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1.
Chonnam Medical Journal ; : 63-71, 2018.
Article in English | WPRIM | ID: wpr-739310

ABSTRACT

Purinergic receptors play an important role in regulating gastrointestinal (GI) motility. Interstitial cells of Cajal (ICCs) are pacemaker cells that regulate GI smooth muscle activity. We studied the functional roles of external adenosine 5′-triphosphate (ATP) on pacemaker activity in cultured ICCs from mouse small intestines by using the whole-cell patch clamp technique and intracellular Ca²⁺ ([Ca²⁺]ᵢ) imaging. External ATP dose-dependently depolarized the resting membrane and produced tonic inward pacemaker currents, and these effects were antagonized by suramin, a purinergic P2 receptor antagonist. ATP-induced effects on pacemaker currents were suppressed by an external Na⁺-free solution and inhibited by the nonselective cation channel blockers, flufenamic acid and niflumic acid. The removal of external Ca²⁺ or treatment with thapsigargin (inhibitor of Ca²⁺ uptake into endoplasmic reticulum) inhibited the ATP-induced effects on pacemaker currents. Spontaneous [Ca²⁺]ᵢ oscillations were enhanced by external ATP. These results suggest that external ATP modulates pacemaker activity by activating nonselective cation channels via external Ca²⁺ influx and [Ca²⁺]ᵢ release from the endoplasmic reticulum. Thus, it seems that activating the purinergic P2 receptor may modulate GI motility by acting on ICCs in the small intestine.


Subject(s)
Adenosine , Adenosine Triphosphate , Animals , Endoplasmic Reticulum , Flufenamic Acid , Interstitial Cells of Cajal , Intestine, Small , Membranes , Mice , Muscle, Smooth , Niflumic Acid , Pacemaker, Artificial , Receptors, Purinergic , Receptors, Purinergic P2 , Suramin , Thapsigargin
2.
Article in English | WPRIM | ID: wpr-12124

ABSTRACT

Talniflumate is a phthalidyl ester of niflumic acid, which has potent analgesic and anti-inflammatory effects and is widely used to treat inflammatory disorders, such as rheumatoid arthritis. To screen the possible genetic factors affecting the pharmacokinetics (PK) of talniflumate, 23 male Korean volunteers were enrolled from two separate bioequivalence studies. All subjects received 740 mg (two tablets) talniflumate in a standard 2×2 cross-over model in a randomized order. For the genetic study, PK parameters of the reference drug were used. We used Illumina Human610Quad v1.0 DNA Analysis BeadChip for whole genome single nucleotide polymorphism (SNP) analysis and whole genome genotyping data were processed by linear regression analysis for PK parameters. Whole genome analysis revealed 1498 significant SNPs (P < 0.0001) for Cmax, 65 significant SNPs (P < 0.0001) for T(max), and 1491 significant SNPs (P < 0.0001) for AUC(inf). For clinical pharmacological purposes, we selected SNPs from drug metabolizing enzymes and transporters, and analyzed the PK parameters of various genotypes. Two SNPs (rs11165069 from ABCA4 (p=0.00002); rs17847036 from CYP2C9 (p=0.000001)) showed significant associations with talniflumate C(max). In the T(max) group, two SNPs (rs3787555 from CYP24A1 (p=0.00035); rs2275034 from ABCA4 (p=0.000587)) showed significant associations with talniflumate T(max). In the AUC(inf) group, two SNPs (rs11165069 from ABCA4 (p=0.00002); rs12461006 from SLC1A6 (p=0.00008)) exhibited significant associations with talniflumate absorption. These results show that genetic factors could affect the PK parameters, and provide information that may be used in the development of personalized talniflumate therapy.


