1
|
Specker E, Wesolowski R, Schütz A, Matthes S, Mallow K, Wasinska-Kalwa M, Winkler L, Oder A, Alenina N, Pleimes D, von Kries JP, Heinemann U, Bader M, Nazaré M. Structure-Based Design of Xanthine-Imidazopyridines and -Imidazothiazoles as Highly Potent and In Vivo Efficacious Tryptophan Hydroxylase Inhibitors. J Med Chem 2023; 66:14866-14896. [PMID: 37905925 DOI: 10.1021/acs.jmedchem.3c01454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Tryptophan hydroxylases catalyze the first and rate-limiting step in the biosynthesis of serotonin, a well-known neurotransmitter that plays an important role in multiple physiological functions. A reduction of serotonin levels, especially in the brain, can cause dysregulation leading to depression or insomnia. In contrast, overproduction of peripheral serotonin is associated with symptoms like carcinoid syndrome and pulmonary arterial hypertension. Recently, we developed a class of TPH inhibitors based on xanthine-benzimidazoles, characterized by a tripartite-binding mode spanning the binding sites of the cosubstrate pterin and the substrate tryptophan and by chelation of the catalytic iron ion. Herein, we describe the structure-based development of a second generation of xanthine-imidiazopyridines and -imidazothiazoles designed to inhibit TPH1 in the periphery while preventing the interaction with TPH2 in the brain. Lead compound 32 (TPT-004) shows superior pharmacokinetic and pharmacodynamic properties as well as efficacy in preclinical models of peripheral serotonin attenuation and colorectal tumor growth.
Collapse
Affiliation(s)
- Edgar Specker
- Chemical Biology Platform, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
- Trypto Therapeutics GmbH, Robert-Rössle Straße 10, 13125 Berlin, Germany
| | - Radoslaw Wesolowski
- Trypto Therapeutics GmbH, Robert-Rössle Straße 10, 13125 Berlin, Germany
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Anja Schütz
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Susann Matthes
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Keven Mallow
- Chemical Biology Platform, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Malgorzata Wasinska-Kalwa
- Chemical Biology Platform, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Lars Winkler
- Experimental Pharmacology and Oncology GmbH, Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Andreas Oder
- Chemical Biology Platform, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Potsdamer Straße 58, 10785 Berlin, Germany
| | - Dirk Pleimes
- Trypto Therapeutics GmbH, Robert-Rössle Straße 10, 13125 Berlin, Germany
| | - Jens Peter von Kries
- Chemical Biology Platform, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Udo Heinemann
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Michael Bader
- Trypto Therapeutics GmbH, Robert-Rössle Straße 10, 13125 Berlin, Germany
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Potsdamer Straße 58, 10785 Berlin, Germany
- Charité─Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
- University of Lübeck, Institute for Biology, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Marc Nazaré
- Chemical Biology Platform, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| |
Collapse
|
2
|
Chen N, Zhao M, Guo Y, Wu N, Cao B, Zhan B, Zhou T, Li Y, Zhu F, Chen W, Li Y, Zhang L. D-mannose is a rapid inducer of ACSS2 to trigger rapid and long-lasting antidepressant responses through augmenting BDNF and TPH2 levels. Transl Psychiatry 2023; 13:338. [PMID: 37914710 PMCID: PMC10620401 DOI: 10.1038/s41398-023-02636-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 11/03/2023] Open
Abstract
The potentiation of synaptic plasticity and serotonin generation by brain-derived neurotrophic factor (BDNF) and tryptophan hydroxylase 2 (TPH2) is well characterized to facilitate rapid and long-lasting antidepressant actions. Therefore, the identification of the key protein that simultaneously controls both BDNF and TPH2 is important for the treatment of depression. We show here that a lack of acetyl-CoA synthetase short-chain family member 2 (ACSS2) causes impairments in BDNF-dependent synaptic plasticity and tryptophan hydroxylase 2 (TPH2)-mediated serotonin generation, thereby contributing to spontaneous and chronic restraint stress (CRS)-induced depressive-like behavior in mice. Conversely, D-mannose is identified as a rapid ACSS2 inducer and thus mediates rapid and long-lasting antidepressant-like effects. Mechanistically, acute and chronic D-mannose administration inhibits the phosphorylation of EF2 to increase BDNF levels and reverse the reduction of TPH2 histone acetylation and transcription. We reveal that ACSS2 promotes TPH2 histone acetylation and transcription with the requirement of AMPK activation. To elevate nuclear ACSS2 levels, D-mannose can rapidly and persistently activate AMPK via Ca2+-CAMKK2 and the lysosomal AXIN-LKB1 pathway to facilitate its fast-acting and persistent antidepressant responses. Taken together, the results presented here reveal that ACSS2 functions as a novel target to link rapid and persistent antidepressant actions and further suggest that D-mannose is a potential therapeutic agent to resist depression through its augmentation of the ACSS2 dependent BDNF and TPH2 pathways.
