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Respiratory Research Jan 2012Acute respiratory disorders may lead to sustained alveolar hypoxia with hypercapnia resulting in impaired pulmonary gas exchange. Hypoxic pulmonary vasoconstriction...
BACKGROUND
Acute respiratory disorders may lead to sustained alveolar hypoxia with hypercapnia resulting in impaired pulmonary gas exchange. Hypoxic pulmonary vasoconstriction (HPV) optimizes gas exchange during local acute (0-30 min), as well as sustained (> 30 min) hypoxia by matching blood perfusion to alveolar ventilation. Hypercapnia with acidosis improves pulmonary gas exchange in repetitive conditions of acute hypoxia by potentiating HPV and preventing pulmonary endothelial dysfunction. This study investigated, if the beneficial effects of hypercapnia with acidosis are preserved during sustained hypoxia as it occurs, e.g in permissive hypercapnic ventilation in intensive care units. Furthermore, the effects of NO synthase inhibitors under such conditions were examined.
METHOD
We employed isolated perfused and ventilated rabbit lungs to determine the influence of hypercapnia with or without acidosis (pH corrected with sodium bicarbonate), and inhibitors of endothelial as well as inducible NO synthase on acute or sustained HPV (180 min) and endothelial permeability.
RESULTS
In hypercapnic acidosis, HPV was intensified in sustained hypoxia, in contrast to hypercapnia without acidosis when HPV was amplified during both phases. L-NG-Nitroarginine (L-NNA), a non-selective NO synthase inhibitor, enhanced acute as well as sustained HPV under all conditions, however, the amplification of sustained HPV induced by hypercapnia with or without acidosis compared to normocapnia disappeared. In contrast 1400 W, a selective inhibitor of inducible NO synthase (iNOS), decreased HPV in normocapnia and hypercapnia without acidosis at late time points of sustained HPV and selectively reversed the amplification of sustained HPV during hypercapnia without acidosis. Hypoxic hypercapnia without acidosis increased capillary filtration coefficient (Kfc). This increase disappeared after administration of 1400 W.
CONCLUSION
Hypercapnia with and without acidosis increased HPV during conditions of sustained hypoxia. The increase of sustained HPV and endothelial permeability in hypoxic hypercapnia without acidosis was iNOS dependent.
Topics: Acidosis; Animals; Enzyme Inhibitors; Hypercapnia; Hypoxia; Imines; Lung; Male; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Nitroarginine; Pulmonary Circulation; Rabbits; Sodium Bicarbonate; Vasoconstriction
PubMed: 22292558
DOI: 10.1186/1465-9921-13-7 -
Poultry Science May 2012The aim of the present study was to clarify the responsiveness of the chicken basilar artery to 5-hydroxytryptamine (5-HT) and acetylcholine (ACh) and to characterize...
The aim of the present study was to clarify the responsiveness of the chicken basilar artery to 5-hydroxytryptamine (5-HT) and acetylcholine (ACh) and to characterize the related receptor subtypes in vitro. Basilar arteries were obtained from freshly slaughtered broiler chickens. The 5-HT induced concentration-dependent contraction of the arteries. The concentration-response curves for 5-HT were shifted 30-fold to the right by methiothepin (a 5-HT(1) and 5-HT(2) receptor antagonist) and 3-fold to the right by ketanserin (a 5-HT(2) receptor antagonist). In the presence of ketanserin, the concentration-response curve for 5-HT was shifted 10-fold to the right by methiothepin. The pA(2) value for methiothepin was 8.26. The ACh induced concentration-dependent relaxation under conditions of precontraction by 5-HT. The concentration-response curve for ACh was shifted to the right by atropine [a nonselective muscarinic (M) receptor antagonist] and hexahydro-sila-difenidol hydrochloride, a p-fluoroanalog (pFHHSiD, an M(3) receptor antagonist), but not by pirenzepine (an M(1) receptor antagonist) or methoctramine (an M(2) receptor antagonist). The pA(2) value for pFHHSiD was 7.55. Nω-Nitro-l-arginine (a nitric oxide synthase inhibitor) inhibited ACh-induced relaxation by approximately 50%. These results suggest that 5-HT induces contraction via activation of 5-HT(1) and 5-HT(2) receptors and that ACh induces relaxation via activation of the M(3) receptor. The 5-HT(1) receptor might play a dominant role in 5-HT-induced contraction. One of the factors involved in ACh-induced relaxation is probably nitric oxide released from endothelial cells.