Subject(s)
Absorption , Arthritis, Rheumatoid , Cytochrome P-450 CYP2C9 , DNA , Genome , Genotype , Humans , Linear Models , Male , Mass Screening , Niflumic Acid , Pharmacogenetics , Pharmacokinetics , Polymorphism, Genetic , Polymorphism, Single Nucleotide , Therapeutic Equivalency , Vitamin D3 24-Hydroxylase , Volunteers
3.
Article in Chinese | WPRIM | ID: wpr-236381

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effect of chloride channel blocker--niflumic acid (NFA) on the pathological process of hypoxia hypercapnia-induced pulmonary vasoconstriction in rats.</p><p><b>METHODS</b>We used the model of hypoxia hypercapnia-induced pulmonary vasoconstriction rats, and divided the second, third branch pulmonary artery rings randomly into four groups (n = 8): control group (N group), hypoxia hypercapnia group (H group), DMSO incubation group (HD group), niflumic acid group (NFA group). Under acute hypoxia hypercapnia conditions, we observed the effects of the three stages of hypoxia hypercapnia-induced pulmonary vasoconstriction (HHPV) incubated by NFA in the second, third brach pulmonary artery rings. At the same time, the values of rings' tension changings were recorded via the method of hypoxia hypercapnia conditions reactivity. And investigated the effect of NFA to HHPV.</p><p><b>RESULTS</b>(1) Under the hypoxia hypercapnia condition, we observed a biphasic pulmonary artery contractile (the phase I rapid contraction and vasodilation; the phase II sustained contraction) response in both the second and the third branch pulmonary artery rings compared with the control group (P < 0.05 , P < 0.01); (2) The second and third pulmonary artery rings incubated by NFA which phase II persistent vasoconstriction were significantly attenuated compared with the H group (P < 0.05 , P < 0.01).</p><p><b>CONCLUSION</b>The blocker of the chloride channels attenuates the second and third branch pulmonary artery rings constriction in rat, especially the phase II persistent vasoconstriction, so then have an antagonistic effect on HHPV.</p>


Subject(s)
Animals , Chloride Channels , Hypercapnia , Hypoxia , Niflumic Acid , Pharmacology , Pulmonary Artery , Pulmonary Circulation , Rats , Vasoconstriction
4.
Chinese Journal of Cardiology ; (12): 413-417, 2014.
Article in Chinese | WPRIM | ID: wpr-316446

ABSTRACT

<p><b>OBJECTIVE</b>To explore the impact of niflumic acid (NFA) on connexin 43 (Cx43) expression in smooth muscle cells of mesenteric small artery from spontaneously hypertensive rats (SHR).</p><p><b>METHODS</b>Blood pressure of Wistar rats and spontaneously hypertensive rats (SHR) was measured by the tail cuff method. Relaxation and contraction of mesenteric small artery from Wistar rat and SHR were evaluated by pressure myograph system under various concentrations of NFA. Protein Cx43 expression on primary cultured mesenteric smooth muscle cells from Wistar rats and SHR was detected in the absence and presence of various NFA concentrations by Western blot.</p><p><b>RESULTS</b>Phenylephrine resulted in mesenteric small arteries contraction [(193 ± 13.5) µm], while NFA (3×10(-4) mol/L) could relax the artery [(275 ± 17.1) µm]. The relaxation response in Wistar rats was significantly stronger than that in SHR (P < 0.05). Cx43 expression of the first level branch and the third branch mesenteric artery of SHR were higher than the corresponding branch vessels of Wistar rats, and the Cx43 expression of the third branches of mesenteric artery was higher than that of the first branch (F = 1 014.43, P < 0.01). Cx43 expression in primary cultured mesenteric smooth muscle cells was significantly downregulated post NFA treatment in a concentration dependent manner.</p><p><b>CONCLUSION</b>In the SHR mesenteric small arteries, Cx43 may be involved in smooth muscle cells communication, thereby affecting vascular contraction and relaxation responses.NFA could downregulate the expression of Cx43 in SHR mesenteric artery vascular smooth muscle cells and induce vasodilation.</p>


Subject(s)
Animals , Connexin 43 , Metabolism , Male , Mesenteric Arteries , Metabolism , Muscle, Smooth, Vascular , Cell Biology , Myocytes, Smooth Muscle , Metabolism , Niflumic Acid , Pharmacology , Rats , Rats, Inbred SHR , Rats, Wistar , Vasodilator Agents , Pharmacology
5.
Article in Chinese | WPRIM | ID: wpr-358676

