Neuropeptide Y Concentrations Research Articles

Development of a Neuropeptide Y-Sensitive Implantable Microelectrode for Continuous Measurements.

In this work, we present the development of the first implantable aptamer-based platinum microelectrode for continuous measurement of a nonelectroactive molecule, neuropeptide Y (NPY). The aptamer immobilization was performed via conjugation chemistry and characterized using cyclic voltammetry before and after the surface modification. The redox label, methylene blue (MB), was attached at the end of the aptamer sequence and characterized using square wave voltammetry (SWV). NPY standard solutions in a three-electrode cell were used to test three aptamers in steady-state measurement using SWV for optimization. The aptamer with the best performance in the steady-state measurements was chosen, and continuous measurements were performed in a flow cell system using intermittent pulse amperometry. Dynamic measurements were compared against confounding and similar peptides such as pancreatic polypeptide and peptide YY, as well as somatostatin to determine the selectivity in the same modified microelectrode. Our Pt-microelectrode aptamer-based NPY biosensor provides signals 10 times higher for NPY compared to the confounding molecules. This proof-of-concept shows the first potential implantable microelectrode that is selectively sensitive to NPY concentration changes.

Relation of plasma neuropeptide-Y with myocardial function and infarct severity in acute ST-elevation myocardial infarction

BackgroundAcute myocardial infarction is associated with the release of the co-transmitter neuropeptide-Y (NPY). NPY acts as a potent vasoconstrictor and is associated with microvascular dysfunction after ST-elevation myocardial infarction (STEMI). This study comprehensively evaluated the association of plasma NPY with myocardial function and infarct severity, visualized by cardiac magnetic resonance (CMR) imaging, in STEMI patients revascularized by primary percutaneous coronary intervention (PCI). MethodsIn this observational study, we included 260 STEMI patients enrolled in the prospective MARINA-STEMI (NCT04113356) study. Plasma NPY concentrations were measured by an immunoassay 24h after PCI from peripheral venous blood samples. Left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), infarct size (IS) and microvascular obstruction (MVO) were determined using CMR imaging. ResultsMedian plasma concentrations of NPY were 70 [interquartile range (IQR):35-115] pg/ml. NPY levels above median were significantly associated with lower LVEF (48%vs.52%, p=0.004), decreased GLS (-8.8%vs.-12.6%, p<0.001) and larger IS (17%vs.13%, p=0.041) in the acute phase after infarction as well as after 4 months (LVEF:50%vs.52%, p=0.030, GLS:-10.5vs.-12.9,p<0.001,IS:13%vs.10%,p=0.011). In addition, NPY levels were significantly related to presence of MVO (58%vs.52%, p=0.041). Moreover, in multivariable linear regression analysis, NPY remained significantly associated with all investigated CMR parameters (LVEF:p<0.001,GLS:p<0.001,IS:p=0.003,MVO:p=0.042) independent of other established clinical variables including high-sensitivity cardiac troponin T, pre-interventional TIMI flow 0 and left anterior descending artery as culprit lesion location. ConclusionHigh plasma levels of NPY, measured 24h after STEMI, were independently associated with lower LVEF, decreased GLS, larger IS as well as presence of MVO, indicating plasma NPY as a novel clinical risk marker post STEMI.

Both coiling and clipping induce the time-dependent release of endogenous neuropeptide Y into serum.

The vaso- and psychoactive endogenous Neuropeptide Y (NPY) has repeatedly been shown to be excessively released after subarachnoid hemorrhage and in numerous psychiatric disorders. NPY is stored in sympathetic perivascular nerve fibers around the major cerebral arteries. This prospective study was designed to analyze the impact of microsurgical and endovascular manipulation of the cerebral vasculature versus cranio- and durotomy alone on the serum levels of NPY. 58 patients (drop-out n = 3; m:f = 26:29; mean age 52.0 ± 14.1 years) were prospectively enrolled. The vascular group underwent repair for unruptured intracranial aneurysms (UIA) of the anterior circulation [endovascular aneurysm occlusion (EV) n = 13; microsurgical clipping (MS) n = 17]; in the non-vascular group, 14 patients received microsurgical resection of a small-sized convexity meningioma (CM), and 11 patients with surgically treated degenerative lumbar spine disease (LD) served as control. Plasma was drawn (1) before treatment (t0), (2) periprocedurally (t1), (3) 6 h postprocedurally (t2), (4) 72 h postprocedurally (t3), and (5) at the 6-week follow-up (FU; t4) to determine the NPY levels via competitive enzyme immunoassay in duplicate serum samples. We statistically evaluated differences between groups by calculating one-way ANOVA and for changes along the time points using repeated measure ANOVA. Except for time point t0, the serum concentrations of NPY ranged significantly higher in the vascular than in the non-vascular group (p < 0.001), with a slight decrease in both vascular subgroups 6 h postprocedurally, followed by a gradual increase above baseline levels until FU. At t3, the EV subgroup showed significantly higher NPY levels (mean ± standard deviation) than the MS subgroup (0.569 ± 0.198 ng/mL vs. 0.415 ± 0.192 ng/mL, p = 0.0217). The highest NPY concentrations were measured in the EV subgroup at t1, t3, and t4, reaching a climax at FU (0.551 ± 0.304 ng/mL). Our study reveals a first insight into the short-term dynamics of the serum levels of endogenous NPY in neurosurgical and endovascular procedures, respectively: Direct manipulation within but also next to the major cerebral arteries induces an excessive release of NPY into the serum. Our findings raise the interesting question of the potential capacity of NPY in modulating the psycho-behavioral outcome of neurovascular patients.

