ABSTRACT
BACKGROUND: The capacity of a polyphenol-enriched diet to modulate the epigenome in vivo is partly unknown. Given the beneficial metabolic effects of a Mediterranean (MED) diet enriched in polyphenols and reduced in red/processed meat (green-MED), as previously been proven by the 18-month DIRECT PLUS randomized controlled trial, we analyzed the effects of the green-MED diet on methylome and transcriptome levels to highlight molecular mechanisms underlying the observed metabolic improvements. METHODS: Our study included 260 participants (baseline BMI = 31.2 kg/m2, age = 5 years) of the DIRECT PLUS trial, initially randomized to one of the intervention arms: A. healthy dietary guidelines (HDG), B. MED (440 mg polyphenols additionally provided by walnuts), C. green-MED (1240 mg polyphenols additionally provided by walnuts, green tea, and Mankai: green duckweed shake). Blood methylome and transcriptome of all study subjects were analyzed at baseline and after completing the 18-month intervention using Illumina EPIC and RNA sequencing technologies. RESULTS: A total of 1573 differentially methylated regions (DMRs; false discovery rate (FDR) < 5 %) were found in the green-MED compared to the MED (177) and HDG (377) diet participants. This corresponded to 1753 differentially expressed genes (DEGs; FDR < 5 %) in the green-MED intervention compared to MED (7) and HDG (738). Consistently, the highest number (6 %) of epigenetic modulating genes was transcriptionally changed in subjects participating in the green-MED intervention. Weighted cluster network analysis relating transcriptional and phenotype changes among participants subjected to the green-MED intervention identified candidate genes associated with serum-folic acid change (all P < 1 × 10-3) and highlighted one module including the KIR3DS1 locus, being negatively associated with the polyphenol changes (e.g. P < 1 × 10-4), but positively associated with the MRI-assessed superficial subcutaneous adipose area-, weight- and waist circumference- 18-month change (all P < 0.05). Among others, this module included the DMR gene Cystathionine Beta-Synthase, playing a major role in homocysteine reduction. CONCLUSIONS: The green-MED high polyphenol diet, rich in green tea and Mankai, renders a high capacity to regulate an individual's epigenome. Our findings suggest epigenetic key drivers such as folate and green diet marker to mediate this capacity and indicate a direct effect of dietary polyphenols on the onecarbon metabolism.
Subject(s)
Diet, Mediterranean , Humans , Polyphenols/pharmacology , Diet , Obesity , Tea , Epigenesis, GeneticABSTRACT
Songorine (SON) is a diterpenoid alkaloid from Aconitum plants. Preparations of Aconitum roots have been employed in traditional oriental herbal medicine, however, their mechanisms of action are still unclear. Since GABA-receptors are possible brain targets of SON, we investigated which subtypes of GABA-receptors contribute to the effects of SON, and how SON affects anxiety-like trait behavior and psychomotor cognitive performance of rats. First, we investigated the effects of microiontophoretically applied SON alone and combined with GABA-receptor agents picrotoxin and saclofen on neuronal firing activity in various brain areas. Next, putative anxiolytic effects of SON (1.0-3.0 mg/kg) were tested against the GABA-receptor positive allosteric modulator reference compound diazepam (1.0-5.0 mg/kg) in the elevated zero maze (EOM). Furthermore, basic cognitive effects were assessed in a rodent version of the psychomotor vigilance task (PVT). Local application of SON predominantly inhibited the firing activity of neurons. This inhibitory effect of SON was successfully blocked by GABA(A)-receptor antagonist picrotoxin but not by GABA(B)-receptor antagonist saclofen. Similar to GABA(A)-receptor positive allosteric modulator diazepam, SON increased the time spent by animals in the open quadrants of the EOM without any signs of adverse psychomotor and cognitive effects observed in the PVT. We showed that, under in vivo conditions, SON acts as a potent GABA(A)-receptor agonist and effectively decreases anxiety without observable side effects. The present findings facilitate the deeper understanding of the mechanism of action and the widespread pharmacological use of diterpene alkaloids in various CNS indications.