ABSTRACT

<p><b>OBJECTIVE</b>To explore the modulatory effect of niflumic acid (NFA) on gamma aminobutyric acid (GABA)-activated currents of dorsal root ganglion (DRG) neurons in rat.</p><p><b>METHODS</b>The whole-cell patch-clamp technique was used to record the NFA- and GABA-activated currents in neurons freshly dissociated from rat DRG neurons.</p><p><b>RESULTS</b>Application of NFA(0.1 - 100 micromol/L) could induce concentration-dependent outward currents in some cells (21/48,43.75%), and GABA (0.1 - 100 micromol/L) could induce concentration-dependent inward currents in some cells(150/159,94.32%). NFA-(100 micromol/L) and GABA-(100 micromol/L) activated currents were (0.27 +/- 0.06) nA (n = 12) and (1.29 +/- 0.72) nA (n = 53) respectively. However, pre-application of NFA (0.1 - 100 micromol/L) could inhibit the GABA-activated inward current which was identified to be GABAA receptor-mediated current. The inhibitory effects of NFA were concentration-dependent. NFA could not alter the EC50 (about 30 micromol/L) and inverse potential (about -10 mV) of GABA-activated current (P > 0.05).</p><p><b>CONCLUSION</b>Pre-application of NFA exerts a more strong inhibitory effect on the peak value of GABA-activated current.</p>


Subject(s)
Animals , Cell Separation , Cells, Cultured , Ganglia, Spinal , Physiology , Neurons , Physiology , Niflumic Acid , Pharmacology , Patch-Clamp Techniques , Rats , Rats, Sprague-Dawley , gamma-Aminobutyric Acid , Metabolism
6.
Article in Chinese | WPRIM | ID: wpr-358660

ABSTRACT

<p><b>OBJECTIVE</b>To explore the modulatory effect of niflumic acid and blocker of calcium channel on the desensitization of gamma aminobutyric acid (GABA)-activated currents in dorsal root ganglion(DRG) neurons from rat.</p><p><b>METHODS</b>The whole-cell patch-clamp technique was used to observe the modulatory effect of niflumic acid and blocker of calcium channel on the desensitization of GABA-activated currents in neurons freshly dissociated from rat DRG neurons.</p><p><b>RESULTS</b>Application of GABA (0.1-1 000 micromol/L) could induce concentration-dependent inward currents in some cells (212/223, 95.11%). GABA-(100 micromol/L) activated currents was (1.32 +/- 0.74) nA (n = 84). However, pre-application of niflumic acid (1-100 micromol/L) and nitrendipine (specific blocker of L-calcium channel)(0.1-30 micromol/L) could inhibit the GABA-activated inward current which was identified to be GABAA receptor-mediated current. The inhibitory effects of niflumic acid and nitrendipine were concentration-dependent. The suppression rate of 10 micromol/L niflumic acid and nitrendipine to GABA-activated currents were (31.60% +/- 4.87%) (n = 19) and (43.60% < or = 5.10%) (n = 5), respectively. The desensitization of GABA-activated currents had double exponential characteristic. Tau value was (14.68 +/- 5.11) s (n = 6) and (175.8 +/- 42.67) s (n = 6, r = 0.9647), respectively. Pre-application of niflumic acid (100 micromol/L) and nickel chloride (nonspecific blocker of L-calcium channel) (100 micromol/L) altered tau value of the desensitization of GABA-activated currents, tau value reduced for (4.64 +/- 2.21) s (n = 3), (43.70 +/- 14.34) s ( n = 3, r = 0.9548) and (4.64 +/- 2.21) s (n = 3), (43.70 +/- 14.34) s (n = 3, r = 0.9721).</p><p><b>CONCLUSION</b>Pre-application of niflumic acid exerts a more strong inhibitory effect on the peak value of GABA-activated current, which possibly is through blocking the calcium-activated chloride ion channel to accelerate the desensitization of GABA-activated currents.</p>