Collapse
Affiliation(s)
- Nuo Chen
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Ming Zhao
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yaxin Guo
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Nan Wu
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Baihui Cao
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Bing Zhan
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Tian Zhou
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yubin Li
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Faliang Zhu
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - WanJun Chen
- Mucosal Immunology Section, NIDCR, US National Institutes of Health, Bethesda, MD, USA.
| | - Yan Li
- Department of Pathogen Biology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China.
| | - Lining Zhang
- Department of Immunology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China.
| |
Collapse
|
3
|
Evsiukova VS, Arefieva AB, Sorokin IE, Kulikov AV. Age-Related Alterations in the Level and Metabolism of Serotonin in the Brain of Males and Females of Annual Turquoise Killifish ( Nothobranchius furzeri). Int J Mol Sci 2023; 24:ijms24043185. [PMID: 36834593 PMCID: PMC9959878 DOI: 10.3390/ijms24043185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/03/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
The annual turquoise killifish (Nothobranchius furzeri) is a laboratory model organism for neuroscience of aging. In the present study, we investigated for the first time the levels of serotonin and its main metabolite, 5-hydroxyindoleacetic acid, as well as the activities of the key enzymes of its synthesis, tryptophan hydroxylases, and degradation, monoamine oxidase, in the brains of 2-, 4- and 7-month-old male and female N. furzeri. The marked effect of age on the body mass and the level of serotonin, as well as the activities of tryptophan hydroxylases and monoamine oxidase in the brain of killifish were revealed. The level of serotonin decreased in the brain of 7-month-old males and females compared with 2-month-old ones. A significant decrease in the tryptophan hydroxylase activity and an increase in the monoamine oxidase activity in the brain of 7-month-old females compared to 2-month-old females was shown. These findings agree with the age-related alterations in expression of the genes encoding tryptophan hydroxylases and monoamine oxidase. N. furzeri is a suitable model with which to study the fundamental problems of age-related changes of the serotonin system in the brain.
Collapse
Affiliation(s)
- Valentina S. Evsiukova
- Department of Psychoneuropharmacology, Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Alla B. Arefieva
- Department of Genetic Collections of Neural Disorders, Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Ivan E. Sorokin
- Department of Monogenic Forms of Human Common Disorders, Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Alexander V. Kulikov
- Department of Genetic Collections of Neural Disorders, Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Correspondence: ; Tel.: +7-3833636187
| |
Collapse
|
4
|
Koumarianou A, Daskalakis K, Tsoli M, Kaltsas G, Pavel M. Efficacy, safety and unmet needs of evolving medical treatments for carcinoid syndrome. J Neuroendocrinol 2022; 34:e13174. [PMID: 35794780 DOI: 10.1111/jne.13174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/06/2022] [Accepted: 05/31/2022] [Indexed: 11/25/2022]
Abstract
This review reports on the currently available medical treatment options for the control of symptoms due to carcinoid syndrome in patients with neuroendocrine tumors. The efficacy and adverse events (AEs) of approved drugs such as somatostatin analogues (SSA), telotristat ethyl (TE) and interferon-alpha, are reviewed. Somatostatin analogues remain the standard treatment of carcinoid syndrome based on the high expression of somatostatin receptors and the resulting inhibition of secretion of bioactive compounds; their use is associated with relatively mild AEs, involving mainly the gastrointestinal system, and being usually transient. Although dose escalation of SSA remains an unapproved option, it is clinically implemented to alleviate symptoms in refractory carcinoid syndrome and supported by the most recent guidelines. The side effects associated with the increased dose are in general mild and consistent with standard dose of SSA. Telotristat ethyl, an oral inhibitor of tryptophan hydroxylase, the rate-limiting enzyme in serotonin biosynthesis, represents a rather novel innovative treatment option in patients with carcinoid syndrome suffering from diarrhea and complements the standard therapy of SSA. Given the low toxicity profile, TE may be considered an early add-on treatment to SSA in patients with uncontrolled carcinoid syndrome. However, further prolonged follow-up of patients treated with TE may be needed to exclude potential AEs, such as liver toxicity or depressed mood, in patients with long-term treatment. Interferon alpha is a cytokine with direct inhibitory effect on hormone secretion and tumor cell proliferation and an approved therapy in carcinoid syndrome but is associated with significant AEs in the majority of the patients requiring frequently dose reduction. The finding of a more favorable tolerability of pegylated interferon needs to be confirmed in a prospective study.
