scholarly journals Cytochrome P450 2D Catalyze Steroid 21-Hydroxylation in the Brain

Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 699-705 ◽  
Author(s):  
Wataru Kishimoto ◽  
Toyoko Hiroi ◽  
Masakazu Shiraishi ◽  
Mayuko Osada ◽  
Susumu Imaoka ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Rat Brain ◽  
Aminobutyric Acid ◽  
Specific Chemical ◽  
Protein Levels ◽  
Receptor Modulator ◽  
Ic50 Value ◽  
Brain Microsomes ◽  
The Brain ◽  
Hydroxylation Activity

Abstract mRNA of cytochrome P450 21-hydroxylase (P450c21) is expressed in the brain, but little is known about the enzymatic properties of P450c21 in the brain. In the present study, we showed, by using various recombinant cytochrome P450 (CYP)2D enzymes and anti-CYP2D4- or P450c21-specific antibodies, that rat brain microsomal steroid 21-hydroxylation is catalyzed not by P450c21, but by CYP2D isoforms. Rat CYP2D4 and human CYP2D6, which are the predominant CYP2D isoforms in the brain, possess 21-hydroxylation activity for both progesterone and 17α-hydroxyprogesterone. In rat brain microsomes, these activities were not inhibited by anti-P450c21 antibodies, but they were effectively inhibited by the CYP2D-specific chemical inhibitor quinidine and by anti-CYP2D4 antibodies. mRNA and protein of CYP2D4 were expressed throughout the brain, especially in cerebellum, striatum, pons, and medulla oblongata, whereas the mRNA and protein levels of P450c21 were extremely low or undetectable. These results support the idea that CYP2D4, not P450c21, works as steroid 21-hydroxylase in the brain. Allopregnanolone, a representative γ-aminobutyric acid receptor modulator, was also hydroxylated at the C-21 position by recombinant CYP2D4 and CYP2D6. Rat brain microsomal allopregnanolone 21-hydroxylation was inhibited by fluoxetine with an IC50 value of 2 μm, suggesting the possibility that the brain CYP2D isoforms regulate levels of neurosteroids such as allopregnanolone, and that this regulation is modified by central nervous system-active drugs such as fluoxetine.

Immunochemical and Biochemical Evidence for Expression of Phenobarbital-and 3-Methylcholanthrene-Inducible Isoenzymes of Cytochrome P450 in Rat Brain

1998 ◽  
Vol 17 (6) ◽  
pp. 619-630 ◽  
Author(s):  
Devendra Parmar ◽  
Alok Dhawan ◽  
Monika Dayal ◽  
Prahlad K. Seth
Keyword(s):  
Cytochrome P450 ◽  
Rat Brain ◽  
Western Blotting ◽  
Polyclonal Antibodies ◽  
Biochemical Evidence ◽  
Catalytic Activities ◽  
Brain Microsomes ◽  
The Brain

Expression of P450 1A1l 1A2 and 2 B1l 2B2 isoenzymes in rat brain was studied by Western blotting, using polyclonal antibodies raised against hepatic P450 1A1l 1A2 and 2B1l 2B2 isoenzymes. In addition, biochemical characterizations of the catalytic activities, pen toxyresorufin O-dealkylation (PROD) and ethoxyre-sorufin O-deethylation (EROD), selective for P450 2B1l 2B2 (PROD) and P450 1A1l 1A2 (EROD), were performed with rat brain microsomes. Control rat brain microsomes did not crossreact with either of the antibodies, whereas microsomes obtained from 3-methylcholanthrene (MC)-pretreated rats revealed significant immunoreactivity with anti-P450 1A1l 1A2. Similar results were observed with phenobarbital (PB)-pretreated rats, with the brain microsomes exhibiting significant immunoreactivity with anti-P450 2B1l 2B2. The induction in the P450 isoenzymes after PB or MC pretreatment was much less in the brain in comparison to the liver. Enzymatic studies indicated that the activities of PROD and EROD were induced in brain 3—4 fold by PB and MC pretreatment, respectively, and were almost completely inhibited on in vitro addition of anti-P450 2B1l 2B2 and 1A1l 1A2. These data demonstrate the expression of P4501A1l 1A2 and 2B1l 2B2 isoenzymes in the brain and indicate that, as in liver, these isoenzymes catalyze EROD and PROD, respectively, in the rat brain.