Subject(s)
Animals , Animals, Newborn , Calcium Channel Blockers , Pharmacology , Calcium Channels, L-Type , Ganglia, Spinal , Physiology , Membrane Potentials , Physiology , Neurons , Physiology , Niflumic Acid , Pharmacology , Nitrendipine , Pharmacology , Patch-Clamp Techniques , Rats , Rats, Sprague-Dawley , gamma-Aminobutyric Acid , Pharmacology
7.
Article in English | WPRIM | ID: wpr-647473

ABSTRACT

BACKGROUND AND OBJECTIVES: Nucleotide binding to purinergic P2Y receptors contributes to the regulation of fluid and ion transport in the middle ear epithelial cells. Here, we investigated the regulatory mechanism of the P2Y2 receptor agonist, uridine-5'-triphosphate (UTP), on Cl- transport in cultured normal human middle ear epithelial (NHMEE) cells. MATERIALS AND METHOD: Electrophysiological measurements were performed in monolayers of cultured NHMEE cells. Short circuit currents (Isc) were measured from the cells mounted in Ussing chambers under various conditions. RESULTS: Apical addition of UTP in presence of amiloride evoked a transient rise and a sustained response in Isc due to Cl- efflux. Application of different Cl- channel blockers to the apical side of the cells significantly decreased UTP-induced Isc. Niflumic acid (NFA), a known blocker of Ca(2+)-activated chloride channels (CACC), and CFTRinh172, a selective inhibitor of cystic fibrosis transmembrane conductance regulator (CFTR), partially inhibited the UTP-induced Cl- secretion, respectively. CONCLUSION: Cl- transport across the airway epithelia plays a predominant role in regulating airway hydration. In this study, UTP is shown to increase both CACC and CFTR-dependent Cl- secretion in NHMEE cells, suggesting their role in fluid and ion transport in the middle ear epithelium.


Subject(s)
Amiloride , Chloride Channels , Cystic Fibrosis , Cystic Fibrosis Transmembrane Conductance Regulator , Ear, Middle , Epithelial Cells , Epithelium , Humans , Ion Channels , Ion Transport , Niflumic Acid , Receptors, Purinergic P2Y , Uridine Triphosphate
8.
Acta Physiologica Sinica ; (6): 743-750, 2008.
Article in English | WPRIM | ID: wpr-302495

ABSTRACT

The mechanism by which niflumic acid (NFA), a Cl(-) channel antagonist, hyperpolarizes the smooth muscle cells (SMCs) of cochlear spiral modiolar artery (SMA) was explored. Guinea pigs were used as subjects and perforated patch clamp and intracellular recording technique were used to observe NFA-induced response of SMC in the acutely isolated SMA preparation. The results showed that bath application of NFA, indanyloxyacetic acid 94 (IAA-94) and disodium 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) caused hyperpolarization and evoked outward currents in all cells at low resting potential (RP), but had no effects in cells at high RP. In the low RP SMCs, the average RP was about (-42.47+/-1.38) mV (n=24). Application of NFA (100 mumol/L), IAA-94 (10 mumol/L) and DIDS (200 mumol/L) shifted the RP to (13.7+/-4.3) mV (n=9, P<0.01), (11.4+/-4.2) mV (n=7, P<0.01) and (12.3+/-3.7) mV (n=8, P<0.01), respectively. These drug-induced responses were in a concentration-dependent manner. NFA-induced hyperpolarization and outward current were almost blocked by charybdotoxin (100 nmol/L), iberiotoxin (100 nmol/L), tetraethylammonium (10 mmol/L), BAPTA-AM (50 mumol/L), ryanodine (10 mumol/L) and caffeine (0.1-10 mmol/L), respectively, but not by nifedipine (100 mumol/L), CdCl2 (100 mumol/L) and Ca(2+)-free medium. It is concluded that NFA induces a release of intracellular calcium from the Ca(2+) stores and the released intracellular calcium in turn causes concentration-dependent and reversible hyperpolarization and evokes outward currents in the SMCs of the cochlear SMA via activation of the Ca(2+)-activated potassium channels.