ABSTRACT
BACKGROUND: The effect of diet on age-related brain atrophy is largely unproven. OBJECTIVES: We aimed to explore the effect of a Mediterranean diet (MED) higher in polyphenols and lower in red/processed meat (Green-MED diet) on age-related brain atrophy. METHODS: This 18-mo clinical trial longitudinally measured brain structure volumes by MRI using hippocampal occupancy score (HOC) and lateral ventricle volume (LVV) expansion score as neurodegeneration markers. Abdominally obese/dyslipidemic participants were randomly assigned to follow 1) healthy dietary guidelines (HDG), 2) MED, or 3) Green-MED diet. All subjects received free gym memberships and physical activity guidance. Both MED groups consumed 28 g walnuts/d (+440 mg/d polyphenols). The Green-MED group consumed green tea (3-4 cups/d) and Mankai (Wolffia-globosa strain, 100 g frozen cubes/d) green shake (+800 mg/d polyphenols). RESULTS: Among 284 participants (88% men; mean age: 51 y; BMI: 31.2 kg/m2; APOE-ε4 genotype = 15.7%), 224 (79%) completed the trial with eligible whole-brain MRIs. The pallidum (-4.2%), third ventricle (+3.9%), and LVV (+2.2%) disclosed the largest volume changes. Compared with younger participants, atrophy was accelerated among those ≥50 y old (HOC change: -1.0% ± 1.4% compared with -0.06% ± 1.1%; 95% CI: 0.6%, 1.3%; P < 0.001; LVV change: 3.2% ± 4.5% compared with 1.3% ± 4.1%; 95% CI: -3.1%, -0.8%; P = 0.001). In subjects ≥ 50 y old, HOC decline and LVV expansion were attenuated in both MED groups, with the best outcomes among Green-MED diet participants, as compared with HDG (HOC: -0.8% ± 1.6% compared with -1.3% ± 1.4%; 95% CI: -1.5%, -0.02%; P = 0.042; LVV: 2.3% ± 4.7% compared with 4.3% ± 4.5%; 95% CI: 0.3%, 5.2%; P = 0.021). Similar patterns were observed among younger subjects. Improved insulin sensitivity over the trial was the parameter most strongly associated with brain atrophy attenuation (P < 0.05). Greater Mankai, green tea, and walnut intake and less red and processed meat were significantly and independently associated with reduced HOC decline (P < 0.05). Elevated urinary concentrations of the polyphenols urolithin-A (r = 0.24; P = 0.013) and tyrosol (r = 0.26; P = 0.007) were significantly associated with lower HOC decline. CONCLUSIONS: A Green-MED (high-polyphenol) diet, rich in Mankai, green tea, and walnuts and low in red/processed meat, is potentially neuroprotective for age-related brain atrophy.This trial was registered at clinicaltrials.gov as NCT03020186.
Subject(s)
Diet, Mediterranean , Juglans , Atrophy , Brain/diagnostic imaging , Exercise , Female , Humans , Male , Middle Aged , Polyphenols/pharmacology , TeaABSTRACT
According to research, almost every second oncology patient experiences intense distress during their oncology treatment. The development of new medical treatment options in cancer care allows longer survival for cancer patients. Because of this, quality of life becomes an increasingly important factor during treatments. Psycho-oncological interventions include all psychosocial interventions that are designed to positively influence the patient's psychosocial adaptation and adjustment to diagnosis, treatment, and survivorship. Interventions also promote rehabilitation progress and help the emotional integration of disease-related crisis and trauma. Psycho-oncological therapies are supposed to manage cancer-related distress and other psychosocial problems by specific types of treatments or interventions. It is crucial for the medical system to deal with the psychosocial aspects of cancer care in order to identify and deal with patients' needs for better compliance and adherence to treatment. The key of personalized holistic rehabilitation is multidisciplinary teamwork during the whole healing process: sharing the emotional experience also helps to prevent healthcare workers' burnout.