Collapse
Affiliation(s)
- Anna Koumarianou
- Hematology-Oncology Unit, Fourth Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Kosmas Daskalakis
- Department of Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- 2nd Department of Surgery, "Korgialenio-Benakio", Red Cross General Hospital, Athens, Greece
| | - Marina Tsoli
- 1st Propaedeutic Department of Internal Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Gregory Kaltsas
- 1st Propaedeutic Department of Internal Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Marianne Pavel
- Department of Endocrinology, Universitatsklinikum Erlangen, Erlangen, Germany
| |
Collapse
|
5
|
Zou YY, Wu XY, Shu L, Ji PL, Gong HS, Rong WF. [Perinatal antibiotics exposure causes increase in serum 5-hydroxytryptamine level as well as changes in behavior and gastrointestinal motility in the male offspring in mice]. Sheng Li Xue Bao 2020; 72:285-298. [PMID: 32572427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The current study was aimed to investigate the potential effects of perinatal exposure to therapeutic dose of penicillin and cefixime on the cognitive behaviors, gastrointestinal (GI) motility and serum 5-hydroxytryptamine (5-HT) level in the offspring. Pregnant rats were continuously treated with cefixime or penicillin in the period between 1 week before and 1 week after labor. Behavior tests, including social preference, self-grooming and elevated plus maze tests, and intestinal motility tests were carried out on the offspring at age of 4 to 10 weeks. Serum 5-HT levels were detected with ELISA, and potassium/sodium hyperpolarization activated cyclic nucleotide-gated channel 2 (HCN2) and tryptophan hydroxylase 1 (TPH1) expression levels in colon epithelium of offspring were detected by Western blot and RT-qPCR. The results showed that, compared with the naive group, cefixime increased social behavior in the female offspring, but did not affect the male offspring. Compared with the naive group, cefixime significantly decreased colonic and intestinal transits, and increased cecum net weight and standardized cecum net weight in the male offspring, but did not affect the female offspring. The serum 5-HT levels in the male offspring, rather than the female offspring, in cefixime and penicillin groups were significantly increased compared with that in the naive group. The protein expression level of HCN2 in colon epithelium of the offspring in cefixime group was significantly down-regulated, and the TPH1 expression level was not significantly changed, compared with that in the naive group. These results suggest that perinatal antibiotics exposure may affect neural development and GI functions of the offspring, and the mechanism may involve peripheral 5-HT and gender-dependent factor.
