute phase of neuroinflammation, pro- and anti-inflammatory cytokines (TNF-α, IL-1ß, IL-6, IL-4, and IL-10) responded differentially at mRNA and protein level. Increased NO production and lipid peroxidation occurred at 168 h after LPS injection. At this time, evidence of neurodegeneration could be seen, entailing decreased tyrosine hydroxylase (TH) immunoreactivity, irregular body contour, and prolongation discontinuity of TH+ cells, as well as apparent phagocytosis of TH+ cells by OX42+ cells. Altogether, these results show that LPS evokes a typical inflammatory response in the substantia nigra that is followed by dopaminergic neurodegeneration.

Role of catalpol in ameliorating the pathogenesis of experimental autoimmune encephalomyelitis by increasing the level of noradrenaline in the locus coeruleus.

The endogenous neurotransmitter, noradrenaline, exerts anti-inflammatory and neuroprotective effects in vivo and in vitro. Reduced noradrenaline levels results in increased inflammation and neuronal damage. The primary source of noradrenaline in the central nervous system is tyrosine hydroxylase (TH)­positive neurons, located in the locus coeruleus (LC). TH is the rate­limiting enzyme for noradrenaline synthesis; therefore, regulation of TH protein expression and intrinsic enzyme activity represents the central means for controlling the synthesis of noradrenaline. Catalpol is an iridoid glycoside purified from Rehmannia glutinosa Libosch, which exerts a neuroprotective effect in multiple sclerosis (MS). The present study used an experimental mouse model of autoimmune encephalomyelitis to verify the neuroprotective effects of catalpol. Significant improvements in the clinical scores were observed in catalpol­treated mice. Furthermore, catalpol increased TH expression and increased noradrenaline levels in the spinal cord. In primary cultures, catalpol exerted a neuroprotective effect in rat LC neurons by increasing the noradrenaline output. These results suggested that drugs targeting LC survival and function, including catalpol, may be able to benefit patients with MS.

Silencing tyrosine hydroxylase retards depression of immunocompetence of Litopenaeus vannamei under hypothermal stress.

Tyrosine hydroxylase (TH), the first and rate-limiting step in the synthesis of catecholamines, is required in catecholamine synthesis of the neuroendocrine regulatory network against stress in shrimp. The immunocompetence, catecholamine biosynthesis, and carbohydrate metabolites were evaluated in Litopenaeus vannamei received L. vannamei TH (LvTH) double-stranded (ds)RNA, diethyl pyrocarbonate-water, or non-targeted dsRNA for 3 days then transferred from 28 to 20 or 28 °C. The immunocompetence of LvTH-depleted shrimp held at 28 °C was promoted, and those were downregulated under hypothermal stress and revealed higher level than the other two dsRNA treatments. Meanwhile, the decrease of catecholamine biosynthesis was observed in LvTH-depleted shrimp held at 28 °C, and those were elevated under hypothermal stress and revealed lower levels, compared to two dsRNA treatments. The reduced carbohydrate metabolites was observed in LvTH-depleted shrimp held at 28 °C, and those were upregulated under hypothermal stress and showed lower levels than the other two dsRNA treatments. It was therefore concluded that LvTH-depleted shrimp revealed enhanced immunocompetence and reduced carbohydrate metabolites when exposed to a hypothermal stress condition, and in the meantime, even though catecholamine biosynthesis was downregulated, no significant difference was observed in DA or NE levels.

Regional analysis and genetic association of nigrostriatal degeneration in Lewy body disease.