Subject(s)
Neoplasms , Quality of Life , Humans , Medical Oncology , Neoplasms/therapy , Psycho-OncologyABSTRACT
Organic anion-transporting polypeptide (OATP) 1B1/3-mediated drug-drug interaction (DDI) potential is evaluated in vivo with rosuvastatin (RST) as a probe substrate in clinical studies. We calibrated our assay with RST and estradiol 17-ß-D-glucuronide (E217ßG)/cholecystokinin-8 (CCK8) as in vitro probes for qualitative and quantitative prediction of OATP1B-mediated DDI potential for RST. In vitro OATP1B1/1B3 inhibition using E217ßG and CCK8 yielded higher area under the curve (AUC) ratio (AUCR) values numerically with the static model, but all probes performed similarly from a qualitative cutoff-based prediction, as described in regulatory guidances. However, the magnitudes of DDI were not captured satisfactorily. Considering that clearance of RST is also mediated by gut breast cancer resistance protein (BCRP), inhibition of BCRP was also incorporated in the DDI prediction if the gut inhibitor concentrations were 10 × IC50 for BCRP inhibition. This combined static model closely predicted the magnitude of RST DDI with root-mean-square error values of 0.767-0.812 and 1.24-1.31 with and without BCRP inhibition, respectively, for in vitro-in vivo correlation of DDI. Physiologically based pharmacokinetic (PBPK) modeling was also used to simulate DDI between RST and rifampicin, asunaprevir, and velpatasvir. Predicted AUCR for rifampicin and asunaprevir was within 1.5-fold of that observed, whereas that for velpatasvir showed a 2-fold underprediction. Overall, the combined static model incorporating both OATP1B and BCRP inhibition provides a quick and simple mathematical approach to quantitatively predict the magnitude of transporter-mediated DDI for RST for routine application. PBPK complements the static model and provides a framework for studying molecules when a dynamic model is needed. SIGNIFICANCE STATEMENT: Using 22 drugs, we show that a static model for organic anion-transporting polypeptide (OATP) 1B1/1B3 inhibition can qualitatively predict potential for drug-drug interaction (DDI) using a cutoff-based approach, as in regulatory guidances. However, consideration of both OATP1B1/3 and gut breast cancer resistance protein inhibition provided a better prediction of the magnitude of the transporter-mediated DDI of these inhibitors with rosuvastatin. Based on these results, we have proposed an empirical mechanistic-static approach for a more reliable prediction of transporter-mediated DDI liability with rosuvastatin that drug development teams can leverage.
Subject(s)
Liver-Specific Organic Anion Transporter 1/metabolism , Models, Biological , Rosuvastatin Calcium/pharmacokinetics , Solute Carrier Organic Anion Transporter Family Member 1B3/metabolism , ATP Binding Cassette Transporter, Subfamily G, Member 2/antagonists & inhibitors , ATP Binding Cassette Transporter, Subfamily G, Member 2/metabolism , Area Under Curve , Cholecystokinin/pharmacokinetics , Drug Evaluation, Preclinical , Drug Interactions , Estradiol/analogs & derivatives , Estradiol/pharmacokinetics , HEK293 Cells , Humans , Liver-Specific Organic Anion Transporter 1/antagonists & inhibitors , Neoplasm Proteins/antagonists & inhibitors , Neoplasm Proteins/metabolism , Peptide Fragments/pharmacokinetics , Solute Carrier Organic Anion Transporter Family Member 1B3/antagonists & inhibitorsABSTRACT
Progranulin is a glycoprotein marking chronic inflammation in obesity and type 2 diabetes. Previous studies suggested PSRC1 (proline and serine rich coiled-coil 1) to be a target of genetic variants associated with serum progranulin levels. We aimed to identify potentially functional variants and characterize their role in regulation of PSRC1. Phylogenetic module complexity analysis (PMCA) prioritized four polymorphisms (rs12740374, rs629301, rs660240, rs7528419) altering transcription factor binding sites with an overall score for potential regulatory function of Sall > 7.0. The effects of these variants on transcriptional activity and binding of transcription factors were tested by luciferase reporter and electrophoretic mobility shift assays (EMSA). In parallel, blood DNA promoter methylation of two regions was tested in subjects with a very high (N = 100) or a very low (N = 100) serum progranulin. Luciferase assays revealed lower activities in vectors carrying the rs629301-A compared with the C allele. Moreover, EMSA indicated a different binding pattern for the two rs629301 alleles, with an additional prominent band for the A allele, which was finally confirmed with the supershift for the Yin Yang 1 transcription factor (YY1). Subjects with high progranulin levels manifested a significantly higher mean DNA methylation (P < 1 × 10-7) in one promoter region, which was in line with a significantly lower PSRC1 mRNA expression levels in blood (P = 1 × 10-3). Consistently, rs629301-A allele was associated with lower PSRC1 mRNA expression (P < 1 × 10-7). Our data suggest that the progranulin-associated variant rs629301 modifies the transcription of PSRC1 through alteration of YY1 binding capacity. DNA methylation studies further support the role of PSRC1 in regulation of progranulin serum levels. KEY MESSAGES: PSRC1 (proline and serine rich coiled-coil 1) SNPs are associated with serum progranulin levels. rs629301 regulates PSRC1 expression by affecting Yin Yang 1 transcription factor (YY1) binding. PSRC1 is also epigenetically regulated in subjects with high progranulin levels.