Increasing NPYergic transmission in the hippocampus rescues aging-related deficits of long-term potentiation in the mouse dentate gyrus.

Loss of neuropeptide Y (NPY)-expressing interneurons in the hippocampus and decaying cholinergic neuromodulation are thought to contribute to impaired cognitive function during aging. However, the interaction of these two neuromodulatory systems in maintaining hippocampal synaptic plasticity during healthy aging has not been explored so far. Here we report profound sex differences in the Neuropeptide-Y (NPY) levels in the dorsal dentate gyrus (DG) with higher NPY concentrations in the male mice compared to their female counterparts and a reduction of NPY levels during aging specifically in males. This change in aged males is accompanied by a deficit in theta burst-induced long-term potentiation (LTP) in the medial perforant path-to-dorsal DG (MPP-DG) synapse, which can be rescued by enhancing cholinergic activation with the acetylcholine esterase blocker, physostigmine. Importantly, NPYergic transmission is required for this rescue of LTP. Moreover, exogenous NPY application alone is sufficient to recover LTP induction in aged male mice, even in the absence of the cholinergic stimulator. Together, our results suggest that in male mice NPYergic neurotransmission is a critical factor for maintaining dorsal DG LTP during aging.

Label-Free Neuropeptide Detection beyond the Debye Length Limit.

Biosensors with high selectivity, high sensitivity, and real-time detection capabilities are of significant interest for diagnostic applications as well as human health and performance monitoring. Graphene field-effect transistor (GFET) based biosensors are suitable for integration into wearable sensor technology and can potentially demonstrate the sensitivity and selectivity necessary for real-time detection and monitoring of biomarkers. Previously reported DC-mode GFET biosensors showed a high sensitivity for sensing biomarkers in solutions with a low salt concentration. However, due to Debye length screening, the sensitivity of the DC-mode GFET biosensors decreases significantly during operation in a physiological fluid such as sweat or interstitial fluid. To overcome the Debye screening length limitation, we report here alternating current (AC) mode heterodyne-based GFET biosensors for sensing neuropeptide-Y (NPY), a key stress biomarker, in artificial sweat at physiologically relevant ionic concentrations. Our AC-mode GFET biosensors show a record ultralow detection limit of 2 × 10-18 M with an extensive dynamic range of 10 orders of magnitude in sensor response to target NPY concentration. The sensors were characterized for various carrier frequencies (ranging from 30 kHz to 2 MHz) of the applied AC voltages and various salt concentrations (10, 50, and 100 mM). Contrary to DC-mode sensing, the AC-mode sensor response increases with an increase in salt concentration in the electrolyte. The sensor response can be further enhanced by tuning the carrier frequency of the applied AC voltage. The optimum response frequency of our sensor is approximately 400-600 kHz for salt concentrations of 50 and 100 mM, respectively. The salt-concentration- and frequency-dependent sensor response can be explained by an electrolyte-gated capacitance model.