Imidazo[1,2-B]Pyridazines. III. Syntheses and Central Nervous-System Activities of Some 6-Chloro-3-methoxy (and ethoxy)-2-aryl (and heteroaryl)imidazo[1,2-B]pyridazines

1988 ◽  
Vol 41 (8) ◽  
pp. 1149 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
MML Ngu
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Rat Brain ◽  
Active Compound ◽  
Plasma Membranes ◽  
Aminobutyric Acid ◽  
Ic50 Value ◽  
Standard Assay ◽  
Assay Conditions

The synthesis of a series of 6-chloro-3-methoxy(and ethoxy )-2- phenyl[and (variously substituted phenyl), thienyl, and naphthalenyl ] imidazo [1,2-b] pyridazines and a 6-fluoro analogue are reported. These compounds were tested for their ability to displace [3H]diazepam bound to washed rat brain plasma membranes. Under standard assay conditions (see Experimental) and in the presence of 100 μM γ- aminobutyric acid, 6-chloro-3-methoxy-2-(p-tolyl ) imidazo [1,2- b] pyridazine was the most active compound with an IC50 value of 148 nM (cf. diazepam, with IC50 of 4.2 nM).

Convulsions and the γ-aminobutyric acid content of rat brain

1968 ◽  
Vol 46 (5) ◽  
pp. 803-804 ◽  
Author(s):  
F. V. DeFeudis ◽  
K. A. C. Elliott
Keyword(s):  
High Pressure ◽  
Rat Brain ◽  
Acid Content ◽  
Aminobutyric Acid ◽  
The Brain

The observation of Wood and Watson that the γ-aminobutyric acid content of the brain decreases in animals that suffer convulsions during treatment with oxygen at high pressure has been confirmed. This decrease is prevented when seizures are prevented by prior intraperitoneal injections of hyperosmotic solutions. When seizures are induced by picrotoxin or pentylenetetrazol the GABA levels are slightly (and alanine levels considerably) increased.

scholarly journals β-Naphtoflavone and Ethanol Induce Cytochrome P450 and Protect towards MPP+ Toxicity in Human Neuroblastoma SH-SY5Y Cells

2018 ◽  
Vol 19 (11) ◽  
pp. 3369 ◽  
Author(s):  
Jesus Fernandez-Abascal ◽  
Mariantonia Ripullone ◽  
Aurora Valeri ◽  
Cosima Leone ◽  
Massimo Valoti
Keyword(s):  
Cytochrome P450 ◽  
Brain Metabolism ◽  
Brain Area ◽  
Human Neuroblastoma ◽  
In Vitro System ◽  
Protein Levels ◽  
The Brain ◽  
Cyp Isozymes

Cytochrome P450 (CYP) isozymes vary their expression depending on the brain area, the cell type, and the presence of drugs. Some isoforms are involved in detoxification and/or toxic activation of xenobiotics in central nervous system. However, their role in brain metabolism and neurodegeneration is still a subject of debate. We have studied the inducibility of CYP isozymes in human neuroblastoma SH-SY5Y cells, treated with β-naphtoflavone (β-NF) or ethanol (EtOH) as inducers, by qRT-PCR, Western blot (WB), and metabolic activity assays. Immunohistochemistry was used to localize the isoforms in mitochondria and/or endoplasmic reticulum (ER). Tetrazolium (MTT) assay was performed to study the role of CYPs during methylphenyl pyridine (MPP+) exposure. EtOH increased mRNA and protein levels of CYP2D6 by 73% and 60% respectively. Both β-NF and EtOH increased CYP2E1 mRNA (4- and 1.4-fold, respectively) and protein levels (64% both). The 7-ethoxycoumarin O-deethylation and dextromethorphan O-demethylation was greater in treatment samples than in controls. Furthermore, both treatments increased by 22% and 18%, respectively, the cell viability in MPP+-treated cells. Finally, CYP2D6 localized at mitochondria and ER. These data indicate that CYP is inducible in SH-SY5Y cells and underline this in vitro system for studying the role of CYPs in neurodegeneration.