Topics: Acetylcholine; Animals; Basilar Artery; Chickens; Enzyme Inhibitors; Female; Ketanserin; Male; Methiothepin; Nitroarginine; Parasympatholytics; Serotonin; Serotonin Antagonists; Vasoconstrictor Agents; Vasodilator Agents
PubMed: 22499874
DOI: 10.3382/ps.2011-01945 -
Nan Fang Yi Ke Da Xue Xue Bao = Journal... Jan 2017To study the effect of methamphetamine (METH) exposure on S-nitrosylation of protein disulphide isomerase and the neurotoxicity of METH in PC12 cells.
OBJECTIVE
To study the effect of methamphetamine (METH) exposure on S-nitrosylation of protein disulphide isomerase and the neurotoxicity of METH in PC12 cells.
METHODS
PC12 cells were exposed to different concentrations of METH, and the cell viability was assessed using the cell-counting kit-8. PC12 cells exposed to METH in the presence of the NOS inhibitor N-nitro-L-arginine (L-NNA) were examined for cell viability and S-nitrosylation of protein disulphide isomerase using the biotin-switch method, and the changes in cell morphology were examined with HE staining.
RESULTS
METH exposure obviously decreased the cell viability and increased S-nitrosylation of protein disulphide isomerase, and the effect of METH was obviously inhibited by L-NNA treatment.
CONCLUSION
METH can cause obvious neurotoxicity and promote S-nitrosylation of protein disulphide isomerase in PC12 cells.
Topics: Animals; Cell Count; Cell Shape; Cell Survival; Enzyme Inhibitors; Methamphetamine; Nitric Oxide Synthase; Nitroarginine; PC12 Cells; Protein Disulfide-Isomerases; Rats
PubMed: 28109106
DOI: 10.3969/j.issn.1673-4254.2017.01.17 -
American Journal of Physiology.... Jul 2004To compare electrical field stimulation (EFS) with nicotine in the stimulation of excitatory and inhibitory enteric motoneurons (EMN) in the human esophagus, circular...
To compare electrical field stimulation (EFS) with nicotine in the stimulation of excitatory and inhibitory enteric motoneurons (EMN) in the human esophagus, circular lower esophageal sphincter (LES), and circular and longitudinal esophageal body (EB) strips from 20 humans were studied in organ baths. Responses to EFS or nicotine (100 microM) were compared in basal conditions, after N(G)-nitro-l-arginine (l-NNA; 100 microM), and after l-NNA and apamin (1 microM). LES strips developed myogenic tone enhanced by TTX (5 microM) or l-NNA. EFS-LES relaxation was abolished by TTX, unaffected by hexamethonium (100 microM), and enhanced by atropine (3 microM). Nicotine-LES relaxation was higher than EFS relaxation, reduced by TTX or atropine, and blocked by hexamethonium. After l-NNA, EFS elicited a strong cholinergic contraction in circular LES and EB, and nicotine elicited a small relaxation in LES and no contractile effect in EB. After l-NNA and apamin, EFS elicited a strong cholinergic contraction in LES and EB, and nicotine elicited a weak contraction amounting to 6.64 +/- 3.19 and 9.20 +/- 5.51% of that induced by EFS. EFS elicited a contraction in longitudinal strips; after l-NNA and apamin, nicotine did not induce any response. Inhibitory EMN tonically inhibit myogenic LES tone and are efficiently stimulated both by EFS and nicotinic acetylcholine receptors (nAChRs) located in somatodendritic regions and nerve terminals, releasing nitric oxide and an apamin-sensitive neurotransmitter. In contrast, although esophageal excitatory EMN are efficiently stimulated by EFS, their stimulation through nAChRs is difficult and causes weak responses, suggesting the participation of nonnicotinic mechanisms in neurotransmission to excitatory EMN in human esophagus.
Topics: Apamin; Cholinergic Agents; Electric Stimulation; Enzyme Inhibitors; Esophagogastric Junction; Esophagus; Female; Humans; In Vitro Techniques; Male; Middle Aged; Motor Neurons; Muscle Contraction; Muscle Tonus; Muscle, Smooth; Neural Inhibition; Nicotine; Nitroarginine; Tetrodotoxin
PubMed: 15016616
DOI: 10.1152/ajpgi.00534.2003 -
American Journal of Physiology.... Mar 2004Nitric oxide (NO) and NO synthase (NOS) play controversial roles in pancreatic secretion. NOS inhibition reduces CCK-stimulated in vivo pancreatic secretion, but it is...