Optimized formula for the hybrid abalone Haliotis discus hannai♀ × H. fulgens♂: Betaine supplementation increases the use of rice bran meal as a replacement for kelp

Two trials were conducted to determine the optimal replacement level of rice bran meal (RBM) as a substitute for kelp meal (KM) in the diet of the hybrid abalone Haliotis discus hannai ♀ × H. fulgens ♂. This study also investigated whether betaine as an attractant supplementation could be used to facilitate RBM as a replacement for KM. In Trial 1, RBM was used to replace 25%, 50%, and 100% of the dietary KM (RBM25, RBM50, and RBM100, respectively) based on a diet containing 30% KM (Con). In Trial 2, RBM50 was the same as in Trial 1, and betaine was supplemented in RBM50 at 0.2% (B1), 0.4% (B2), and 0.8% (B3) in the diets. Abalone (weight approximately 4 g) were randomly assigned to four groups replicated in triplicate (60 abalone/replicate). The abalone were fed the experimental diets for 10 weeks. In Trial 1, compared to the Con group, no significant differences were observed in final weight (FW), final shell length (FSL), specific growth rate (SGR), or daily increment in shell length (DISL) at 25% KM replacement by RBM. However, 50% KM replacement significantly reduced the FW, FSL, SGR, and DISL compared to the Con group. There were no significant differences in the proximate composition of the soft body tissues of the abalone. In Trial 2, growth performance parameters of the hybrid abalone were significantly improved with increasing levels of betaine in the diets compared to those fed diet RBM50, reaching the maximum value in the B2 group. Consistent with the feed intake results, the hormone concentrations of neuropeptide Y (NPY) and orexins in the digestive gland and cerebral ganglia of abalone were significantly increased when the supplementation level of betaine in the diets was increased to 0.2%. However, no apparent impacts were observed on NPY or orexin concentrations among the B1, B2, and B3 groups. Finally, we suggest 0.4% betaine supplementation along with replacing 50% of the KM with RBM in the hybrid abalone diet. The optimal diet is a cost-effective alternative feed formulation that can reduce the dependence on KM for abalone production in China. This study also demonstrates the potential of betaine as a feed attractant in abalone aquaculture.

Neuropeptide Y directly reduced apoptosis of granulosa cells, and the expression of NPY and its receptors in PCOS subjects

BackgroundMost women with anovulatory infertility show polycystic ovarian syndrome (PCOS), and androgen excess is known as a key factor involved in pathogenicity of PCOS. However, the mechanism of follicular developmental arrest in PCOS is not completely understood. The reproductive function of Neuropeptide Y (NPY) in the ovary during folliculogenesis was previously reported; NPY function in apoptosis and proliferation of granulosa cells (GCs) is follicular-stage dependent. The objective of this study was to investigate the role of NPY in ovarian follicular development and the pathogenesis of PCOS.MethodsTo simulate the PCOS phenotype using a rat model, 21-day old Sprague Dawley rats were implanted with dihydrotestosterone (DHT) capsule (83 µg/day) and euthanized after 28 days. mRNA and protein content of NPY and its receptors were assessed in GCs from DHT treated rats using RT-qPCR and Western blot, respectively. Proliferation and apoptosis of GCs was assessed using Ki67- and TUNEL assays. Finally, NPY levels were measured in human follicular fluid (FF) from matched PCOS and non-PCOS patients using ELISA.ResultsGCs from DHT treated rats (PCOS-GCs) contained significantly less NPY protein and Npy mRNA by 0.16- and 0.56-fold, respectively, and more NPY receptor type 2 and 5 protein by 2.21- and 3.17-fold, respectively, when compared to sham control. Addition of recombinant NPY to PCOS-GCs culture did not alter Ki67-positive but significantly decreased TUNEL-positive cells by 0.65-fold, but not to baseline levels. There was no significant difference in NPY levels in FF between PCOS and non-PCOS subjects.ConclusionsThese results indicate that DHT modulates expression of NPY and its receptors, NPY decreases DHT-induced GCs apoptosis. That alterations in NPY’s function might be involved in follicular developmental failure of PCOS.

Transient cardiac electrophysiological changes in a rat model of subarachnoid haemorrhage: a brain-heart interaction.

Subarachnoid haemorrhage (SAH) is one of the causes of sudden cardiac death (SCD). However, the time course of ventricular arrhythmias and potential mechanisms responsible for this effect after SAH remain unknown. This study aims to investigate the effect of SAH on ventricular electrophysiological changes and its potential mechanisms in long-term phase. We examined the ventricular electrophysiological remodelling and potential mechanisms in a Sprague Dawley rat model of SAH at six time points (baseline, and Days 1, 3, 7, 14 and 28) and explored the potential mechanisms. We measured the ventricular effective refractory period (ERP), ventricular fibrillation threshold (VFT) and left stellate ganglion (LSG) activity at different time points before and after SAH. We also detected neuropeptide Y (NPY) levels in plasma and myocardial tissues by enzyme-linked immunosorbent assay, and quantified NPY 1 receptor (NPY1R) protein and mRNA expression levels by western blotting and quantitative real-time reverse transcription-polymerase chain reaction, respectively. Subarachnoid haemorrhage gradually prolonged QTc intervals, shortened ventricular ERP and reduced VFT during the acute phase, peaking at Day 3. However, no significant changes were observed from Days 14 to 28 compared to Day 0. Subarachnoid haemorrhage gradually increased LSG activity, increased NPY concentrations and up-regulated NPY1R expression in the acute phase of SAH, peaking at Day 3. However, no significant variations were found from Days 14 to 28 compared to Day 0. Subarachnoid haemorrhage increases the transient susceptibility of VAs in the acute phase, and the underlying mechanisms for this response included increased sympathetic activity and up-regulated NPY1R expression.