Subject(s)
Animals , Arteries , Metabolism , Calcium , Physiology , Cochlea , Guinea Pigs , Large-Conductance Calcium-Activated Potassium Channels , Physiology , Membrane Potentials , Myocytes, Smooth Muscle , Physiology , Niflumic Acid , Pharmacology , Ryanodine , Pharmacology
9.
Article in Chinese | WPRIM | ID: wpr-254562

ABSTRACT

<p><b>AIM</b>To investigate the role of calcium-activated chloride channels and the Cl- channel blockers niflumic acid (NFA) and indanyloxyacetic acid (IAA-94) in the regulation of vascular contraction induced by phenylephrine (PE).</p><p><b>METHODS</b>The PE-induced contraction in rat pulmonary artery was observed by using routine blood vascular perfusion in vitro. The fluorescence Ca2+ indicator Fura-2/AM was used to observe intracellular free Ca2+ concentration ([Ca2+]i) of rat pulmonary artery smooth muscle cells (PASMCs) which were obtained by the acute enzyme separation method (collagenase I plus papain) on NFA and IAA-94 effects on PE-induced contraction. Changes of [Ca2+]i in PASMCs were measured by spectrofluorometry.</p><p><b>RESULTS</b>The anion channel blockers NFA and IAA-94 produced inhibitory effects on PE-induced contractions in the pulmonary artery. NFA and IAA-94 negligibly affected the KCl-induced pulmonary artery contractions. PE could increase [Ca2+]i but NFA and IAA-94 negligibly affected it.</p><p><b>CONCLUSION</b>Calcium-activated chloride channels contribute to the agonist-induced pulmonary artery contractions under physiological conditions, which may be a new clue to investigate the hypoxic pulmonary vasoconstriction.</p>


Subject(s)
Animals , Calcium , Physiology , Chloride Channels , Physiology , Glycolates , Pharmacology , Male , Muscle, Smooth, Vascular , Physiology , Niflumic Acid , Pharmacology , Phenylephrine , Pharmacology , Pulmonary Artery , Physiology , Rats , Rats, Sprague-Dawley , Vasoconstriction
10.
Chinese Journal of Hematology ; (12): 170-174, 2005.
Article in Chinese | WPRIM | ID: wpr-229875

ABSTRACT

<p><b>OBJECTIVE</b>To explore the effects of chloride channels on the regulation of platelet cytoplasmic free calcium concentration ([Ca2+]i) and platelet aggregation (PAG).</p><p><b>METHODS</b>Freshly separated platelets were activated by thrombin. Chloride channel blockers DIDS or NFA and calcium channel blockers SK&F96365 or nifedipine were added to study the effects on platelet [Ca2+]i and PAG by a single reagent or the combination of reagents and find out the interactions among DIDS, NFA, SK&F96365 and nifedipine.</p><p><b>RESULTS</b>Both DIDS and NFA could inhibit the thrombin (1 U/ml) induced PAG in a dose-dependent manner, whereas had little effect on resting [Ca2+]i. As compared with the control group, DIDS, SK&F96365 and Nifedipine could significantly reduce the PAG, Ca2+ release and Ca2+ influx in thrombin activated platelet (P < 0.05). The combination of DIDS and SK&F96365 had greater effects in reducing the PAG, Ca2+ release and Ca2+ influx than either reagent alone (P < 0.05). The combination of DIDS and nifedipine also had greater effect than each alone in reducing Ca2+ release (P < 0.05). The combination of NFA and SK&F96365 weakened each other's effect on Ca2+ release (P < 0.05), while NFA and nifedipine weakened each other's effects on PAG, Ca2+ release and Ca2+ influx in thrombin activated platelet (P < 0.05).</p><p><b>CONCLUSION</b>DIDS and NFA have no effect on the resting [Ca2+]i and the leak calcium influx of platelet. DIDS can inhibit the Ca2+ release, Ca2+ influx and PAG of platelet induced by thrombin, while NFA can only inhibit the Ca2+ release. The chloride channel and calcium channel blockers have interactions in affecting resting [Ca2+]i and PAG of platelet. The opening of chloride channel can influence the cellular calcium movement of platelet.</p>


