Gastrodin alleviates NTG-induced migraine-like pain via inhibiting succinate/HIF-1α/TRPM2 signaling pathway in trigeminal ganglion.

BACKGROUND: Increasing evidence highlights the involvement of metabolic disorder and calcium influx mediated by transient receptor potential channels in migraine; however, the relationship between these factors in the pathophysiology of migraine remains unknown. Gastrodin is the major component of the traditional Chinese medicine Tianma, which is extensively used in migraine therapy. PURPOSE: Our work aimed to explore the analgesic action of gastrodin and its regulatory mechanisms from a metabolic perspective. METHODS/RESULTS: After being treated with gastrodin, the mice were given nitroglycerin (NTG) to induce migraine. Gastrodin treatment significantly raised the threshold of sensitivity in response to both mechanical and thermal stimulus evidenced by von Frey and hot plate tests, respectively, and decreased total contact numbers in orofacial operant behavioral assessment. We found that the expression of transient receptor potential melastatin 2 (TRPM2) channel was increased in the trigeminal ganglion (TG) of NTG-induced mice, resulting in a sustained Ca2+ influx to trigger migraine pain. The content of succinate, a metabolic biomarker, was elevated in blood samples of migraineurs, as well as in the serum and TG tissue from NTG-induced migraine mice. Calcium imaging assay indicated that succinate insult elevated TRPM2-mediated calcium flux signal in TG neurons. Mechanistically, accumulated succinate upregulated hypoxia inducible factor-1α (HIF-1α) expression and promoted its translocation into nucleus, where HIF-1α enhanced TRPM2 expression through transcriptional induction in TG neurons, evidenced by luciferase reporter measurement. Gastrodin treatment inhibited TRPM2 expression and TRPM2-dependent Ca2+ influx by attenuating succinate accumulation and downstream HIF-1α signaling, and thereby exhibited analgesic effect. CONCLUSION: This work revealed that succinate was a critical metabolic signaling molecule and the key mediator of migraine pain through triggering TRPM2-mediated calcium overload. Gastrodin alleviated NTG-induced migraine-like pain via inhibiting succinate/HIF-1α/TRPM2 signaling pathway in TG neurons. These findings uncovered the anti-migraine effect of gastrodin and its regulatory mechanisms from a metabolic perspective and provided a novel theoretical basis for the analgesic action of gastrodin.

Normalization of hemoglobin-based oxygen carrier-201 induced vasoconstriction: targeting nitric oxide and endothelin.

Hemoglobin-based oxygen carrier (HBOC)-201 is a cell-free modified hemoglobin solution potentially facilitating oxygen uptake and delivery in cardiovascular disorders and hemorrhagic shock. Clinical use has been hampered by vasoconstriction in the systemic and pulmonary beds. Therefore, we aimed to 1) determine the possibility of counteracting HBOC-201-induced pressor effects with either adenosine (ADO) or nitroglycerin (NTG); 2) assess the potential roles of nitric oxide (NO) scavenging, reactive oxygen species (ROS), and endothelin (ET) in mediating the observed vasoconstriction; and 3) compare these effects in resting and exercising swine. Chronically instrumented swine were studied at rest and during exercise after administration of HBOC-201 alone or in combination with ADO. The role of NO was assessed by supplementation with NTG or administration of the eNOS inhibitor Nω-nitro-l-arginine. Alternative vasoactive pathways were investigated via intravenous administration of the ETA/ETB receptor blocker tezosentan or a mixture of ROS scavengers. The systemic and to a lesser extent the pulmonary pressor effects of HBOC-201 could be counteracted by ADO; however, dosage titration was very important to avoid systemic hypotension. Similarly, supplementation of NO with NTG negated the pressor effects but also required titration of the dose. The pressor response to HBOC-201 was reduced after eNOS inhibition and abolished by simultaneous ETA/ETB receptor blockade, while ROS scavenging had no effect. In conclusion, the pressor response to HBOC-201 is mediated by vasoconstriction due to NO scavenging and production of ET. Further research should explore the effect of longer-acting ET receptor blockers to counteract the side effect of hemoglobin-based oxygen carriers.NEW & NOTEWORTHY Hemoglobin-based oxygen carrier (HBOC)-201 can disrupt hemodynamic homeostasis, mimicking some aspects of endothelial dysfunction, resulting in elevated systemic and pulmonary blood pressures. HBOC-201-induced vasoconstriction is mediated by scavenging nitric oxide (NO) and by upregulating endothelin (ET) production. Pressor effects can be prevented by adjuvant treatment with NO donors or direct vasodilators, such as nitroglycerin or adenosine, but dosages must be carefully monitored to avoid hypotension. However, hemodynamic normalization is more easily achieved via administration of an ET receptor blocker.

