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Drug Metabolism and Disposition: the... Oct 2008Plasma and brain concentrations of the nicotinic acetylcholine receptor antagonist and blood-brain barrier choline transporter substrate,...
Plasma and brain concentrations of the nicotinic acetylcholine receptor antagonist and blood-brain barrier choline transporter substrate, N,N'-dodecane-1,12-diyl-bis-3-picolinium dibromide (bPiDDB), were analyzed by liquid beta-scintillation spectrometry after administration of [14CH3]bPiDDB to male Sprague-Dawley rats. Plasma concentrations of [14CH3]bPiDDB were determined at 10 time points over 3 h. Absolute plasma bioavailabilities (1, 3, and 5.6 mg/kg s.c.) were 80.3, 68.2, and 103.7%, respectively. bPiDDB (1, 3, and 5.6 mg/kg) gave Cmax values of 0.13, 0.33, and 0.43 microg/ml, respectively, Tmax values of 5.0, 6.7, and 8.8 min, respectively, and t1/2 values of 76.0, 54.6, and 41.7 min, respectively. Mean area under the plasma concentration versus time curve from time zero to infinity (micrograms per minute per milliliter) and mean Cmax (microg/ml) values were dose-dependent (r2=0.9361 and 0.7968, respectively) over the dose range studied. No metabolism of [14CH3]bPiDDB was detected with any dose of bPiDDB administered. Only moderate protein binding (63-65% in plasma and 59-62% in brain supernatant) was observed, which was reversible. Brain concentrations and brain/plasma ratios of bPiDDB after a single 5.6 mg/kg s.c. dose over 5 to 60 min ranged from 0.09 to 0.33 microg/g brain tissue and were maximal at 10 min after injection, representing approximately 0.6% of the administered dose. Brain/blood ratio (0.18 at 5 min to 0.51 at 60 min after injection) was observed, indicating that clearance from brain is slower than clearance from plasma. The results show that bPiDDB is distributed rapidly from the site of injection into plasma, affords good plasma concentrations, and appears to reach brain tissues via facilitated transport by the blood-brain barrier choline transporter to afford therapeutically relevant concentrations in rat brain.
Topics: Animals; Area Under Curve; Brain; Chromatography, High Pressure Liquid; Male; Nicotinic Antagonists; Picolines; Protein Binding; Rats; Rats, Sprague-Dawley; Spectrophotometry, Ultraviolet
PubMed: 18617603
DOI: 10.1124/dmd.108.020354 -
Journal of Immunology (Baltimore, Md. :... Feb 2011Exposure to naturally occurring hydrocarbon oils is associated with the development of chronic inflammation and a wide spectrum of pathological findings in humans and...
Exposure to naturally occurring hydrocarbon oils is associated with the development of chronic inflammation and a wide spectrum of pathological findings in humans and animal models. The mechanism underlying the unremitting inflammatory response to hydrocarbons remains largely unclear. The medium-length alkane 2,6,10,14 tetramethylpentadecane (also known as pristane) is a hydrocarbon that potently elicits chronic peritonitis characterized by persistent infiltration of neutrophils and monocytes. In this study, we reveal the essential role of IL-1α in sustaining the chronic recruitment of neutrophils following 2,6,10,14 tetramethylpentadecane treatment. IL-1α and IL-1R signaling promote the migration of neutrophils to the peritoneal cavity in a CXCR2-dependent manner. This mechanism is at least partially dependent on the production of the neutrophil chemoattractant CXCL5. Moreover, although chronic infiltration of inflammatory monocytes is dependent on a different pathway requiring TLR-7, type I IFN receptor, and CCR2, the adaptor molecules MyD88, IL-1R-associated kinase (IRAK)-4, IRAK-1, and IRAK-2 are shared in regulating the recruitment of both monocytes and neutrophils. Taken together, our findings uncover an IL-1α-dependent mechanism of neutrophil recruitment in hydrocarbon-induced peritonitis and illustrate the interactions of innate immune pathways in chronic inflammation.