Nitric oxide (NO) and NO synthase (NOS) play controversial roles in pancreatic secretion. NOS inhibition reduces CCK-stimulated in vivo pancreatic secretion, but it is unclear which NOS isoform is responsible, because NOS inhibitors lack specificity and three NOS isoforms exist: neuronal (nNOS), endothelial (eNOS), and inducible (iNOS). Mice having individual NOS gene deletions were used to clarify the NOS species and cellular interactions influencing pancreatic secretion. In vivo secretion was performed in anesthetized mice by collecting extraduodenal pancreatic duct juice and measuring protein output. Nonselective NOS blockade was induced with N(omega)-nitro-L-arginine (L-NNA; 10 mg/kg). In vivo pancreatic secretion was maximal at 160 pmol.kg(-1).h(-1) CCK octapeptide (CCK-8) and was reduced by NOS blockade (45%) and eNOS deletion (44%). Secretion was unaffected by iNOS deletion but was increased by nNOS deletion (91%). To determine whether the influence of NOS on secretion involved nonacinar events, in vitro CCK-8-stimulated secretion of amylase from isolated acini was studied and found to be unaltered by NOS blockade and eNOS deletion. Influence of NOS on in vivo secretion was further examined with carbachol. Protein secretion, which was maximal at 100 nmol.kg(-1).h(-1) carbachol, was reduced by NOS blockade and eNOS deletion but unaffected by nNOS deletion. NOS blockade by L-NNA had no effect on carbachol-stimulated amylase secretion in vitro. Thus constitutive NOS isoforms can exert opposite effects on in vivo pancreatic secretion. eNOS likely plays a dominant role, because eNOS deletion mimics NOS blockade by inhibiting CCK-8 and carbachol-stimulated secretion, whereas nNOS deletion augments CCK-8 but not carbachol-stimulated secretion.
Topics: Amylases; Animals; Carbachol; Dose-Response Relationship, Drug; Enzyme Inhibitors; Isoenzymes; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Nitroarginine; Pancreas; Proteins; Sincalide; Stimulation, Chemical
PubMed: 14551061
DOI: 10.1152/ajpgi.00368.2003 -
British Journal of Pharmacology Feb 2016In the phase III clinical trial, RELAX-AHF, serelaxin caused rapid and long-lasting haemodynamic changes. However, the cellular mechanisms involved are unclear in humans.
BACKGROUND AND PURPOSE
In the phase III clinical trial, RELAX-AHF, serelaxin caused rapid and long-lasting haemodynamic changes. However, the cellular mechanisms involved are unclear in humans.
EXPERIMENTAL APPROACH
This study examined the effects of serelaxin in co-cultures of human primary endothelial cells (ECs) and smooth muscle cells (SMCs) on cAMP and cGMP signalling.
KEY RESULTS
Stimulation of HUVECs or human coronary artery endothelial cells (HCAECs) with serelaxin, concentration-dependently increased cGMP accumulation in co-cultured SMCs to a greater extent than in monocultures of either cell type. This was not observed in human umbilical artery endothelial cells (HUAECs) that do not express the relaxin receptor, RXFP1. Treatment of ECs with l-N(G) -nitro arginine (NOARG; 30 μM, 30 min) inhibited serelaxin-mediated (30 nM) cGMP accumulation in HUVECs, HCAECs and co-cultured SMCs. In HCAECs, but not HUVECs, pre-incubation with indomethacin (30 μM, 30 min) also inhibited cGMP accumulation in SMCs. Pre-incubation of SMCs with the guanylate cyclase inhibitor ODQ (1 μM, 30 min) had no effect on serelaxin-mediated (30 nM) cGMP accumulation in HUVECs and HCAECs but inhibited cGMP accumulation in SMCs. Serelaxin stimulation of HCAECs, but not HUVECs, increased cAMP accumulation concentration-dependently in SMCs. Pre-incubation of HCAECs with indomethacin, but not l-NOARG, abolished cAMP accumulation in co-cultured SMCs, suggesting involvement of prostanoids.
CONCLUSIONS AND IMPLICATIONS
In co-cultures, treatment of ECs with serelaxin caused marked cGMP accumulation in SMCs and with HCAEC also cAMP accumulation. Responses involved EC-derived NO and with HCAEC prostanoid production. Thus, serelaxin differentially modulates vascular tone in different vascular beds.