[Progression of the mechanism study on experimental migraine treated with acupuncture in rat model].

In the paper, by taking acupuncture and migraine as the key words to retrieve CNKI and PubMed database, the literature analysis was done on the mechanism study on experimental migraine treated with acupuncture in rat model. The results showed that acupuncture mechanism study focused on the regulation and control of the relevant neurotransmitters/neuromodulators of migraine, such as calcitonin gene-related peptide (CGRP), serotonin (5-HT), nitric oxide (NO), etc. Moreover, in the paper, the review had been done on the neurotransmitters/neuromodulators involved in the study.

A restoration-promoting integrated floating bed and its experimental performance in eutrophication remediation.

Numerous studies on eutrophication remediation have mainly focused on purifying water first, then restoring submerged macrophytes. A restoration-promoting integrated floating bed (RPIFB) was designed to combine the processes of water purification and macrophyte restoration simultaneously. Two outdoor experiments were conducted to evaluate the ecological functions of the RPIFB. Trial 1 was conducted to compare the eutrophication purification among floating bed, gradual-submerging bed (GSB) and RPIFB technologies. The results illustrated that RPIFB has the best purification capacity. Removal efficiencies of RPIFB for TN, TP, NH(+)4-N, NO(-)3-N, CODCr, Chlorophyll-a and turbidity were 74.45%, 98.31%, 74.71%, 88.81%, 71.42%, 90.17% and 85%, respectively. In trial 2, influences of depth of GSB and photic area in RPIFB on biota were investigated. When the depth of GSB decreased and the photic area of RPIFB grew, the height of Potamogeton crispus Linn. increased, but the biomass of Canna indica Linn. was reduced. The mortalities of Misgurnus anguillicaudatus and Bellamya aeruginosa in each group were all less than 7%. All results indicated that when the RPIFB was embedded into the eutrophic water, the regime shift from phytoplankton-dominated to macrophyte-dominated state could be promoted. Thus, the RPIFB is a promising remediation technology for eutrophication and submerged macrophyte restoration.

Identification of nitroglycerin-induced cysteine modifications of pro-matrix metalloproteinase-9.

Nitroglycerin (NTG), an important cardiovascular agent, has been shown recently to activate matrix metalloproteinase-9 (MMP-9) in biological systems, possibly leading to destabilization of atherosclerotic plaques. The chemical mechanism for this activation, particularly on the cysteine switch of the pro-form of MMP-9 (proMMP-9), has not been investigated and was examined here using nano-flow liquid chromatography coupled to mass spectrometry. In order to obtain high sequence coverage, two orthogonal enzymes (trypsin and GluC) were employed to digest the protein in parallel. Two complementary activation methods, collision-induced dissociation (CID) and electron-transfer dissociation (ETD), were employed for the identification of various modifications. A high-resolution Orbitrap analyzer was used to enable confident identification. Incubation of NTG with proMMP-9 resulted in the formation of an unstable thionitrate intermediate and oxidation of the cysteine switch to sulfinic and irreversible sulfonic acid derivatives. The unstable thionitrate modification was confirmed by both CID and ETD in the proteolytic peptides produced by both trypsin and GluC. Incubation of proMMP-9 with diethylenetriamine NONOate (a nitric oxide donor) led to sulfonic acid formation, but no observable sulfinic acid modification. Extensive tyrosine nitration by NTG was observed at Tyr-262, in close proximity to an oxidized Cys-256 of proMMP-9. The intramolecular interaction between these two residues toward NTG-induced oxidation was examined using a synthesized peptide representing the sequence in this domain, PWCSTTANYDTDDR, and the modification status was compared against an analog in which Cys was substituted by Ala. We observed a thionitrate product, extensive Cys oxidative modifications and enhanced tyrosine nitration with the Cys peptide but not with the Ala analog. Our results indicated that neighboring Cys and Tyr residues can facilitate each other's oxidation in the presence of NTG.