BACKGROUND: A number of genetic loci are associated with risk for Parkinson's disease (PD) based on genome-wide association studies; however, the relationship between genetic variants and nigrostriatal degeneration, which is the structural correlate of parkinsonism, has not been reported. OBJECTIVES: We quantified nigrostriatal dopaminergic integrity with image analysis of putaminal tyrosine hydroxylase immunoreactivity in 492 brains with Lewy body disease and used this pathologic endophenotype to explore possible association with PD genetic variants. METHODS: The study cases had Lewy-related pathology and variable degrees of nigrostriatal degeneration. They were assigned to one of the following clinical subgroups according to their predominant clinical syndrome: parkinsonism-predominant, parkinsonism+dementia, and dementia-predominant. In addition to putaminal tyrosine hydroxylase immunoreactivity, semiquantitative scoring was used to assess substantia nigra neuronal loss. A total of 29 PD genetic risk variants were genotyped on each case. RESULTS: When compared with controls, tyrosine hydroxylase immunoreactivity was reduced in Lewy body cases in the dorsolateral (79%) and ventromedial (57%) putamen. The dorsolateral region was better preserved in dementia-predominant cases than in cases with parkinsonism. Dorsolateral putaminal tyrosine hydroxylase immunoreactivity correlated with neuronal loss in the ventrolateral substantia nigra. Genetic analyses showed no significant association of PD risk variants with putaminal tyrosine hydroxylase immunoreactivity. CONCLUSIONS: The results confirm regional differences in putaminal dopaminergic degeneration and vulnerability of nigrostriatal pathway in Lewy body disorders with parkinsonism. The lack of association with PD genetic risk variants suggests that they may not be associated with quantitative endophenotypes of nigrostriatal degeneration, but more likely related to the risk of disease per se. © 2017 International Parkinson and Movement Disorder Society.

Partial rescue of neuropathology in the murine model of PKU following administration of recombinant phenylalanine ammonia lyase (pegvaliase).

Pegylated recombinant phenylalanine ammonia lyase (pegvaliase) is an enzyme substitution therapy being evaluated for the treatment of phenylketonuria (PKU). PKU is characterized by elevated plasma phenylalanine, which is thought to lead to a deficiency in monoamine neurotransmitters and ultimately, neurocognitive dysfunction. A natural history evaluation in a mouse model of PKU demonstrated a profound decrease in tyrosine hydroxylase (TH) immunoreactivity in several brain regions, beginning at 4weeks of age. Following treatment with pegvaliase, the number of TH positive neurons was increased in several brain regions compared to placebo treated ENU2 mice.

Inmunosenescencia prematura en ratones con una deficiencia en la síntesis de catecolaminas. Efecto del ambiente social / Premature immunosenescence in catecholamines syntesis deficient mice. Effect of social environment

Introducción. La salud depende del buen funcionamiento de los sistemas homeostáticos (el nervioso, endocrino e inmunitario) y de la adecuada comunicación entre ellos. Se ha comprobado que el estado funcional y redox del sistema inmunitario es un excelente marcador de salud, y que una inmunosenescencia prematura supone una menor esperanza de vida. Dado que las catecolaminas modulan la funcionalidad de las células inmunitarias, la alteración en su síntesis podría contribuir a esa inmunosenescencia. Entre las estrategias que se pueden utilizar para controlarla está el ambiente social. Objetivo. Comprobar si una haploinsuficiencia de la tirosina hidroxilasa (TH), enzima limitante de la síntesis de catecolaminas, generaría una inmunosenescencia prematura, y si es posible la modulación de esta por el ambiente social. Material y métodos. Se usaron ratones machos ICR-CD1 adultos (9±1 meses) hemizigotos (HZ) para la tirosina hidroxilasa (TH-HZ) y controles (WT), que fueron distribuidos en cuatro subgrupos: WT>50% (en la jaula, la proporción de WT fue mayor al 50%), WT<50%, TH-HZ<50% y TH-HZ>50%. En leucocitos peritoneales se valoró la fagocitosis, quimiotaxis y linfoproliferación en presencia de lipopolisacárido. También, la actividad de las enzimas antioxidantes glutatión reductasa y glutatión peroxidasa, y el cociente glutatión oxidado/glutatión reducido. Resultados. Los TH-HZ>50% presentaron, en leucocitos, una funcionalidad y estado redox deteriorados respecto a WT>50 y similar a ratones viejos. Sin embargo, los TH-HZ<50% mostraron valores similares a los WT<50%. Conclusión. Una haploinsuficiencia de la enzima TH provoca una inmunosenescencia prematura, la cual puede ser compensada por la convivencia con un número apropiado de animales WT (AU)