Topics: Animals; Chronic Disease; Hydrocarbons; Inflammation; Inflammation Mediators; Interleukin-1alpha; Mice; Mice, 129 Strain; Mice, Inbred BALB C; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Knockout; NIH 3T3 Cells; Neutrophil Infiltration; Oils; Picolines; Receptors, Interleukin-1; Signal Transduction
PubMed: 21191074
DOI: 10.4049/jimmunol.1001328 -
The American Journal of Clinical... Aug 2014Vitamin B-6 comprises a group of 6 interrelated vitamers and is essential for numerous physiologic processes, including brain functioning. Genetic disorders disrupting...
BACKGROUND
Vitamin B-6 comprises a group of 6 interrelated vitamers and is essential for numerous physiologic processes, including brain functioning. Genetic disorders disrupting vitamin B-6 metabolism have severe clinical consequences.
OBJECTIVE
To adequately diagnose known and novel disorders in vitamin B-6 metabolism, a reference set is required containing information on all vitamin B-6 vitamers in plasma and cerebrospinal fluid (CSF).
DESIGN
Concentrations of vitamin B-6 vitamers in the plasma and CSF of 533 adult subjects were measured by ultra high-performance liquid chromatography-tandem mass spectrometry.
RESULTS
The relative vitamin B-6 vitamer composition of plasma [pyridoxal phosphate (PLP) > pyridoxic acid (PA) > pyridoxal] differed from that of CSF (pyridoxal > PLP > PA > pyridoxamine). Sex influenced vitamin B-6 vitamer concentrations in plasma and CSF and should therefore be taken into account when interpreting vitamin B-6 vitamer concentrations. The strict ratios and strong correlations between vitamin B-6 vitamers point to a tight regulation of vitamin B-6 vitamer concentrations in blood and CSF. Given the unique design of this study, with simultaneously withdrawn blood and CSF from a large number of subjects, reliable CSF:plasma ratios and correlations of vitamin B-6 vitamers could be established.
CONCLUSIONS
We provide an extensive reference set of vitamin B-6 vitamer concentrations in plasma and CSF. In addition to providing insight on the regulation of individual vitamers and their intercompartmental distribution, we anticipate that these data will prove to be a valuable reference set for the diagnosis and treatment of conditions associated with altered vitamin B-6 metabolism.
Topics: Adolescent; Adult; Algorithms; Chromatography, High Pressure Liquid; Female; Humans; Limit of Detection; Male; Middle Aged; Netherlands; Pyridoxal; Pyridoxal Phosphate; Pyridoxamine; Pyridoxic Acid; Reference Values; Reproducibility of Results; Sex Characteristics; Tandem Mass Spectrometry; Vitamin B 6; Young Adult
PubMed: 24808484
DOI: 10.3945/ajcn.113.082008 -
Indian Journal of Pharmacology 2018In our preliminary study, chromium malate could decrease the blood glucose level in mice with diabetes and exhibits good benefits in treating glycometabolism and adipose...
OBJECTIVES
In our preliminary study, chromium malate could decrease the blood glucose level in mice with diabetes and exhibits good benefits in treating glycometabolism and adipose metabolization obstacle in rats with type 2 diabetes. This study was aimed at assessing the pharmacokinetics and bioavailability of chromium malate and influence on trace metals absorption in rats.
METHODS
BAPP 2.3 pharmacokinetic calculating program (China Pharmaceutical University Medicine Center) was used to calculate the pharmacokinetic parameters. Models of type 2 diabetic mellitus rats were applied to analyzed Ca, Mg, Fe, Cu, and Zn contents.
RESULTS
The results showed that mean retention time (MRT) in chromium malate group was significantly prolonged and the area under the curve (AUC) and relative bioavailability of chromium malate (male) group were significant increase compared to chromium picolinate group. The serum Ca, Mg, Fe, Cu, and Zn contents in chromium malate (at doses of 15 and 20 μg Cr/kg bw) groups were significantly increased compared to control group, chromium trichloride group, and chromium picolinate group in type 2 diabetes mellitus rats.