Evaluation of anti-migraine potential of Areca catechu to prevent nitroglycerin-induced delayed inflammation in rat meninges: possible involvement of NOS inhibition.

ETHNOPHARMACOLOGICAL RELEVANCE: Areca catechu nut extract is a popular folk remedy for the treatment of migraine in Kerala and Tamil Nadu states of India. AIM OF THE STUDY: In order to prove the claimed utilization of plant, the effect of hydroalcoholic extract of Areca catechu nut (ANE) was investigated in nitroglycerine induced inflammation in rat meninges. In these models infusion of nitric oxide donor glyceryl trinitrate (GTN) produces augmented plasma protein extravasation (PPE) in dura mater, provides an important substrate for the development of migraine in rats. MATERIALS AND METHODS: The effect on plasma protein extravasation was assessed in both the models of intravenous and topical GTN application following oral administration of ANE (250 mg/kg and 500 mg/kg) in both curative and preventive treatment and compared with that of control positive. The l-NAME (15 mg/kg, i.v.) was used as reference standard. Plasma protein extravasation was measured using fluorescein as marker and was measured using a Perkin-Elmer LS-30 luminescence spectrometer. RESULTS: Expression of iNOS in the spleen after intravenous injection produced PPE into the dura mater in control positive group was significantly (P<0.01) reduced to 1.553±0.02499 and 1.398±0.01887 by preventive treatment with ANE at the dose of 250 and 500 mg/kg, orally, respectively. The extravasation produced by topical GTN due to expression of iNOS in dural macrophages was also reduced to 1.555±0.03384 and 1.425±0.01204 by preventive treatment with ANE at the dose of 250 and 500 mg/kg, orally, respectively. While ANE do not showed any significant results in curative treatment in both the models of i.v. and topical GTN application. CONCLUSION: These findings collectively indicate that the extract exhibited significant inhibition of iNOS, which may be the probable mechanism for its anti-migraine activity, providing evidence, at least in part, for its folkloric use.

Reversal of mitochondrial dysfunction by coenzyme Q10 supplement improves endothelial function in patients with ischaemic left ventricular systolic dysfunction: a randomized controlled trial.

AIMS: Coronary artery disease (CAD) is associated with endothelial dysfunction and mitochondrial dysfunction (MD). The aim of this study was to investigate whether co-enzyme Q10 (CoQ) supplementation, which is an obligatory coenzyme in the mitochondrial respiratory transport chain, can reverse MD and improve endothelial function in patients with ischaemic left ventricular systolic dysfunction (LVSD). METHODS AND RESULTS: We performed a randomized, double-blind, placebo-controlled trial to determine the effects of CoQ supplement (300 mg/day, n=28) vs. placebo (controls, n=28) for 8 weeks on brachial flow-mediated dilation (FMD) in patients with ischaemic LVSD(left ventricular ejection fraction <45%). Mitochondrial function was determined by plasma lactate/pyruvate ratio (LP ratio). After 8 weeks, CoQ-treated patients had significant increases in plasma CoQ concentration (treatment effect 2.20 µg/mL, P<0.001) and FMD (treatment effect 1.51%, P=0.03); and decrease in LP ratio (treatment effect -2.46, P=0.03) compared with controls. However, CoQ treatment did not alter nitroglycerin-mediated dilation, blood pressure, blood levels of fasting glucose, haemoglobin A1c, lipid profile, high-sensitivity C-reactive protein and oxidative stress as determined by serum superoxide dismutase and 8-isoprostane (all P>0.05). Furthermore, the reduction in LP ratio significantly correlated with improvement in FMD (r=-0.29, P=0.047). CONCLUSION: In patients with ischaemic LVSD, 8 weeks supplement of CoQ improved mitochondrial function and FMD; and the improvement of FMD correlated with the change in mitochondrial function, suggesting that CoQ improved endothelial function via reversal of mitochondrial dysfunction in patients with ischaemic LVSD.