(231) Endogenous Vasoactive Peptides in the Control of Human Penile Erectile Tissue: Is There a Significance of the Neuropeptide Y (NPY)?

Abstract Introduction Aside from the neurotransmitters of the sympathetic adrenergic system, vasoconstrictor peptides may also play a role in mediating the constant tone of the erectile tissue during penile flaccidity and in returning the erect penis to the flaccid state. Neuropeptide Y (NPY) is present in high concentrations in the male genital tract. The peptide has been shown to induce contraction of isolated human penile tissue (corpus cavernosum, penile arteries) and potentiate its response to noradrenaline. Objective The purpose of our study was to measure in the cavernous and systemic blood of healthy male volunteers the course of NPY through different stages of sexual arousal. Methods Whole blood was drawn from the corpus cavernosum and the cubital vein of 15 healthy male volunteers during penile flaccidity (Fl), tumescence (Tu), rigidity (Ri) and detumescence (Det). Penile tumescence and erection were induced by applying audiovisual and tactile stimulation. Plasma levels of NPY (given in pmol/L) were determined by means of an enzyme-linked immunoassay (ELISA, IBL GmbH, Hamburg, Germany). Results NPY significantly decreased in the cavernous blood with the beginning of sexual arousal, when the flaccid penis became tumescent and finally rigid (Fl: 88.8 ± 35.8, Tu: 62.4 ± 22.7, Ri: 62.3 ± 19.7). In the phase of detumescence, only a slight increase was noted (64.8 ± 23). In the systemic circulation, no pronounced alterations in the concentration of NPY were registered through the different penile stages (Fl: 64.4 ± 27, Tu: 65.8 ± 19, Ri: 59.6-25, Det: 67.6 ± 29.3). Conclusions Our findings are in favor of the hypothesis that NPY could contribute to the maintenance of the resting state of cavernous smooth muscle. It remains to be elucidated whether the peptide may play a role in the pathophysiology of erectile dysfunction. Disclosure No

Neuropeptide Y Promotes the Treatment of Adipose Stem Cells on Type 2 Diabetic Wounds.

Type 2 diabetes (T2D) is a common metabolic disorder. Due to insufficient insulin secretion or insulin resistance, increased blood glucose often leads to impaired wound healing in T2D patients. Our previous research showed that adipose-derived stem cells (ASCs) from normal mice and T2D mice improved the cutaneous wound healing of diabetic mice. We also found that the expression of neuropeptide Y (NPY) in T2D ASCs was significantly decreased. In order to explore the effects of NPY on ASCs and diabetic wound healing, we investigated the effects of NPY on ASCs proliferation and growth factors expression and secretion, the effects of NPY on skin fibroblasts, and the effects of NPY combined with ASCs on T2D wound healing. The results showed that a certain concentration of NPY could promote the proliferation and the growth factors expression and secretion of ASCs, and promote the proliferation and migration of fibroblasts. At the same time, NPY and ASCs have a synergistic effect, which can promote wound healing and decrease inflammation in T2D wounds. NPY may regulate ASCs through the ERK pathway. These results are conducive to promoting ASCs and NPY in the treatment of diabetic wounds. NPY can promote the effect of ASCs in the treatment of diabetic wounds.

Elevated Neuropeptide Y in the Arcuate Nucleus of Young Obese Zucker Rats May Contribute to the Development of Their Overeating