CONCLUSIONS
Those results indicated that chromium malate can significantly prolong MRT and increase AUC (male). Moreover, chromium malate is more effective at treating increased serum Ca, Mg, Fe, Cu, and Zn contents compared to chromium trichloride and chromium picolinate.
Topics: Administration, Intravenous; Administration, Oral; Animals; Biological Availability; Chlorides; Chromium Compounds; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Feces; Female; Malates; Male; Metals; Picolinic Acids; Rats; Rats, Sprague-Dawley; Tissue Distribution
PubMed: 30100655
DOI: 10.4103/ijp.IJP_505_17 -
Protein Science : a Publication of the... Jan 2016The importance of protonation states and proton transfer in pyridoxal 5'-phosphate (PLP)-chemistry can hardly be overstated. Although experimental approaches to...
The importance of protonation states and proton transfer in pyridoxal 5'-phosphate (PLP)-chemistry can hardly be overstated. Although experimental approaches to investigate pKa values can provide general guidance for assigning proton locations, only static pictures of the chemical species are available. To obtain the overall protein dynamics for the interpretation of detailed enzyme catalysis in this study, guided by information from solid-state NMR, we performed molecular dynamics (MD) simulations for the PLP-dependent enzyme tryptophan synthase (TRPS), whose catalytic mechanism features multiple quasi-stable intermediates. The primary objective of this work is to elucidate how the position of a single proton on the reacting substrate affects local and global protein dynamics during the catalytic cycle. In general, proteins create a chemical environment and an ensemble of conformational motions to recognize different substrates with different protonations. The study of these interactions in TRPS shows that functional groups on the reacting substrate, such as the phosphoryl group, pyridine nitrogen, phenolic oxygen and carboxyl group, of each PLP-bound intermediate play a crucial role in constructing an appropriate molecular interface with TRPS. In particular, the protonation states of the ionizable groups on the PLP cofactor may enhance or weaken the attractions between the enzyme and substrate. In addition, remodulation of the charge distribution for the intermediates may help generate a suitable environment for chemical reactions. The results of our study enhance knowledge of protonation states for several PLP intermediates and help to elucidate their effects on protein dynamics in the function of TRPS and other PLP-dependent enzymes.
Topics: Biocatalysis; Crystallography, X-Ray; Molecular Dynamics Simulation; Molecular Structure; Protons; Pyridoxal Phosphate; Tryptophan Synthase
PubMed: 26013176
DOI: 10.1002/pro.2709 -
International Journal of Molecular... May 2022Radical aminomutases are pyridoxal 5'-phosphate (PLP, a B vitamer)-dependent enzymes that require the generation of a 5'-deoxyadenosyl radical to initiate the catalytic...
Radical aminomutases are pyridoxal 5'-phosphate (PLP, a B vitamer)-dependent enzymes that require the generation of a 5'-deoxyadenosyl radical to initiate the catalytic cycle, to perform a 1,2 amino group shift reaction. The role of the nitrogen atom of PLP in radical aminomutases has not been investigated extensively yet. We report an alternative synthetic procedure to provide easy access to 1-deazaPLP (dAPLP), an isosteric analog of PLP which acts as a probe for studying the role of the nitrogen atom. Our results revealed that lysine 5,6-aminomutase (5,6-LAM), a radical aminomutase, reconstituted with dAPLP cannot turn over a substrate, demonstrating that the nitrogen atom is essential for radical aminomutases. In contrast, biochemical and spectroscopic studies on the S238A variant reconstituted with PLP revealed a minuscule loss of activity. This apparent anomaly can be explained by a water-mediated rescue of activity in S238A, as if mimicking the active site of lysine 2,3-aminomutase. This study leads to a better comprehension of how enzymes harness the optimum capability of PLP to realize catalysis.