Subject(s)
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid , Pharmacology , Adult , Blood Platelets , Cell Biology , Metabolism , Calcium , Metabolism , Calcium Channel Blockers , Pharmacology , Cells, Cultured , Chloride Channels , Physiology , Cytoplasm , Metabolism , Drug Interactions , Humans , Imidazoles , Pharmacology , Nifedipine , Pharmacology , Niflumic Acid , Pharmacology , Platelet Aggregation , Thrombin , Pharmacology
11.
Article in Korean | WPRIM | ID: wpr-77479

ABSTRACT

OBJECTIVE: In the central nervous system, gamma-aminobutyric acid (GABA) is well known to act as an inhibitory neurotransmitter by hyperpolarizing postsynaptic neurons through gating GABA-activated Cl- channels. To date, however, the functional roles of GABA remain unclear in the autonomic nervous system. In the present study, we characterize GABA-activated Cl- currents in the neurons of major pelvic ganglia (MPG). METHODS: MPG neurons, located on the lateral surfaces of the prostate gland, from male rats were enzymatically dissociated. Ionic currents were recorded using whole-cell variant patch-clamp technique. Membrane potential was recorded under current clamp mode. Current traces were filterd at 2kHz by using 4-pole Bassel filter in the amplifier. RESULTS: Application of GABA (100micrometer) induced inward currents in the neurons, with holding potentials being maintained below the Cl- equilibrium potential (ECl). The GABA response was concentration-dependent and its reversal potential was close to the theoretical ECl. The GABA-induced Cl- currents were largely blocked by bicuculline (10micrometer, n=5), a GABAA receptor antagonist, but were not affected by 9-AC and niflumic acid, chloride channel blockers. GABA also produced significant membrane depolarization (19mV, n=28). As in the case of the Cl- currents, the GABA-induced depolarizations were largely blocked by bicuculline(10micrometer, n=6), but not by DIDS(50micrometer, n=4), another chloride channel blocker. CONCLUSION: The data suggest that GABAergic roles may be due to it's activation of excitatory GABAA receptors, which are expressed in MPG neurons.


Subject(s)
Animals , Autonomic Nervous System , Bicuculline , Central Nervous System , Chloride Channels , gamma-Aminobutyric Acid , Ganglia , Humans , Male , Membrane Potentials , Membranes , Neurons , Neurotransmitter Agents , Niflumic Acid , Patch-Clamp Techniques , Prostate , Rats
12.
Article in English | WPRIM | ID: wpr-727787

ABSTRACT

To investigate whether VacA (vacuolating toxin) produced by Helicobacter pylori Korean stain 99 induces intestinal secretion, purified VacA was added to T84 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of low pH-pretreated VacA increased short circuit current (Isc). The effect was time- and dose-dependent and saturable. The time-to-peak Isc was concentration-dependent. Chloride channel inhibitors, niflumic acid or 5- nitro-2- (3-phenylpropylamino) -benzoate (NPPB), inhibited VacA-stimulated Isc. Carbachol (CCh) -induced increase of Isc was prolonged by the addition of VacA to the mucosal side only. The effect was unaltered by the addition of niflumic acid. VacA did not show cytopathic effects. These studies indicate that VacA is a nonlethal toxin that acts in a polar manner on T84 monolayers to potentiate Cl secretion and the response to CCh secretion without decrease in monolayer resistance. VacA may contribute to diarrhea diseases in human intestinal epithelial cells.


Subject(s)
Carbachol , Chloride Channels , Diarrhea , Epithelial Cells , Helicobacter pylori , Helicobacter , Humans , Intestinal Secretions , Niflumic Acid
13.
Acta Physiologica Sinica ; (6): 160-164, 2003.
Article in Chinese | WPRIM | ID: wpr-318924

ABSTRACT

The purpose of this work was to investigate the effects of niflumic acid (NFA), a chloride channel blocker, on the proliferation of human hepatoma cell line (HHCC). Cell proliferation was analyzed by cell count and MTT assay. Cell cycle analysis was carried out by flow cytometry. [Ca(2+)](i) was determined by laser scanning confocal system. It was found that NFA decreased significantly the cell number and the MTT optical density (OD) of HHCC cells, and that the OD value was reversed after washout of NFA. Compared with control, NFA blocked cell cycle progression in G(1) phase. Extracellular application of NFA (100 micromol/L) induced a rapid decrease in [Ca(2+)](i). These findings demonstrate that blockage of chloride channels by NFA induces growth arrest of HHCC in G(1) phase, which may be due to the inhibition of Ca(2+)/CaM-dependent signaling pathways.