Introduction. Healthy state depends on the appropriate function of the homeostatic systems (nervous, endocrine and immune systems) and the correct communication between them. The functional and redox state of the immune system is an excellent marker of health, and animals with premature immunosenescence show a shorter lifespan. Since catecholamines modulate the function of immune cells, the alteration in their synthesis could provoke immunosenescence. The social environment could be a strategy for modulating this immunosenescence. Aim. To determine if an haploinsufficiency of tyrosine hydroxylase (TH), the limiting enzyme of synthesis of catecholamines, may produce a premature immunosenescence and if this immunosenescence could be modulated by the social environment. Materials and methods. Adult (9±1 months) male ICR-CD1 mice with deletion of a single allele (hemi-zygotic: HZ) of the tyrosine hydroxylase enzyme (TH-HZ) and wild-type (WT) mice were used. Animals were housed in four subgroups: WT>50% (in the cage, the proportion of WT mice was higher than 50% in relation to TH-HZ), WT<50%, TH-HZ<50% and TH-HZ>50%. Peritoneal leukocytes were collected and phagocytosis, chemotaxis and proliferation of lymphocytes in the presence of lipopolysaccharide were analyzed. Glutathione reductase and glutathione peroxidase activities as well as oxidized/reduced glutathione ratio were studied. Results. TH-HZ>50% mice showed a deteriorated function and redox state in leukocytes respect to WT>50% and similar to old mice. However, TH-HZ<50% animals had similar values to those found in WT<50% mice. Conclusion. The haploinsufficiency of TH generates premature immunosenescence, which appears to be compensated by living together with an appropriate number of WT animals (AU)

Peripheral Lipopolysaccharide Challenge Induces Long-Term Changes in Tyrosine Hydroxylase Regulation in the Adrenal Medulla.

Immune activation can alter the activity of adrenal chromaffin cells. The effect of immune activation by lipopolysaccharide (LPS) on the regulation of tyrosine hydroxylase (TH) in the adrenal medulla in vivo was determined between 1 day and 6 months after LPS injection. The plasma levels of eleven cytokines were reduced 1 day after LPS injection, whereas the level for interleukin-10 was increased. The levels of all cytokines remained at control levels until 6 months when the levels of interleukin-6 and -4 were increased. One day after LPS injection, there was a decrease in TH-specific activity that may be due to decreased phosphorylation of serine 31 and 40. This decreased phosphorylation of serine 31 and 40 may be due to an increased activation of the protein phosphatase PP2A. One week after LPS injection, there was increased TH protein and increased phosphorylation of serine 40 that this was not accompanied by an increase in TH-specific activity. All TH parameters measured returned to basal levels between 1 month and 3 months. Six months after injection there was an increase in TH protein. This was associated with increased levels of the extracellular regulated kinase isoforms 1 and 2. This work shows that a single inflammatory event has the capacity to generate both short-term and long-term changes in TH regulation in the adrenal medulla of the adult animal. J. Cell. Biochem. 118: 2096-2107, 2017. © 2016 Wiley Periodicals, Inc.

Dopamine- and Tyrosine Hydroxylase-Immunoreactive Neurons in the Brain of the American Cockroach, Periplaneta americana.

The catecholamine dopamine plays several vital roles in the central nervous system of many species, but its neural mechanisms remain elusive. Detailed neuroanatomical characterization of dopamine neurons is a prerequisite for elucidating dopamine's actions in the brain. In the present study, we investigated the distribution of dopaminergic neurons in the brain of the American cockroach, Periplaneta americana, using two antisera: 1) an antiserum against dopamine, and 2) an antiserum against tyrosine hydroxylase (TH, an enzyme required for dopamine synthesis), and identified about 250 putatively dopaminergic neurons. The patterns of dopamine- and TH-immunoreactive neurons were strikingly similar, suggesting that both antisera recognize the same sets of "dopaminergic" neurons. The dopamine and TH antibodies intensively or moderately immunolabeled prominent brain neuropils, e.g. the mushroom body (memory center), antennal lobe (first-order olfactory center) and central complex (motor coordination center). All subdivisions of the mushroom body exhibit both dopamine and TH immunoreactivity. Comparison of immunolabeled neurons with those filled by dye injection revealed that a group of immunolabeled neurons with cell bodies near the calyx projects into a distal region of the vertical lobe, which is a plausible site for olfactory memory formation in insects. In the antennal lobe, ordinary glomeruli as well as macroglomeruli exhibit both dopamine and TH immunoreactivity. It is noteworthy that the dopamine antiserum labeled tiny granular structures inside the glomeruli whereas the TH antiserum labeled processes in the marginal regions of the glomeruli, suggesting a different origin. In the central complex, all subdivisions excluding part of the noduli and protocerebral bridge exhibit both dopamine and TH immunoreactivity. These anatomical findings will accelerate our understanding of dopaminergic systems, specifically in neural circuits underlying aversive memory formation and arousal, in insects.