Topics: Catalysis; Intramolecular Transferases; Lysine; Nitrogen; Pyridoxal Phosphate; Pyridoxine; Vitamin B 6; Vitamins
PubMed: 35563602
DOI: 10.3390/ijms23095210 -
Journal of Nutritional Science and... 2012To examine the responses of the levels of B₆-vitamers in several tissues to the dietary level of pyridoxine (PN), mice were fed diets containing 0, 1, 7 (the... (Comparative Study)
Comparative Study
To examine the responses of the levels of B₆-vitamers in several tissues to the dietary level of pyridoxine (PN), mice were fed diets containing 0, 1, 7 (the recommended level) or 35 mg PN HCl/kg diet for 5 wk. Compared with the 0 mg PN HCl/kg diet, the 35 mg PN HCl/kg diet caused the highest elevation in the concentration of pyridoxal 5'-phosphate (PLP) in small intestine and epididymal adipose tissue, moderate elevation in colon, lung, spleen and stomach, slight elevation in brain, kidney and liver (p<0.05), and no elevation in heart and gastrocnemius muscle. In general, the alterations in PLP level in many tissues and serum were remarkable for diets between 1 mg and 7 mg PN HCl/kg diets. Compared to the 7 mg PN HCl/kg diet, the 35 mg PN HCl/kg diet further elevated the PLP level in adipose tissue, spleen and stomach (p<0.05). Dietary supplemental PN elevated the level of PN in small intestine and colon in a dose-dependent manner (p<0.05), but not in other tissues. There was a significant correlation between the PN and PLP levels in small intestine and colon (p<0.05), implying that PN absorbed from the diet can be at least in part metabolized to PLP within the absorptive intestinal cells. The results suggest that the responses of concentrations of B₆-vitamers to dietary level of PN greatly differ among several tissues.
Topics: Animals; Brain; Diet; Dietary Supplements; Kidney; Liver; Male; Mice; Mice, Inbred ICR; Pyridoxal; Pyridoxal Phosphate; Pyridoxamine; Pyridoxine; Spleen
PubMed: 23419405
DOI: 10.3177/jnsv.58.446 -
Alcohol (Fayetteville, N.Y.) Jun 2017Nicotinic acetylcholine receptors (nAChRs) in the mesolimbic dopamine system have been implicated in ethanol behaviors. In particular, work in genetically engineered...
Nicotinic acetylcholine receptors (nAChRs) in the mesolimbic dopamine system have been implicated in ethanol behaviors. In particular, work in genetically engineered mice has demonstrated that α6-containing nAChRs are involved in ethanol consumption and sedation. A limitation of these studies is that the alteration in the receptor was present throughout development. The recently described α6β2 antagonist, N,N-decane-1,10-diyl-bis-3-picolinium diiodide (bPiDI), now makes it possible to test for the involvement of these receptors using a pharmacological approach. The aim of this study was to examine the role of α6β2 nAChRs in ethanol behaviors using a pharmacological approach. Adolescent C57BL/6J mice were treated with bPiDI 30 min prior to testing the mice for binge-like ethanol consumption in the drinking-in-the-dark (DID) test, ethanol-induced motor incoordination using the balance beam, and ethanol-induced sedation using the Loss of Righting Reflex (LORR) paradigm. Adolescent animals were chosen because they express a high amount of α6 mRNA relative to adult animals. Control studies were also performed to determine the effect of bPiDI on locomotor activity and ethanol metabolism. Female mice treated with 20 mg/kg bPiDI had reduced locomotor activity compared to saline-treated animals during the first 30 min following an acute injection. Pretreatment with the α6β2 antagonist reduced adolescent ethanol consumption but also reduced saccharin consumption. No significant effects were observed on ethanol-induced ataxia, sedation, or metabolism. This study provides evidence that α6β2 nAChRs are involved in locomotor activity as well as ethanol and saccharin consumption in adolescent animals.
Topics: Alcohol Drinking; Animals; Binge Drinking; Ethanol; Female; Locomotion; Male; Mice; Mice, Inbred C57BL; Nicotinic Antagonists; Picolines; Pyridinium Compounds; Receptors, Nicotinic; Saccharin
PubMed: 28457669
DOI: 10.1016/j.alcohol.2017.02.178 -
Poultry Science Apr 2021Three isotopic tracers ([2,3,3-H]-L-serine, [H]-L-betaine, and [1-C]-L-methionine) were administered by amnion injection into 18-day-old chick embryos to investigate the...