scholarly journals Changes In Liver and Brain Cytochrome P450 after Multiple Cocaine Administration, Alone and in Combination with Nifedipine

2007 ◽  
Vol 58 (3) ◽  
pp. 287-291 ◽  
Author(s):  
Vessela Vitcheva ◽  
Mitka Mitcheva
Keyword(s):  
Cytochrome P450 ◽  
Calcium Channel ◽  
Calcium Channel Blocker ◽  
Wistar Rats ◽  
Channel Blocker ◽  
Cocaine Administration ◽  
Multiple Administration ◽  
Brain Microsomes ◽  
Male Wistar Rats ◽  
The Brain

Changes In Liver and Brain Cytochrome P450 after Multiple Cocaine Administration, Alone and in Combination with NifedipineThe objective of this study was to evaluate possible changes caused by multiple cocaine administration, alone and in combination with 1,4-dihydropiridine calcium channel blocker nifedipine, on cytochrome P450 levels both in the brain and liver. The experiment was done on male Wistar rats divided in four groups: control, treated with nifedipine (5 mg kg-1 i.p. for five days), treated with cocaine (15 mg kg-1 i.p. for five days), and treated with nifedipine and 30 minutes later with cocaine (also for five days). Total cytochrome P450 was measured spectrometrically in liver and brain microsomes. Multiple administration of cocaine alone and in combination with nifedipine did not change the brain P450 significantly. In the liver, nifedipine significantly increased P450 by 28 % vs. control. In contrast, cocaine significantly decreased P450 by 17 % vs. control. In animals treated with nifedipine and cocaine, cytochrome P450 increased 11 % (p<0.01) vs. control, decreased 12.5 % (p<0.001) vs. nifedipine group and increased 34 % (p<0.0001) vs. cocaine group. These results suggest that the cocaine and nifedipine interact at the metabolic level.

The Effect of Aspartame on Rat Brain Xenobiotic-Metabolizing Enzymes

2006 ◽  
Vol 25 (8) ◽  
pp. 453-459 ◽  
Author(s):  
A Vences-Mejía ◽  
N Labra-Ruíz ◽  
N Hernández-Martínez ◽  
V Dorado-González ◽  
J Gómez-Garduño ◽  
...  
Keyword(s):  
Body Weight ◽  
Cytochrome P450 ◽  
Rat Brain ◽  
Wistar Rats ◽  
Specific Response ◽  
Cytochrome P450 Enzymes ◽  
Metabolizing Enzymes ◽  
Protein Levels ◽  
Cyp 2E1 ◽  
Hepatic Microsomes

This study demonstrates that chronic aspartame (ASP) consumption leads to an increase of phase I metabolizing enzymes (cytochrome P450 (CYP)) in rat brain. Wistar rats were treated by gavage with ASP at daily doses of 75 and 125 mg/kg body weight for 30 days. Cerebrum and cerebellum were used to obtain microsomal fractions to analyse activity and protein levels of seven cytochrome P450 enzymes. Increases in activity were consistently found with the 75 mg/kg dose both in cerebrum and cerebellum for all seven enzymes, although not at the same levels: CYP 2E1-associated 4-nitrophenol hydroxylase (4-NPH) activity was increased 1.5-fold in cerebrum and 25-fold in cerebellum; likewise, CYP2B1-associated penthoxyresorufin O-dealkylase (PROD) activity increased 2.9- and 1.7-fold respectively, CYP2B2-associated benzyloxyresorufin O-dealkylase (BROD) 4.5- and 1.1- fold, CYP3A-associated erythromycin N-demethylase (END) 1.4- and 3.3-fold, CYP1A1-associated ethoxyresorufin O-deethylase (EROD) 5.5- and 2.8-fold, and CYP1A2- associated methoxyresorufin O-demethylase (MROD) 3.7- and 1.3-fold. Furthermore, the pattern of induction of CYP immunoreactive proteins by ASP paralleled that of 4-NHP-, PROD-, BROD-, END-, EROD- and MROD-related activities only in the cerebellum. Conversely, no differences in CYP concentration and activity were detected in hepatic microsomes of treated animals with respect to the controls, suggesting a brain-specific response to ASP treatment.