Neuropeptide Y (NPY) mediates feeding behavior through a local hypothalamic network formed by the arcuate and paraventricular nuclei (the AP axis). In the hypothalamus, NPY is mainly synthesized in neurons of the arcuate nucleus. These neurons project to the paraventricular nucleus, the site where NPY has the strongest stimulatory effects on food intake of Sprague-Dawley rats. In the adult Zucker fatty rat (a genetic model of obesity with a well-established hyperphagia), NPY concentrations in these nuclei are higher than in its lean counterpart. We measured hypothalamic NPY before the appearance of altered eating behavior, e.g., in very young (16-d-old) lean and obese Zucker pups, and in pups at an age when overeating had begun, e.g., a few days after weaning at 30 d. At 30 d, NPY concentrations were significantly higher in obese than in lean rats in the arcuate nucleus (14.2 +/- 0.7 vs. 11.6 +/- 0.5 pmol/mg protein, P < 0.01). This difference was not observed at 16 d. A 160% increase was noted in the paraventricular nuclei of obese rats between 16 and 30 d of life compared with a 100% increase in the lean rats (P < 0.001). Neuropeptide Y concentration was greater in 30-d-old rats than in 16-d-old rats in other areas involved in the regulation of feeding behavior, such as the dorsomedian nuclei and lateral hypothalamus, but the values did not differ between genotypes. Higher NPY concentration was therefore detected early in young obese rats in the main hypothalamic site of NPY synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Bowls-unblocking and mind-regulating acupuncture therapy for constipation-predominant irritable bowel syndrome: An exploratory randomized clinical trial 通腑调神针法治疗便秘型肠易激综合征:随机对照试验

ObjectiveTo observe the effects of bowls-unblocking and mind-regulating acupuncture therapy on constipation, anxiety, depression and serum neuropeptide Y (NPY) content for the patients with constipation-predominant irritable bowel syndrome (IBS-C). MethodsForty-two IBS-C patients were randomly assigned either into a bowls-unblocking and mind-regulating acupuncture group (acupuncture group) or a mosapride citrate group (medication group) with 21 cases in each group. During the treatment, one patient in the medication group was excluded and 20 patients were included in final statistical analysis; while 21 patients completed the trial in the acupuncture group. Before treatment, after treatment and in follow-up (1 month after the whole treatment), the scores of the Cleveland clinical constipation scoring system (CCS), the self-rating anxiety scale (SAS), and the self-rating depression scale (SDS) were assessed in both groups. The changes in NPY content were compared before and after treatment. Results① Total score of CCS: after treatment, the total score in the acupuncture group and the medication group were (4.76 ± 2.10) points and (5.60 ± 1.88) points, respectively, which were significantly lower than those before treatment in both groups (both P < 0.05); and the difference in the score was not significant for the between-group comparison (P > 0.05). In the follow-up, the total scores were (4.19 ± 1.69) points in the acupuncture group, and was (6.35 ± 2.06) points in the medication group. The score in the medication group was higher than that after treatment in the same group (P < 0.05), but there was no significant difference between acupuncture group and the medication group (P > 0.05). ② SAS score: after treatment, the SAS scores were (50.24 ± 2.19) points and (53.45 ± 2.46) points in the acupuncture group and the medication group, respectively, which was lower than that before treatment in the two groups (both P < 0.05); and the difference in the score was significant between two groups (P < 0.05). In the follow-up, the scores were (51.95 ± 2.27) points and (54.55 ± 1.67) points in the acupuncture group and the medication group, respectively; which was lower than that before treatment in the two groups (both P < 0.05), and the difference in the score was significant between two groups (P < 0.05). ③SDS score: after treatment, the SDS scores were (50.71 ± 2.70) points and (53.15 ± 2.25) points in the acupuncture group and the medication group, respectively, which was significantly lower than that before treatment in the two groups (both P < 0.05); and the difference in the score was significant between the two group (P < 0.05). In the follow-up, the score of the acupuncture group was (52.57 ± 3.72) points and it was (56.60 ± 2.42) points in the medication group, which was significantly lower than that before treatment in the two groups (both P < 0.05); and the difference in the score was significant between the two groups (P < 0.05). ④Comparison of serum NPY content: after treatment, the serum NPY content of the acupuncture group and the medication group were (7.08 ± 3.02) mmol/L and (9.89 ± 3.82) mmol/L, respectively, which was significantly lower than that before treatment within each group (both P < 0.05). The difference was significant between the two groups (P < 0.05). ⑤ Effective rate: after treatment, the total effective rate was 95.24% in the acupuncture group and 90.00% in the medication group, without statistically significant difference (P > 0.05). Conclusionsbowls-unblocking and mind-regulating acupuncture therapy relieved the defecation-related symptoms, anxiety, and depression in IBS-C patients; and it was more effective on abdominal pain compared with mosapride citrate. Acupuncture therapy also had some long-term effect, which may be related to its regulatory effect on the serum NPY content.

Dextrose Prolotherapy for Symptomatic Grade IV Knee Osteoarthritis: A Pilot Study of Early and Longer-Term Analgesia and Pain-Specific Cytokine Concentrations.