Three isotopic tracers ([2,3,3-H]-L-serine, [H]-L-betaine, and [1-C]-L-methionine) were administered by amnion injection into 18-day-old chick embryos to investigate the kinetics of methionine metabolism. The embryos utilized were from eggs collected from 34-week-old Cobb 500 broiler breeders that were fed either a control diet containing folic acid (1.25 mg/kg diet) and pyridoxine HCl (5 mg/kg diet) or diets devoid of supplemental pyridoxine or folic acid. Intermediate metabolites of methionine metabolism and polyamines were analyzed in 18-day-old chick embryos. There were no differences in hepatic [H] methionine or [H] cysteine enrichments or in physiological concentrations of sulfur amino acids for chick embryos from breeders fed the control diet and embryos from breeders fed diets containing no pyridoxine or folic acid. Supplementation of B or folic acid did not affect the production of methionine and cysteine in chick embryos. However, breeders fed the control diet with both folic acid and pyridoxine supplementation produced embryos with a two-fold reduction of hepatic homocysteine and increased spermine compared with embryos from breeders fed diets containing no supplemental pyridoxine or folic acid (P < 0.05). Hepatic S-adenosylmethionine for embryos from breeders fed no supplemental B was half the concentration compared with embryos from breeders fed the control diet. Embryos from breeders fed the control diet were utilized to determine the proportion of homocysteine going through remethylation and transsulfuration and also to determine the pathway of remethylation. Sixty-five percent of the methyl groups used for homocysteine remethylation from control embryos was via the MFMT pathway. Alternatively, 61% of homocysteine from control embryos was remethylated via the MFMT and the BHMT reactions and 39% of homocysteine was catabolized to cysteine via the transsulfuration pathway. These data show that in embryos, intermediate metabolites of methionine and polyamines increase in concentration when pyridoxine levels are provided in deficient concentrations to the breeder hen. In addition, this research demonstrates that folic acid deficient embryos conserve methionine, rather than catabolize it to cysteine.
Topics: Animals; Chick Embryo; Chickens; Diet; Female; Folic Acid; Methionine; Ovum; Pyridoxine; Vitamin B 6; Vitamins
PubMed: 33610900
DOI: 10.1016/j.psj.2020.12.075 -
Brain & Development May 2020The initial presentation of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is indistinguishable from that of complex febrile seizures...
BACKGROUND
The initial presentation of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is indistinguishable from that of complex febrile seizures (FS), which poses a great diagnostic challenge for clinicians. Excitotoxicity is speculated to be the pathogenesis of AESD. Vitamin B6 (VB6) is essential for the biosynthesis of gamma-aminobutyric acid, an inhibitory neurotransmitter. The aim of this study is to investigate our hypothesis that VB6 deficiency in the brain may play a role in AESD.
METHODS
We obtained cerebrospinal fluid (CSF) samples from pediatric patients with AESD after early seizures and those with FS. We measured pyridoxal 5'-phosphate (PLP) and pyridoxal (PL) concentrations in the CSF samples using high-performance liquid chromatography with fluorescence detection.
RESULTS
The subjects were 5 patients with AESD and 17 patients with FS. Age did not differ significantly between AESD and FS. In AESD, CSF PLP concentration was marginally lower (p = 0.0999) and the PLP-to-PL ratio was significantly (p = 0.0417) reduced compared to those in FS.
CONCLUSIONS
Although it is impossible to conclude that low PLP concentration and PLP-to-PL ratio are causative of AESD, this may be a risk factor for developing AESD. When combined with other markers, this finding may be useful in distinguishing AESD from FS upon initial presentation.
Topics: Brain Diseases; Child, Preschool; Female; Humans; Infant; Male; Pyridoxal; Pyridoxal Phosphate; Seizures; Vitamin B 6
PubMed: 32107100
DOI: 10.1016/j.braindev.2020.02.002