Nitroglycerin enhances proliferation and osteoblastic differentiation in human mesenchymal stem cells via nitric oxide pathway.

AIM: To investigate the effect of nitroglycerin (NTG) on cell proliferation and osteoblastic differentiation of human bone marrow-derived mesenchymal stem cells (HBMSC) and its mechanisms. METHODS: Primary HBMSC were cultured in osteogenic differentiation medium consisting of phenol red-free alpha-minimum essential media plus 10% fetal bovine serum (dextran-coated charcoal stripped) supplemented with 10 nmol/L dexamethasone, 50 mg/L ascorbic acid, and 10 mmol/L beta-glycerophosphate for inducing osteoblastic differentiation. The cells were treated with NTG (0.1-10 micromol/L) alone or concurrent incubation with different nitric oxide synthase (NOS) inhibitors. Nitric oxide (NO) production was measured by using a commercial NO kit. Cell proliferation was measured by 5-bromodeoxyuridine (BrdU) incorporation. The osteoblastic differentiation of HBMSC culture was evaluated by measuring cellular alkaline phosphatase (ALP) activity and calcium deposition, as well as osteoblastic markers by real-time RT-PCR. RESULTS: The treatment of HBMSC with NTG (0.1-10 micromol/L) led to a dose-dependent increase of NO production in the conditional medium. The release of NO by NTG resulted in increased cell proliferation and osteoblastic differentiation of HBMSC, as evidenced by the increment of the BrdU incorporation, the induction of ALP activity in the early stage, and the calcium deposition in the latter stage. The increment of NO production was also correlated with the upregulation of osteoblastic markers in HBMSC cultures. However, the stimulatory effect of NTG (10 micromol/L) could not be abolished by either N(G ) -nitro-L-arginine methyl ester, an antagonist of endothelial NOS, or 1400W, a selective blocker of inducible NOS activity. CONCLUSION: NTG stimulates cell proliferation and osteoblastic differentiation of HBMSC through a direct release of NO, which is independent on intracellular NOS activity.

Rationale for using nitric oxide donor therapy for prevention of bone loss and treatment of osteoporosis in humans.

Nitric oxide (NO) is a ubiquitous molecule involved in most cellular functions. While osteocytes communicate between bone cells, diffusible small molecules-H(+) and NO-are involved in short-term regulation of bone metabolism. Studies conducted over the past two decades have demonstrated the regulatory role of NO in bone metabolism. Circulating NO products are significantly lower in postmenopausal women, and estrogen supplementation restores this. Skeletal beneficial effects of estrogen are abolished with NO-synthase enzyme inhibitors, suggesting some estrogenic skeletal effects are mediated through NO/cGMP pathway. Since estrogen/hormone replacement therapy (HRT) has potential adverse effects, supplementing NO directly is sensible. NO is also involved with other cellular functions, such as isoprenylation of the Rho GTPase that stimulates Rho-PK (the functioning Rho-PK in turn inactivates something that would otherwise turn on the BMP-2/Cbfa1-Runx-2 cycle), and likely to be the final common pathway of other agents including statins. The first human study using nitroglycerine in the prevention of oophorectomy-induced bone loss demonstrated an equivalent efficacy to estrogen in the prevention of bone loss. A randomized NIH-funded NOVEL clinical study is currently assessing the effectiveness of topically administered nitroglycerine in the prevention of postmenopausal bone loss. If efficacy of nitroglycerine is confirmed, it may become a highly cost-effective and safe alternative therapy to treat osteoporosis. Nitroglycerine has beneficial effects in multiple systems, especially the cardiovascular system. If results of this study confirm our hypothesis, it is plausible that nitroglycerine therapy may supplant estrogen replacement and SERMs in preventing and treating postmenopausal osteoporosis.