Neurocytokines may upregulate or downregulate neuropathic pain. We hypothesized that dextrose (D-glucose) injections for therapeutic purposes (dextrose prolotherapy: DPT) in painful knee osteoarthritis (KOA) would favorably affect synovial-fluid neurocytokine concentrations. Twenty participants with grade IV symptomatic KOA received synovial-fluid aspiration followed by dextrose or simulated dextrose injections, followed by the reverse after one week. All participants then received open-label dextrose injections monthly for 6 months, with serial assessments of walking pain at 20 min for 9 months, as well as synovial-neurocytokine-concentration measurements (calcitonin gene-related peptide, substance P (SP), and neuropeptide Y (NPY)) at one week and three months. Clinically important analgesia was observed at 20 min and for 9 months post dextrose injection. One -week synovial-fluid SP concentration rose by 111% (p = 0.028 within groups and p = 0.07 between groups) in the dextrose-injected knees compared to synovial-fluid aspiration only. Three-month synovial-fluid NPY concentration dropped substantially (65%; p &lt; 0.001) after open-label dextrose injection in all knees. Prompt and medium-term analgesia after intra-articular dextrose injection in KOA was accompanied by potentially favorable changes in synovial-fluid neurocytokines SP and NPY, respectively, although these changes were isolated. Including neurocytokines in future assessments of DPT to elucidate mechanisms of action is recommended.

Fabrication of Aptamer-Modified Microelectrodes for Npy Detection in Artificial Cerebrospinal Fluid Using Methylene Blue As Electrochemical Signal Amplifier

In recent years microelectrodes (ME) have been a great tool in the study of neuroscience. Microelectrodes are often used in neurotransmission research due to characteristics such as their small diameter, electrochemical capabilities, and compatibility with quick electrochemical procedures. Using methylene blue (MB) as an electrochemical signal amplifier allows us to assess adsorption of Neuropeptide Y (NPY) on the electrode surface in artificial cerebrospinal fluid (aCSF) with a pH of 7.4. Electrochemistry has a number of significant benefits over other methods of detection. One of these benefits is the ability to monitor a variety of molecules rather than only those that oxidize or decrease by changing the electrodes' material and altering their surfaces to provide selectivity toward the biomolecule of interest. In order to measure NPY using aptamer-modified microelectrodes with MB we first must prepare the microelectrodes by aspirating a platinum fiber into a quartz material and creating a connection. These are then cleaned electrochemically and characterized bare before being left in an aptamer solution to be modified. Then they are characterized again and left in a MB solution to complete the modifications. We were able to see the difference between the bare and modified electrodes during the characterizations as well as a constant peak of MB through the use of Square Wave Voltammetry (SWV) when characterized in aCSF which leads us to conclude that our method is successful in measuring and detecting different concentrations of NPY. We were able to measure NPY at varying concentrations ranging from 1 to 1000 pg/ml. This was observed as a reduction of the signal of the MB peak as the concentration of NPY is increased.

Npy Selectivity on Methylene Blue Aptamer-Modified Microelectrodes

Over the past 50 years, there has been a significant improvement in our understanding of neurotransmitters, especially in relation to depression, schizophrenia, Parkinson's disease, and Alzheimer's disease. However, little is known about how neuropeptides are released and work, and much of their activity is inferred through indirect observations. Since neuropeptides are non-electroactive molecules and are therefore challenging to detect, it is essential to develop an analytical approach for measuring them. The most prevalent neuropeptide in the brain is called neuropeptide Y (NPY), and it has been linked to a wide range of biological functions and diseases, including post-traumatic stress disorder (PTSD), depression, anxiety, obesity, alcoholism, mood swings, and eating disorders. There is currently no technology for measuring NPY in the brain with great temporal and spatial resolution. In order to comprehend the process in which NPY is engaged, we thus proposed the building of a biological sensor. This study focuses on affinity-mediated electrochemical techniques for NPY detection and measurement. In order to take advantage of the affinity between Pt and a thiol group in the aptamer structure, an aptamer—a short single-stranded DNA with high affinity by NPY—was connected to a Pt surface of a microelectrode. The aptamer was then conjugated to a redox molecule, such as methylene blue (MB), to boost the electrochemical signal and enable quick monitoring of NPY levels in real time. To find NPY in synthetic Cerebrospinal Fluid (aCSF), real-time methods including square wave voltammetry (SWV) and cyclic voltammetry were investigated. We were able to determine the concentration of NPY in aCSF (pH = 7.4) since MB produced a distinctive signal in both procedures. As the NPY molecules interacted with the aptamer, the MB electrochemical signal was altered, resulting in a "signal-off" sensor. With the aid of these findings, we were able to create a calibration curve that will serve as the foundation for further Fast Scan Cyclic Voltammetry (FSCV) experiments that will improve the temporal and spatial resolution of our studies. Recent studies have been directed towards the testing of the selectivity by measuring different neuropeptides and their selectivity towards the aptamer-modified microelectrodes.