Tyrosine hydroxylase immunoreactivity is common in the enteric nervous system in teleosts.

Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of catecholamines and TH immunoreactivity is indicative of cells synthesising either adrenaline/noradrenaline or dopamine. In this study, the distribution of TH immunoreactivity was examined in two distantly related teleost species, zebrafish (Danio rerio) and shorthorn sculpin (Myoxocephalus scorpius). In both species, TH-immunoreactive nerve cell bodies and varicose nerve fibres were common in the myenteric plexus of the intestine. However, no TH-immunoreactive nerve cell bodies were seen in the sculpin stomach. The TH-immunoreactive nerve cell bodies seemed to constitute a larger proportion of the total enteric population in shorthorn sculpin (50 ± 5 %, n = 3067 cells) compared with zebrafish (14 ± 2 %, n = 10,163 cells). In contrast, in sculpin, the TH-immunoreactive cells were smaller than the average enteric nerve cell bodies, whereas in zebrafish, the relationship was the opposite. In developing zebrafish larvae, TH-immunoreactive nerve cell bodies were common (approx. 75 % of the total population) at 3 days post-fertilization (dpf), but decreased in numbers between 3 and 7 dpf. In conclusion, in contrast to previous studies, TH-immunoreactive intrinsic neurons are common in the fish gut. Their role and function need to be further characterized in order to understand the potential importance of this enteric subpopulation in controlling various gut functions.

Transcription factor Nr4a1 couples sympathetic and inflammatory cues in CNS-recruited macrophages to limit neuroinflammation.

The molecular mechanisms that link the sympathetic stress response and inflammation remain obscure. Here we found that the transcription factor Nr4a1 regulated the production of norepinephrine (NE) in macrophages and thereby limited experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Lack of Nr4a1 in myeloid cells led to enhanced NE production, accelerated infiltration of leukocytes into the central nervous system (CNS) and disease exacerbation in vivo. In contrast, myeloid-specific deletion of tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine biosynthesis, protected mice against EAE. Furthermore, we found that Nr4a1 repressed autocrine NE production in macrophages by recruiting the corepressor CoREST to the Th promoter. Our data reveal a new role for macrophages in neuroinflammation and identify Nr4a1 as a key regulator of catecholamine production by macrophages.

The expression of ß3-adrenoceptor and muscarinic type 3 receptor immuno-reactivity in the major pelvic ganglion of the rat.

Bladder afferent outflow, linked to sensation, plays a critical role in bladder pathology: abnormal outflow results in altered sensation, leading to increased voiding frequency, urge and often incontinence. ß3-adrenoceptor agonists have been suggested to be beneficial in treating these symptoms. However, the absence of a significant sympathetic innervation of the detrusor and only a modest relaxation of bladder muscle by ß3 agonists has questioned the therapeutic site of action of ß3 agonists in the bladder. The present study was done to explore the possibility that ß3-adrenoceptors might be located in the pelvic plexus. Using the rat, where the pelvic plexus is located primarily within a single ganglion, the major pelvic ganglion (MPG), immuno-histochemical approaches were used to identify structures expressing ß3-adrenoceptor immuno-reactivity (ß3AR-IR). The only structures found to express ß3AR-IR were small-diameter tyrosine hydroxylase and vesicular mono-amine transporter immuno-reactive (TH-IR and vmat-IR) neurones. These neurones, found in clusters or singly on the periphery of the ganglion, or dispersed in smaller clumps throughout the MPG, are similar to the small intensely fluorescent (SIF) cells described previously. Not all small cells expressed ß3AR-IR. A population of the small cells were also immuno-reactive to the type 3 muscarinic receptor (M3R-IR) and the P2X3 purinergic receptor (P2X3-IR). Clumps of small cells were associated with calcitonin gene-related peptide immuno-reactive (CGRP-IR) nerve fibres (putative sensory fibres) and a small number were contacted by putative cholinergic nerves expressing immuno-reactivity to vesicular acetylcholine transporter (vacht-IR). These observations are consistent with the idea that small cells are interneurons and one of the components making up complex neural circuits within the MPG. The precise physiological role of these neural elements in the MPG is unknown. However, as one therapeutic action of ß3-adrenoceptor agonists is to modulate sensation, it is possible that these neural circuits may be involved in the regulation of afferent outflow and sensation.