Topics: Coculture Techniques; Coronary Vessels; Cyclic AMP; Cyclic GMP; Endothelial Cells; Humans; Indomethacin; Myocytes, Smooth Muscle; Nitroarginine; Oxadiazoles; Quinoxalines; Receptors, G-Protein-Coupled; Receptors, Peptide; Recombinant Proteins; Relaxin; Signal Transduction; Umbilical Arteries; Umbilical Veins
PubMed: 26493539
DOI: 10.1111/bph.13371 -
British Journal of Pharmacology Dec 2003Increased circulating levels of adrenomedullin (ADM) cause peripheral vasodilatation and hypotension, accompanied by cardiac actions including tachycardia and increases... (Comparative Study)
Comparative Study
Increased circulating levels of adrenomedullin (ADM) cause peripheral vasodilatation and hypotension, accompanied by cardiac actions including tachycardia and increases in cardiac contractility, cardiac output, coronary conductance (CC) and coronary blood flow (CBF). It is unclear to what extent these cardiac effects are direct actions of ADM or secondary to the hypotension and altered cardiac loading. The direct cardiac actions of ADM were examined in conscious sheep previously implanted with aortic and coronary flow probes, and an indwelling left coronary artery cannula. Responses to infusion of ADM (0.5 microg kg(-1) h(-1) for 1 h) into the left coronary artery or jugular vein were compared (n=6). The effect of blockade of nitric oxide (NO) synthase with intracoronary (i.c.) N(omega)-nitro-l-arginine (l-NNA; 1.5 mg kg(-1) h(-1), infused for 2 h before and during ADM infusion, was assessed to determine whether the responses to ADM were mediated by NO (n=5). I.c. ADM caused large and sustained increases in CC (0.35+/-0.07-0.55+/-0.13 ml min(-1) mmHg-1, P<0.05) and CBF (28+/-6-42+/-9 ml min(-1), P<0.05), but had no effect on arterial pressure or indices of cardiac contractility (first differential of the upstroke of systole and peak aortic flow rate). Intravenous infusion of ADM had no effects. I.c. l-NNA, at a dose that abolished the coronary vasodilator action of acetylcholine, blocked ADM-induced coronary vasodilatation. In conclusion, ADM had a direct coronary vasodilator action that was mediated by release of endogenous NO and resulted in increased CBF. There was no evidence for a direct inotropic action of ADM.
Topics: Adrenomedullin; Animals; Coronary Vessels; Female; Infusions, Intra-Arterial; Infusions, Intravenous; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Peptides; Sheep; Time Factors; Vasodilation; Vasodilator Agents
PubMed: 14623767
DOI: 10.1038/sj.bjp.0705572 -
Reproductive Sciences (Thousand Oaks,... Jan 2010Using a rat model, we investigated the effects of circulating factors in pregnancy on cerebrovascular and systemic vascular function by comparing myogenic reactivity,...
Using a rat model, we investigated the effects of circulating factors in pregnancy on cerebrovascular and systemic vascular function by comparing myogenic reactivity, tone, and endothelial vasodilator production of the posterior cerebral artery (PCA) and mesenteric artery (MA) of nonpregnant (NP) animals perfused with nonpregnant and pregnant human plasma. Arteries from late pregnant (LP) animals were then perfused similarly to evaluate a potential adaptive effect of pregnancy on vessel function. A 3-hour exposure to pregnant plasma caused increased myogenic reactivity and tone in vessels from NP animals and produced a decreased endothelium-derived hyperpolarizing factor response in NP PCAs, findings that were not seen with MAs. The increased reactivity and tone noted in NP vessels was abolished when pregnant plasma was perfused through LP arteries, suggesting these vessels adapt during pregnancy to the vasoconstricting influence of pregnant plasma.
Topics: Adaptation, Physiological; Adult; Analysis of Variance; Angiography; Animals; Blood Pressure; Blood Transfusion; Cyclooxygenase Inhibitors; Endothelium, Vascular; Enzyme Inhibitors; Female; Humans; Indomethacin; Mesenteric Arteries; Muscle Contraction; Nitroarginine; Posterior Cerebral Artery; Pregnancy; Rats; Rats, Sprague-Dawley; Vascular Resistance; Vasoconstriction
PubMed: 19767537
DOI: 10.1177/1933719109345288 -
PloS One 2020Parkinson's disease (PD) is a common neurodegenerative disorder which is mostly sporadic but familial-linked PD (FPD) cases have also been found. The first reported gene...