Distribution of epithelial sodium channels and mineralocorticoid receptors in cardiovascular regulatory centers in rat brain

2005 ◽  
Vol 289 (6) ◽  
pp. R1787-R1797 ◽  
Author(s):  
Md Shahrier Amin ◽  
Hong-Wei Wang ◽  
Erona Reza ◽  
Stewart C. Whitman ◽  
Balwant S. Tuana ◽  
...  
Keyword(s):  
Rat Brain ◽  
Sodium Channels ◽  
Experimental Models ◽  
Mineralocorticoid Receptors ◽  
Epithelial Sodium Channels ◽  
Functional Studies ◽  
Protein Levels ◽  
Neuronal Excitation ◽  
Salt Sensitive Hypertension ◽  
The Brain

Epithelial sodium channels (ENaC) are important for regulating sodium transport across epithelia. Functional studies indicate that neural mechanisms acting through mineralocorticoid receptors (MR) and sodium channels (presumably ENaC) are crucial to the development of sympathoexcitation and hypertension in experimental models of salt-sensitive hypertension. However, expression and localization of the ENaC in cardiovascular regulatory centers of the brain have not yet been studied. RT-PCR and immunohistochemistry were performed to study ENaC and MR expression at the mRNA and protein levels, respectively. Both mRNA and protein for α-, β-, and γ-ENaC subunits and MR were found to be expressed in the rat brain. All three ENaC subunits and MR were present in the supraoptic nucleus, magnocellular paraventricular nucleus, hippocampus, choroid plexus, ependyma, and brain blood vessels, suggesting the presence of multimeric channels and possible regulation by mineralocorticoids. In most cortical areas, thalamus, amygdala, and suprachiasmatic nucleus, notable expression of γ-ENaC was undetectable, whereas α- and β-ENaC were abundantly expressed pointing to the possibility of a heterogeneous population of channels. The findings suggest that stoichiometrically different populations of ENaC may be present in both epithelial and neural components in the brain, which may contribute to regulation of cerebrospinal fluid and interstitial Na+ concentration as well as neuronal excitation.

Liquid Chromatography Analysis of Clozapine in Rat Brain Tissue, Using its Molecularly Imprinted Polymer after Administration of Toxic Dose of Drug and Lipid Emulsion Therapy

2019 ◽  
Vol 15 (3) ◽  
pp. 251-257
Author(s):  
Bahareh Sadat Yousefsani ◽  
Seyed Ahmad Mohajeri ◽  
Mohammad Moshiri ◽  
Hossein Hosseinzadeh
Keyword(s):  
Rat Brain ◽  
Brain Tissue ◽  
Molecularly Imprinted Polymer ◽  
Lipid Emulsion ◽  
Limit Of Detection ◽  
Imprinted Polymer ◽  
Toxic Dose ◽  
Molecularly Imprinted ◽  
The Brain ◽  
Rat Brain Tissue

Background:Molecularly imprinted polymers (MIPs) are synthetic polymers that have a selective site for a given analyte, or a group of structurally related compounds, that make them ideal polymers to be used in separation processes.Objective:An optimized molecularly imprinted polymer was selected and applied for selective extraction and analysis of clozapine in rat brain tissue.Methods:A molecularly imprinted solid-phase extraction (MISPE) method was developed for preconcentration and cleanup of clozapine in rat brain samples before HPLC-UV analysis. The extraction and analytical process was calibrated in the range of 0.025-100 ppm. Clozapine recovery in this MISPE process was calculated between 99.40 and 102.96%. The limit of detection (LOD) and the limit of quantification (LOQ) of the assay were 0.003 and 0.025 ppm, respectively. Intra-day precision values for clozapine concentrations of 0.125 and 0.025 ppm were 5.30 and 3.55%, whereas inter-day precision values of these concentrations were 9.23 and 6.15%, respectively. In this study, the effect of lipid emulsion infusion in reducing the brain concentration of drug was also evaluated.Results:The data indicated that calibrated method was successfully applied for the analysis of clozapine in the real rat brain samples after administration of a toxic dose to animal. Finally, the efficacy of lipid emulsion therapy in reducing the brain tissue concentration of clozapine after toxic administration of drug was determined.Conclusion:The proposed MISPE method could be applied in the extraction and preconcentration before HPLC-UV analysis of clozapine in rat brain tissue.

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