Subject(s)
Gene Expression Regulation , Genetic Variation , Progranulins/genetics , Transcription, Genetic , Adult , Aged , Alleles , Cell Line , DNA Methylation , Epigenesis, Genetic , Female , Genes, Reporter , Genotype , Humans , Male , Middle Aged , Phylogeny , Polymorphism, Single Nucleotide , Progranulins/blood , Progranulins/metabolism , Protein Binding , RNA, Messenger/genetics , RNA, Messenger/metabolism , YY1 Transcription Factor/metabolismABSTRACT
Regulation of the parasympathetic nervous system, indexed through high frequency heart rate variability (HF-HRV), is indicative of physical and psychological health. However, little is known about the trainability of this capacity. We investigated the effects of a 9-month mental training program (the ReSource Project; n = 298) on voluntary HF-HRV upregulation, assessed with a novel biofeedback procedure. The program consisted of attentional, interoceptive, socio-affective and socio-cognitive training elements, all of which potentially influence parasympathetic regulation. Based on known links between oxytocin and parasympathetic activity, we also explored the relationship of HF-HRV upregulation to the oxytocin receptor system. We found that HF-HRV during the biofeedback session increased after 3 months of training, concomitant with prolonged respiration cycles. Breathing-controlled changes in HF-HRV upregulation, indicative of improved parasympathetic control, were significantly increased after 6 months of training. Homozygous risk allele carriers (AA) of the oxytocin receptor gene polymorphism rs53576 showed initially lower parasympathetic control, but fully compensated for their initial deficits through the training. No changes were found for HF-HRV at rest. Our data demonstrate that a mental training intervention extending over several months can increase the capacity for voluntary regulation of HF-HRV, with important implications for improving individual and societal health.
Subject(s)
Biofeedback, Psychology/methods , Heart Rate , Mental Healing , Parasympathetic Nervous System/physiology , Adult , Attention , Breathing Exercises , Female , Humans , Male , Polymorphism, Genetic , Receptors, Oxytocin/genetics , RespirationABSTRACT
In developed, developing and low-income countries alike, type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases, the severity of which is substantially a consequence of multiple organ complications that occur due to long-term progression of the disease before diagnosis and treatment. Despite enormous investment into the characterization of the disease, its long-term management remains problematic, with those afflicted enduring significant degradation in quality-of-life. Current research efforts into the etiology and pathogenesis of T2DM, are focused on defining aberrations in cellular physiology that result in development of insulin resistance and strategies for increasing insulin sensitivity, along with downstream effects on T2DM pathogenesis. Ongoing use of plant-derived naturally occurring materials to delay the onset of the disease or alleviate symptoms is viewed by clinicians as particularly desirable due to well-established efficacy and minimal toxicity of such preparations, along with generally lower per-patient costs, in comparison to many modern pharmaceuticals. A particularly attractive candidate in this respect, is fenugreek, a plant that has been used as a flavouring in human diet through recorded history. The present study assessed the insulin-sensitizing effect of fenugreek seeds in a cohort of human volunteers, and tested a hypothesis that melanin-concentrating hormone (MCH) acts as a critical determinant of this effect. A test of the hypothesis was undertaken using a hyperinsulinemic euglycemic glucose clamp approach to assess insulin sensitivity in response to oral administration of a fenugreek seed preparation to healthy subjects. Outcomes of these evaluations demonstrated significant improvement in glucose tolerance, especially in patients with impaired glucose responses. Outcome data further suggested that fenugreek seed intake-mediated improvement in insulin sensitivity correlated with reduction in MCH levels.