S-Nitrosylation of G protein-coupled receptor kinase 6 and Casein kinase 2 alpha modulates their kinase activity toward alpha-synuclein phosphorylation in an animal model of Parkinson's disease.
Parkinson's disease (PD) is a common neurodegenerative disorder which is mostly sporadic but familial-linked PD (FPD) cases have also been found. The first reported gene mutation that linked to PD is α-synuclein (α-syn). Studies have shown that mutations, increased expression or abnormal processing of α-syn can contribute to PD, but it is believed that multiple mechanisms are involved. One of the contributing factors is post-translational modification (PTM), such as phosphorylation of α-syn at serine 129 by G-protein-coupled receptor kinases (GRKs) and casein kinase 2α (CK2α). Another known important contributing factor to PD pathogenesis is oxidative and nitrosative stress. In this study, we found that GRK6 and CK2α can be S-nitrosylated by nitric oxide (NO) both in vitro and in vivo. S-nitrosylation of GRK6 and CK2α enhanced their kinase activity towards the phosphorylation of α-syn at S129. In an A53T α-syn transgenic mouse model of PD, we found that increased GRK6 and CK2α S-nitrosylation were observed in an age dependent manner and it was associated with an increased level of pSer129 α-syn. Treatment of A53T α-syn transgenic mice with Nω-Nitro-L-arginine (L-NNA) significantly reduced the S-nitrosylation of GRK6 and CK2α in the brain. Finally, deletion of neuronal nitric oxide synthase (nNOS) in A53T α-syn transgenic mice reduced the levels of pSer129 α-syn and α-syn in an age dependent manner. Our results provide a novel mechanism of how NO through S-nitrosylation of GRK6 and CK2α can enhance the phosphorylation of pSer129 α-syn in an animal model of PD.
Topics: Age Factors; Animals; Casein Kinase II; Disease Models, Animal; G-Protein-Coupled Receptor Kinases; Gene Deletion; HEK293 Cells; Humans; Mice; Mice, Transgenic; Mutation; Nitric Oxide; Nitric Oxide Synthase Type I; Nitroarginine; Nitrosative Stress; Parkinson Disease; Phosphorylation; Serine; alpha-Synuclein
PubMed: 32343709
DOI: 10.1371/journal.pone.0232019 -
Polish Journal of Pharmacology 2001The influence of cyclooxygenase (COX) and NO synthase inhibitors on antinociceptive action of acetaminophen (ACETA) was studied in rats. ACETA increased the nociceptive...
The influence of cyclooxygenase (COX) and NO synthase inhibitors on antinociceptive action of acetaminophen (ACETA) was studied in rats. ACETA increased the nociceptive threshold for both mechanical (Randall-Selitto test) and chemical stimuli (writhing test). In both models the existence of ceiling dose of ACETA was observed. Indomethacin (IND), an inhibitor preferentially acting on COX-1, as well as nimesulide (NIM) and celecoxib (CECOX), i.e. respectively preferential and selective inhibitors of COX-2, markedly decreased the antinociceptive activity of ACETA in Randall-Selitto test. In contrast, IND increased, whereas both NIM and CECOX did not have any effect on ACETA action in writhing test. Pretreatment with LG-nitro-L-arginine (L-NO-ARG), an unspecific inhibitor of NO synthase, 7-nitroindazole (7-NI), relatively specific inhibitor of neuronal NO synthase, and L-N6(1-iminoethyl)lysine (L-NIL), relatively selective inhibitor of inducible NO synthase, significantly increased the action of the lower doses of ACETA (50 and 100 mg/kg) in writhing test, whereas it did not modify the effects of the higher doses. Similar effect of L-NO-ARG and 7-NI was observed in Randall-Selitto test, whereas L-NIL did not influence the action of ACETA. The possible involvement of COX and NO synthase systems in antinociceptive activity of ACETA is discussed.
Topics: Acetaminophen; Analgesics, Non-Narcotic; Animals; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Enzyme Inhibitors; Indazoles; Isoenzymes; Lysine; Male; Membrane Proteins; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitroarginine; Pain Threshold; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Wistar; Reaction Time; Stimulation, Chemical; Stress, Mechanical; Substrate Specificity
PubMed: 11990080
DOI: No ID Found