Collapse
Affiliation(s)
- Yu-Yao Zou
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiao-Yu Wu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lan Shu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Pei-Lin Ji
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Hua-Shan Gong
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wei-Fang Rong
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| |
Collapse
|
6
|
Ebenezer PJ, Wilson CB, Wilson LD, Nair AR, J F. The Anti-Inflammatory Effects of Blueberries in an Animal Model of Post-Traumatic Stress Disorder (PTSD). PLoS One 2016; 11:e0160923. [PMID: 27603014 PMCID: PMC5014311 DOI: 10.1371/journal.pone.0160923] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/27/2016] [Indexed: 12/21/2022] Open
Abstract
Post-traumatic stress disorder (PTSD) is a trauma and stressor-related disorder that results in a prolonged stress response. It is associated with increased oxidative stress and inflammation in the prefrontal cortex (PFC) and hippocampus (HC). The only approved therapy for PTSD is selective serotonin re-uptake inhibitors (SSRIs), but their efficacy is marginal. Recently, we demonstrated that over-production of norepinephrine (NE) as the possible reason for the lack of efficacy of SSRIs. Hence, there is a need for novel therapeutic approaches for the treatment of PTSD. In this study, we investigated the anti-inflammatory role of blueberries in modulating inflammatory markers and neurotransmitter levels in PTSD. Rats were fed either a blueberry enriched (2%) or a control diet. Rats were exposed to cats for one hour on days 1 and 11 of a 31-day schedule to simulate traumatic conditions. The rats were also subjected to psychosocial stress via daily cage cohort changes. At the end of the study, the rats were euthanized and the PFC and HC were isolated. Monoamines were measured by high-performance liquid chromatography. Reactive oxygen species (ROS), gene and protein expression levels of inflammatory cytokines were also measured. In our PTSD model, NE levels were increased and 5-HT levels were decreased when compared to control. In contrast, a blueberry enriched diet increased 5-HT without affecting NE levels. The rate limiting enzymes tyrosine hydroxylase and tryptophan hydroxylase were also studied and they confirmed our findings. The enhanced levels free radicals, gene and protein expression of inflammatory cytokines seen in the PTSD group were normalized with a blueberry enriched diet. Decreased anxiety in this group was shown by improved performance on the elevated plus-maze. These findings indicate blueberries can attenuate oxidative stress and inflammation and restore neurotransmitter imbalances in a rat model of PTSD.
Collapse
Affiliation(s)
- Philip J. Ebenezer
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, Louisiana, United States of America
| | - C. Brad Wilson
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, Louisiana, United States of America
| | - Leslie D. Wilson
- Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, Louisiana, United States of America
| | - Anand R. Nair
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, Louisiana, United States of America
| | - Francis J
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, Louisiana, United States of America
- * E-mail:
| |
Collapse
|
7
|
Abstract
The monoamine serotonin (5-HT) exerts key neuromodulatory activities in all animal phyla, but the development and function of the serotonergic system is still incompletely understood. The zebrafish Danio rerio is an excellent model to approach this question since it is amenable to a combination of genetic, molecular and embryological studies. In order to characterize the organization of serotonergic neurons in the zebrafish we cloned two cDNAs encoding distinct forms of tryptophan hydroxylase (Tph), the rate-limiting enzyme in serotonin synthesis. We report here the pattern of expression of these two genes in relation with immunoreactive TH and 5-HT nuclei in the developing zebrafish embryo and early larva. tphD1 expression starts at 22 h post-fertilization (hpf) in the epiphysis and in basal spinal cells. Expression persists in the epiphysis until at least 4 days (dpf). Between 48 hpf and 3 dpf, tphD1 expression is initiated in retinal amacrine cells and in restricted preoptic and posterior tubercular nuclei within the basal diencephalon. At 3 and 4 dpf, tphD1 expression is newly initiated in the caudal hypothalamus and in branchial arches-associated neurons. tphD2 mRNA is detected transiently (between 30 somites and 32 hpf) in a restricted preoptic nucleus. All sites of tphD1 or D2 expression within the anterior central nervous system are also immunoreactive for 5-HT, but are not positive for TH. However, neither tphD gene is expressed in raphe nuclei, suggesting that additional tph gene(s) exist in zebrafish to account for 5-HT synthesis in that location. The co-expression of tphD1, tphD2 and 5-HT in the zebrafish diencephalon appears in striking contrast to the situation in mammals, where diencephalic serotonin results from re-uptake rather than from local production.
Collapse
Affiliation(s)
- Gianfranco Bellipanni
- Zebrafish Neurogenetics Junior Research Group, Institute of Virology, Technical University-Munich, Trogerstrasse 4b, D-81675 Munich, Germany.