Tetrahydrobiopterin improves endothelium-dependent vasodilation in nitroglycerin-tolerant rats.

Tolerance to nitroglycerin is caused by a nitroglycerin-mediated increase in vascular superoxide anion production. Administration of tetrahydrobiopterin (co-factor for endogenous nitric oxide (NO) formation) may potentially influence nitroglycerin tolerance in at least two different ways. Firstly, tetrahydrobiopterin may act as a scavenger of the nitroglycerin-mediated production of superoxide anions. Secondly, tetrahydrobiopterin may protect endothelial NO synthesis from the deleterious effects of increased oxidative stress. This study investigates whether in vivo nitroglycerin tolerance is affected by tetrahydrobiopterin supplementation and assesses the in vivo role of tetrahydrobiopterin in endogenous NO-mediated vasodilation in normal and nitroglycerin-tolerant rats. The results show that tetrahydrobiopterin does not affect nitroglycerin-derived, NO-mediated vasodilation, but reduces baseline mean arterial blood pressure (by 8 mm Hg, P<0.05) and normalizes endothelium-dependent responses to N(G)-monomethyl-L-arginine (L-NMMA) (from 7+/-1 to 22+/-4 mm Hg, P<0.05) in nitroglycerin-tolerant rats. It is concluded that altered bioavailability of tetrahydrobiopterin is involved in the pathophysiology of endothelial dysfunction seen in nitroglycerin tolerance.

Platelet inhibitory effect of nitroglycerin in platelet-rich plasma: relevance of glutathione-s-transferases in plasma.

BACKGROUND: Nitroglycerin (NTG) is believed to exert its platelet inhibitory effect via its biotransformation to nitric oxide (NO). We examined the relevance of glutathione-s-transferases (GST) in plasma in the conversion of NTG to NO and the platelet inhibitory effect of NTG. METHODS AND RESULTS: Nitroglycerin (1-100 micrograms/mL) was incubated with human platelet-rich plasma (PRP) for 10-60 minutes. Nitroglycerin caused a concentration-dependent inhibition of platelet aggregation in PRP with IC50 approximately 50 micrograms/mL. NTG also enhanced nitrite levels in PRP and stimulated cyclic GMP accumulation in platelets. In contrast, when NTG was incubated with washed platelets (WP) in concentrations as high as 100 micrograms/mL, there was no inhibition of platelet aggregation, formation of nitrite, or accumulation of cGMP. However, treatment of WP suspension with authentic NO exhibited diminished platelet aggregation, suggesting that NTG delivers NO in plasma that subsequently inhibits platelet aggregation. In keeping with this concept, the aggregation inhibitory effect of NTG in PRP was blocked by oxyhemoglobin. The platelet aggregation inhibition by NTG was potentiated by propylthiouracil (600 micrograms/mL), a GST inducer, and antagonized by ketoprofen (100 micrograms/mL), a GST inhibitor. Direct measurement indeed showed significant GST activity in plasma (24 +/- 3 mU/mL). CONCLUSIONS: We suggest that NTG inhibits platelet aggregation in PRP by its biotransformation to NO in plasma. The presence of GST, and perhaps other cofactors, in plasma is relevant in the platelet inhibitory effects of NTG in PRP.