Subject(s)
Hypoglycemic Agents/pharmacology , Hypothalamic Hormones/blood , Insulin/metabolism , Melanins/blood , Pituitary Hormones/blood , Plant Extracts/pharmacology , Trigonella/chemistry , Adult , Female , Humans , Hypoglycemic Agents/administration & dosage , Insulin Resistance , Male , Middle Aged , Plant Extracts/administration & dosage , Seeds/chemistryABSTRACT
We report genome-wide ancient DNA from 44 ancient Near Easterners ranging in time between ~12,000 and 1,400 bc, from Natufian hunter-gatherers to Bronze Age farmers. We show that the earliest populations of the Near East derived around half their ancestry from a 'Basal Eurasian' lineage that had little if any Neanderthal admixture and that separated from other non-African lineages before their separation from each other. The first farmers of the southern Levant (Israel and Jordan) and Zagros Mountains (Iran) were strongly genetically differentiated, and each descended from local hunter-gatherers. By the time of the Bronze Age, these two populations and Anatolian-related farmers had mixed with each other and with the hunter-gatherers of Europe to greatly reduce genetic differentiation. The impact of the Near Eastern farmers extended beyond the Near East: farmers related to those of Anatolia spread westward into Europe; farmers related to those of the Levant spread southward into East Africa; farmers related to those of Iran spread northward into the Eurasian steppe; and people related to both the early farmers of Iran and to the pastoralists of the Eurasian steppe spread eastward into South Asia.
Subject(s)
Agriculture/history , Genomics , Human Migration/history , Phylogeny , Racial Groups/genetics , Africa, Eastern , Animals , Armenia , Asia , DNA/analysis , Europe , History, Ancient , Humans , Hybridization, Genetic/genetics , Iran , Israel , Jordan , Neanderthals/genetics , Phylogeography , TurkeyABSTRACT
Many diseases nowadays are assumed to be genetically determined. Therefore, many knockout mouse models have been established and are widely used. Unfortunately, nutrition (in particular the fat content of food) is often neglected in studies on these disease models. In this study the effects of nutrition on the lipid (triacylglycerol, TAG) compositions of different mouse adipose tissues were investigated. Mice were subjected to different diets [high fat (HF) vs. standard diet (SD)] and different adipose tissue samples (brown, visceral, and subcutaneous fat) were isolated after 12 weeks. Subsequent to lipid extraction, the organic extracts were analyzed by mass spectrometry (MALDI and ESI), high-resolution (1)H and (31)P NMR spectroscopy, high-performance thin-layer chromatography (HPTLC), and gas chromatography (GC). In adipose tissue of mice fed with HF diet, (a) decreased double bond contents and (b) decreased fatty acyl chain lengths of tissue TAGs were observed; this trend could be concomitantly monitored by all methods used. However, the adipose tissue still contained significant amounts of slightly unsaturated fatty acyl residues (18:1). Thus, a certain double bond content seems necessary to maintain the properties of adipose tissues.
Subject(s)
Adipose Tissue/chemistry , Diet, High-Fat , Lipids/analysis , Triglycerides/analysis , Adipose Tissue/metabolism , Animals , Chromatography, Gas , Chromatography, Thin Layer , Dietary Fats/analysis , Dietary Fats/metabolism , Fatty Acids, Unsaturated/analysis , Fatty Acids, Unsaturated/metabolism , Lipid Metabolism , Magnetic Resonance Spectroscopy , Male , Mice , Spectrometry, Mass, Electrospray Ionization , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Triglycerides/metabolismABSTRACT
Pharmacological and functional data suggest the existence of uridine (Urd) receptors in the central nervous system (CNS). In the present study, simultaneous extracellular single unit recording and microiontophoretic injection of the pyrimidine nucleoside Urd was used to provide evidence for the presence of Urd-sensitive neurons in the thalamus and the cerebral cortex of Long Evans rats. Twenty-two neurons in the thalamus (24% of recorded neurons) and 17 neurons in the cortex (55%) responded to the direct iontophoresis of Urd. The majority of Urd-sensitive neurons in the thalamus and cortex (82% and 59%, respectively) increased their firing rate in response to Urd. In contrary, adenosine (Ado) and uridine 5'-triphosphate (UTP) decreased the firing rate of all responding neurons in the thalamus, and the majority of responding neurons in the cortex (83% and 87%, respectively). Functional relevance of Urd-sensitive neurons was investigated in spontaneously epileptic freely moving Long Evans and Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. Intraperitoneal (i.p.) injection of 500mg/kg Urd decreased epileptic activity (210-270min after injection) in both rat strains. Intraperitoneal administration of 1000mg/kg Urd decreased the number of spike-wave discharges (SWDs) between 150-270min and 90-270min in Long Evans and WAG/Rij rats, respectively. The effect of Urd was long-lasting in both rat strains as the higher dose significantly decreased the number of SWDs even 24h after Urd injection. The present results suggest that Urd-sensitive neurons in the thalamus and the cerebral cortex may play a role in the antiepileptic action of Urd possibly via modulation of thalamocortical neuronal circuits.