AFM and Electrochemical Analysis of Different Biomolecules Using Npy-Specific Aptamer Modified Electrodes

Neurotransmitters and neuropeptides are chemical signals in the brain that produce responses or functions throughout the organism. Measurements of neurotransmitters are important to understand some mechanisms of how they are released off the cell. Different biomolecules can be measured with gold (Au) electrodes because it is a ductile and malleable metal that can detect small changes and can be easily modified. In this work, we use Neuropeptide Y (NPY) specific aptamer to modify the electrodes to take advantage of the binding with NPY molecules that produce conformational changes. We also study Dopamine (DA) and Norepinephrine (NE) because they corelease with NPY and we can monitor the electrochemical difference between these biomolecules. Those modifications and detection can be monitored using Electrochemical Impedance Spectroscopy (EIS) to understand the adsorption properties of molecules that stick to the surface of the electrode and Atomic Force Microscopy (AFM) to measure the topography of the electrodes before and after the aptamer modification. Electrochemical results showed that the capacitance of the Au electrode decreases at higher concentrations of NPY. AFM results showed small changes on the surface of the Au electrodes with the different modifications due to the roughness of the surface. The results obtained give us a better understanding of the use of these techniques for the monitoring of biomolecules.

Neuropeptide Y Detection Using an Aptamer-Modifed Microelectrode Together with Methylene Blue As a Redox Probe

Neuroscience research has been growing fast over the last few years. Particularly the knowledge about neurotransmitters has increased over the past 50 years, impacting the understanding of many neurological disorders, including depression, schizophrenia, Parkinson's disease, and Alzheimer's disease. Still, there is a lack of knowledge about neuropeptides' liberation and action, and most of their function is assumed by indirect measurements. Neuropeptides are classified as non-electroactive molecules, making them difficult to track; consequently, the design of an analytical technique for their measurements is imperative. Neuropeptide Y (NPY) is the most abundant neuropeptide in the brain. It is associated with a wide range of biological processes and conditions, including depression, anxiety, obesity, alcoholism, mood changes, feeding behavior, and post-traumatic stress disorder (PTSD), among others. Currently, there is no method for NPY measurement in high temporal and spatial resolution in the brain. Therefore, we proposed the design of a biological sensor to understand the mechanism in which NPY is involved. This research is focused on electrochemical methods to detect and measure NPY based on an affinity-mediated strategy. An aptamer, a short single-stranded DNA with high affinity by NPY, was attached to a Pt surface of a microelectrode, taking advantage of the affinity between Pt and a thiol group in the aptamer structure. Then, to amplify the electrochemical signal, a redox molecule such as methylene blue (MB) was conjugated to the aptamer to allow rapid measurements of NPY levels in real-time. Real-time techniques such as cyclic voltammetry and square wave voltammetry (SWV) were explored to detect NPY in artificial Cerebrospinal Fluid (aCSF). Due to MB having a characteristic signal in both techniques, we successfully measured NPY concentration in aCSF (pH = 7.4). A change in current was observed as the NPY molecules interacted with the aptamer affecting the MB electrochemical signal and producing a "signal-off" sensor. These results allow us to obtain a calibration curve that will be used as an initial platform to perform Fast Scan Cyclic Voltammetry (FSCV) measurements to increase the time resolution in our measurements.

Clinical Investigation of French Maritime Pine Bark Extract on Attention-Deficit Hyperactivity Disorder as compared to Methylphenidate and Placebo: Part 2: Oxidative Stress and Immunological Modulation

To evaluate the effect of French Maritime Pine Bark Extract (PBE; Pycnogenol®) on immune, oxidative stress and neurochemical biomarkers in paediatric Attention-Deficit Hyperactivity Disorder (ADHD) as compared to methylphenidate (MPH) and placebo. Paediatric ADHD patients (n = 88, 70 % male, mean age 10.1 years) were randomised (placebo (n = 30), PBE (n = 32) and MPH (n = 26)) receiving 20 mg/day if < 30 kg or 40 mg/day if ≥ 30 kg PBE, or 20 mg/day if < 30 kg or 30 mg/day if ≥ 30 kg MPH for 10 weeks. In the oxidative stress pathway, catalase (CAT) activity was nominally significant different in the PBE group with a p-value of 0.025 whereas the immunity biomarkers IgA and IgG2 were nominally significant different after MPH treatment with a p-value of 0.028 and 0.017 respectively, compared to baseline. Serum Neuropeptide Y (NPY) levels and weight were significantly lower after 10-weeks MPH. Loss of appetite and weight loss was observed for MPH, whereas no differences in NPY concentrations and a significant weight gain, which is to be an expected physiological process in this age group, was noticed for PBE. Firm evidence that PBE increases antioxidant levels, reduces oxidative damage and improves immune status in general as compared to placebo or MPH could not be obtained.