| | | | | |
Collapse
|
8
|
Thomas P, Rahman MS, Khan IA, Kummer JA. Widespread endocrine disruption and reproductive impairment in an estuarine fish population exposed to seasonal hypoxia. Proc Biol Sci 2007; 274:2693-701. [PMID: 17725976 PMCID: PMC2279220 DOI: 10.1098/rspb.2007.0921] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 08/06/2007] [Accepted: 08/07/2007] [Indexed: 11/12/2022] Open
Abstract
The long-term effects on marine fish populations of the recent increase worldwide in the incidence of coastal hypoxia are unknown. Here we show that chronic environmental exposure of Atlantic croaker (Micropogonias undulatus) to hypoxia in a Florida estuary caused marked suppression of ovarian and testicular growth which was accompanied by endocrine disruption. Laboratory hypoxia studies showed that the endocrine disruption was associated with impairment of reproductive neuroendocrine function and decreases in hypothalamic serotonin (5-HT) content and the activity of the 5-HT biosynthetic enzyme, tryptophan hydroxylase. Pharmacological restoration of hypothalamic 5-HT levels also restored neuroendocrine function, indicating that the stimulatory serotonergic neuroendocrine pathway is a major site of hypoxia-induced inhibition. Inhibition of tryptophan hydroxylase activity to downregulate reproductive activity could have evolved as an adaptive mechanism to survive periodic hypoxia, but in view of the recent increased incidence of coastal hypoxia could become maladaptive and potentially affect fish population abundance and threaten valuable fishery resources.
Collapse
Affiliation(s)
- Peter Thomas
- Marine Science Institute, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373, USA.
| | | | | | | |
Collapse
|
9
|
Abstract
A new selective amperometric biosensor for reagentless L-tryptophan determination has been developed using immobilized tryptophan-2-monooxygenase (TMO, EC 1.13.12.3). This enzyme-based biosensor provides a rapid-response detection system for concentrations of L-tryptophan between 25 and 1,000 microM in a batch mode system and between 100 and 50,000 microM in a flow-injection mode. The response time was 30 seconds, and the total analysis time was less than 3 minutes. The biosensor retained catalytic activity and fidelity of phenylalanine and tryptophan response for greater than 4 months with repeated usage. The biosensor selectivity to L-tryptophan was dramatically increased relative to phenylalanine when a competitive inhibitor of TMO, indole acetamide (IA), was included. The biosensor was successfully used for L-tryptophan determination in nutrition broth, giving values identical to those determined by HPLC analysis.
Collapse
Affiliation(s)
- A L Simonian
- Texas A&M University, Department of Biochemistry and Biophysics, College Station 77843-2128, USA.
| | | | | | | |
Collapse
|
10
|
Abstract
In the present study, the effects of long-term pinealectomy on tryptophan, 5-hydroxytryptamine (5-HT or serotonin), 5-hydroxy-3-indoleacetic acid (5-HIAA), and tryptophan hydroxylase and monoamine oxidase activities were studied in preoptic area-anterior hypothalamus (POA-AH) and in the medial and posterior hypothalamus of the rat. After pinealectomy, 5-HT levels decreased significantly in medial hypothalamus but increased in the POA-AH. The levels of 5-HIAA decreased significantly in the POA-AH and medial hypothalamus. Tryptophan levels remained unchanged while tryptophan hydroxylase activity diminished significantly in POA-AH and medial hypothalamus. Monoamine oxidase activity remained unchanged in the hypothalamic regions. These results suggest that pinealectomy induces differential inhibitory actions on the serotoninergic terminal regions, mainly in anterior and medial hypothalamic areas.
Collapse
Affiliation(s)
- J Míguez
- Departamento de Fisiología Animal, Facultad de Biología, Universidad de Santiago de Compostela, Galicia, Spain
| | | | | | | |
Collapse
|
11
|
Kuhn DM, Rosenberg RC, Lovenberg W. Determination of some molecular parameters of tryptophan hydroxylase from rat midbrain and murine mast cell. J Neurochem 1979; 33:15-21. [PMID: 458447 DOI: 10.1111/j.1471-4159.1979.tb11700.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
12
|
Osborne NN. Proceedings: Application of the dansyl procedure to study the metabolism and accumulation of 5-hydroxytryptamine in characterized neurones of Helix pomatia. Br J Pharmacol 1973; 49:170P-171P. [PMID: 4787544 PMCID: PMC1776446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
|
13
|
|
14
|
|
15
|
BURKARD WP, GEY KF, PLETSCHER A. [INHIBITION OF TRYPTOPHAN HYDROXYLASE BY ALPHA-METHYLDOPA]. Helv Physiol Pharmacol Acta 1964; 22:C7-9. [PMID: 14181561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
|