Subject(s)
Anticonvulsants/pharmacology , Neural Inhibition , Neurons/drug effects , Uridine/pharmacology , Animals , Cerebral Cortex/drug effects , Cerebral Cortex/physiology , Epilepsy, Absence/physiopathology , Male , Neurons/physiology , Rats , Rats, Long-Evans , Rats, Wistar , Thalamus/drug effects , Thalamus/physiologyABSTRACT
Coffee is the most commonly used stimulant and caffeine is its main psychoactive ingredient. The heritability of coffee consumption has been estimated at around 50%. We performed a meta-analysis of four genome-wide association studies of coffee consumption among coffee drinkers from Iceland (n = 2680), The Netherlands (n = 2791), the Sorbs Slavonic population isolate in Germany (n = 771) and the USA (n = 369) using both directly genotyped and imputed single nucleotide polymorphisms (SNPs) (2.5 million SNPs). SNPs at the two most significant loci were also genotyped in a sample set from Iceland (n = 2430) and a Danish sample set consisting of pregnant women (n = 1620). Combining all data, two sequence variants significantly associated with increased coffee consumption: rs2472297-T located between CYP1A1 and CYP1A2 at 15q24 (P = 5.4 · 10(-14)) and rs6968865-T near aryl hydrocarbon receptor (AHR) at 7p21 (P = 2.3 · 10(-11)). An effect of â¼0.2 cups a day per allele was observed for both SNPs. CYP1A2 is the main caffeine metabolizing enzyme and is also involved in drug metabolism. AHR detects xenobiotics, such as polycyclic aryl hydrocarbons found in roasted coffee, and induces transcription of CYP1A1 and CYP1A2. The association of these SNPs with coffee consumption was present in both smokers and non-smokers.
Subject(s)
Coffee/metabolism , Cytochrome P-450 CYP1A1/genetics , Cytochrome P-450 CYP1A2/genetics , Drinking Behavior/physiology , Genetic Variation , Receptors, Aryl Hydrocarbon/genetics , Adult , Aged , Alleles , Chromosomes, Human, Pair 15 , Female , Genome-Wide Association Study , Humans , Male , Middle Aged , Models, Biological , Polymorphism, Single Nucleotide , Promoter Regions, Genetic/genetics , Sex FactorsABSTRACT
Elevated visceral adipose tissue-derived serpin (vaspin) serum concentrations are associated with impaired insulin sensitivity, but increase unexpectedly after long-term physical training. We therefore investigated the effect of an acute exercise bout and the effects of vitamin supplementation on chronic exercise effect and on serum vaspin concentrations. We measured serum vaspin and thiobarbituric acid-reactive substances (TBARS) concentrations in 80 individuals before and after a 1-hour acute exercise bout and independently in 40 healthy young men who were randomly assigned to either antioxidant (vitamin C (1,000 mg/day) and vitamin E (400 IU/day)) or to no supplementation after a standardized 4-week physical training program as a post hoc analysis. Serum vaspin concentrations significantly decreased after acute physical exercise as well as after 4 weeks of training in individuals without antioxidants. Changes in vaspin serum concentration correlate with increased TBARS serum concentrations both in response to a 1-hour exercise bout (r = -0.42, p < 0.01) and to the 4-week training (r = -0.31, p < 0.05). Interestingly, supplementation with antioxidants rather increased circulating vaspin levels in response to 4 weeks of exercise. In conclusion, vaspin serum concentrations are decreased by exercise-induced oxidative stress, but not by exercise-associated improvement in insulin sensitivity.