Neuropeptide Y Antagonizes Development of Pulmonary Fibrosis through IL-1β Inhibition.

Neuropeptide Y (NPY), a 36 amino acid residue polypeptide distributed throughout the nervous system, acts on various immune cells in many organs, including the respiratory system. However, little is known about its role in the pathogenesis of pulmonary fibrosis. This study was performed to determine the effects of NPY on pulmonary fibrosis. NPY-deficient and wild-type mice were intratracheally administered bleomycin. Inflammatory cells, cytokine concentrations, and morphological morphometry of the lungs were analyzed. Serum NPY concentrations were also measured in patients with idiopathic pulmonary fibrosis and healthy control subjects. NPY-deficient mice exhibited significantly enhanced pulmonary fibrosis and higher IL-1β concentrations in the lungs compared with wild-type mice. Exogenous NPY treatment suppressed the development of bleomycin-induced lung fibrosis and decreased IL-1β concentrations in the lungs. Moreover, IL-1β neutralization in NPY-deficient mice attenuated the fibrotic changes. NPY decreased IL-1β release, and Y1 receptor antagonists inhibited IL-1β release and induced epithelial-mesenchymal transition in human alveolar epithelial cells. Patients with idiopathic pulmonary fibrosis had lower NPY and greater IL-1β concentrations in the serums compared with healthy control subjects. NPY expression was mainly observed around bronchial epithelial cells in human idiopathic pulmonary fibrosis lungs. These data suggest that NPY plays aprotective role against pulmonary fibrosis by suppressing IL-1β release, and manipulating the NPY-Y1 receptor axis could be a potential therapeutic strategy for delaying disease progression.

Pyrroloquinoline Quinone Regulates Enteric Neurochemical Plasticity of Weaned Rats Challenged With Lipopolysaccharide.

The enteric nervous system (ENS) is important for the intestinal barrier to defend and regulate inflammation in the intestine. The aim of this study was to investigate the effect of pyrroloquinoline quinone (PQQ) on regulating neuropeptide secretion by ENS neurons of rats challenged with lipopolysaccharide (LPS) to create enteritis. Thirty Sprague Dawley rats were divided into five groups, namely, basal (CTRL), basal plus LPS challenge (LPS), basal with 2.5 mg/kg b.w./day of PQQ plus challenge with LPS (PQQ 2.5), basal with 5.0 mg/kg b.w./day PQQ plus challenge with LPS (PQQ 5), and basal with 10.0 mg/kg b.w./day PQQ plus challenge with LPS (PQQ 10). After treatment with basal diet or PQQ for 14 days, rats were challenged with LPS except for the CTRL group. Rats were euthanized 6 h after the LPS challenge. Rats showed an increased average daily gain in PQQ treatment groups (P < 0.05). Compared with the LPS group, PQQ 5 and PQQ 10 rats showed increased villus height and villus height/crypt depth of jejunum (P < 0.05). In PQQ treatment groups, concentrations of IL-1β and TNF-α in serum and intestine of rats were decreased, and IL-10 concentration was increased in serum compared with the LPS group (P < 0.05). Compared with the LPS group, the concentration of neuropeptide Y (NPY), nerve growth factor (NGF), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), and brain-derived neurotropic factor (BDNF) in serum were decreased in PQQ treatment groups (P < 0.05). Compared with the LPS group, ileal mRNA levels of BDNF, NPY, and NGF were decreased in PQQ treatment groups (P < 0.05). Jejunal concentrations of SP, CGRP, VIP, BDNF, NPY, and NGF were decreased in PQQ treatment groups compared with the LPS group (P < 0.05). Compared with the LPS group, phosphor-protein kinase B (p-Akt)/Akt levels in jejunum and colon were decreased in PQQ treatment groups (P < 0.05). In conclusion, daily treatment with PQQ improved daily gain, jejunal morphology, immune responses. PQQ-regulated enteric neurochemical plasticity of ENS via the Akt signaling pathway of weaned rats suffering from enteritis.