Subject(s)
Antioxidants/therapeutic use , Dietary Supplements , Exercise/physiology , Oxidative Stress/drug effects , Serpins/blood , Vitamins/therapeutic use , Adult , Ascorbic Acid/therapeutic use , Biomarkers/blood , Blood Glucose/metabolism , Down-Regulation , Female , Germany , Humans , Insulin/blood , Male , Reactive Oxygen Species/metabolism , Thiobarbituric Acid Reactive Substances/metabolism , Time Factors , Treatment Outcome , Vitamin E/therapeutic use , Young AdultABSTRACT
The responses to adenosine were studied on isolated, methacholine-precontracted tracheal strips of guinea pigs in the course of long-term caffeine or solvent treatment. Guinea pigs were fed caffeine for 10 weeks (average serum caffeine concentration: 39.1 +/- 3.9 microM). In epithelium-intact tracheal preparations (EITPs), sensititization to adenosine-induced relaxation (AIR) developed. It attained a maximum in week 1 of caffeine treatment, and then its level diminished and disappeared completely by weeks 4 - 6. In epithelium-denuded tracheal preparations (EDTPs), an increase in the sensitivity to adenosine was observed from week 1 to week 10 (a 4 - 6-fold reduction in EC50). Use of a coaxial bioassay system confirmed the role of epithelium in this process. The enhancement of the AIR of the EITPs was not modified by inhibitors of cyclooxygenase and lipoxygenase. Following depletion of the neuropeptides by acute capsaicin pretreatment, the AIR of the EITPs was strongly enhanced after caffeine treatment for 6 weeks. In chronically caffeine-treated EITPs, the inhibition of neutral endopeptidase led to dramatic reduction of the AIR. On the basis of the results by inhibiting nitric oxide synthase, it can be supposed that nitric oxide released from EITPs of long-lasting caffeine-treated animals operated as a constrictor agent. Our results show that chronic caffeine treatment gives rise to an initial sensitization to adenosine of the EITPs, this being followed by the development of a specific adaptive process in the epithelial cells, which counterbalances the increased tracheal sensitivity to adenosine.
Subject(s)
Adenosine/pharmacology , Caffeine/pharmacology , Epithelium/physiology , Trachea/drug effects , Animals , Body Weight/drug effects , Caffeine/blood , Capsaicin/pharmacology , Cromolyn Sodium/pharmacology , Guinea Pigs , In Vitro Techniques , Male , Muscle Relaxation/drug effects , Nitric Oxide/physiology , Nitroarginine/pharmacology , Trachea/physiologyABSTRACT
Although mast cells are immune cells of hematopoietic origin, they can be found in parts of the central nervous system of many mammalian species. In the rat brain they are located in the thalamic region. Their function is not defined yet, although they are mostly known to secrete several chemicals, which may influence the surrounding neurons. There are no in vivo electrophysiological data available on the possible effects of brain mast cells on neurons. In this study, we used a combined method of microiontophoresis and extracellular single unit recording to simultaneously activate mast cells and record neuronal action potentials. Four-barrelled micropipettes were used for recording neuronal activity and for microiontophoretic application of mast cell degranulator Compound 48/80 (C48/80). Spike sorting routines were performed on-line and off-line to ensure that data were always recorded from a single neuron. C48/80 did not modify the firing rate of cortical neurons (no mast cells are found there), however, it caused excitation (n = 16/37, 43%), or inhibition (n = 9/37, 24%) in thalamic neurons possibly due to mast cell activation. Further investigations will clarify the biochemical nature of changes in neural excitability due to mast cell degranulation in the mammalian brain.
Subject(s)
Brain/cytology , Iontophoresis/methods , Mast Cells/cytology , Mast Cells/physiology , Neurons/cytology , Neurons/physiology , Action Potentials , Animals , Brain/drug effects , Brain/physiology , Cell Communication/drug effects , Cell Degranulation/drug effects , Female , Mast Cells/drug effects , Rats , Rats, Long-Evans , Thalamus/cytology , Thalamus/drug effects , Thalamus/physiology , p-Methoxy-N-methylphenethylamine/pharmacologyABSTRACT
Single cell unit activity of 187 neurons of 24 rats were analysed to study the possible involvement of intracranial mast cells on modifying thalamic neuronal activity. Mast cells were activated with microiontophoretical application of compound 48/80. This substance did not modify the firing rate of cortical or hippocampal neurons (no mast cells are found here), however it caused excitation (70% in females, 11% in males), or inhibition (7% in females, 33% in males) on thalamic neurons, possibly due to mast cell activation. In consecutive anatomical evaluation many partially or fully degranulated mast cells were found in the recorded thalamic areas.