Subject(s)
Calcium , Metabolism , Calmodulin , Metabolism , Carcinoma, Hepatocellular , Pathology , Cell Line, Tumor , Cell Proliferation , Chloride Channels , Humans , Liver Neoplasms , Pathology , Niflumic Acid , Pharmacology
15.
Article in English | WPRIM | ID: wpr-728244

ABSTRACT

To explore whether Cl- channel blockers interact with the ATP-sensitive K+ (KATP) channel, I have examined the effect of two common Cl- channel blockers on the KATP channel activity in isolated rat ventricular myocytes using patch clamp techniques. In inside-out patches, 4,4'-diisothio-cyanatostilbene-2,2'-disulfonic acid (DIDS) and niflumic acid applied to bath solution inhibited the KATP channel activity in a concentration-dependent manner with IC50 of 0.24 and 927 muM, respectively. The inhibitory action of DIDS was irreversible whereas that of niflumic acid was reversible. Furthermore, DIDS-induced block was not recovered despite exposure to ATP (1 mM). In cell-attached and inside-out patches, DIDS blocked the pinacidil- or 2,4-dinitrophenol (DNP)-induced KATP channel openings. In contrast, niflumic acid did not block the pinacidil-induced KATP channel openings in inside-out patches, but inhibited it in cell-attached patches. DIDS and niflumic acid produced additional block in the presence of ATP and did not affect current-voltage relationship and channel kinetics. All these results indicate that DIDS among Cl- channel blockers specifically blocks the cardiac KATP channel.


Subject(s)
2,4-Dinitrophenol , 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid , Adenosine Triphosphate , Animals , Baths , Inhibitory Concentration 50 , Kinetics , Muscle Cells , Niflumic Acid , Patch-Clamp Techniques , Rats
16.
Article in English | WPRIM | ID: wpr-727963

ABSTRACT

Loss of synaptic transmission and accumulation of extracellular K+((K+)o) are the key features in ischemic brain damage. Here, we examined the effects of several K+ channel modulators on the early ischemic changes in population spike (PS) and (K+)o in the CA1 pyramidal layer of the rat hippocampal slice using electrophysiological techniques. After onset of anoxic aglycemia (AA), orthodromic field potentials decreased and disappeared in 3.3 +/- 0.22 min (mean +/- SEM, n = 40). The hypoxic injury potential (HIP), a transient recovery of PS appeared at 6.0 +/- 0.25 min (n = 40) in most slices during AA and lasted for 3.3 +/- 0.43 min. (K+)o increased initially at a rate of 0.43 mM/min (Phase 1) and later at a much faster rate (12.45 mM/min, Phase 2). The beginning of Phase 2 was invariably coincided with the disappearance of HIP. Among K+ channel modulators tested such as 4-aminopyridine (0.03, 0.3 mM), tetraethylammonium (0.1 mM), NS1619 (0.3 ~ 10 muM), niflumic acid (0.1 mM), glibenclamide (40 muM), tolbutamide (300 muM) and pinacidil (100 muM), only 4-aminopyridine (0.3 mM) induced slight increase of (K+)o during Phase 1. However, none of the above agents modulated the pattern of Phase 2 in (K+)o in response to AA. Taken together, the experimental data suggest that 4-aminopyridine-sensitive K+ channels, large conductance Ca2+/-activated K+ channels and ATP-sensitive K+ channels may not be the major contributors to the sudden increase of (K+)o during the early stage of brain ischemia, suggesting the presence of other routes of K+ efflux during brain ischemia.


Subject(s)
4-Aminopyridine , Animals , Brain , Brain Ischemia , Glyburide , Hip , Ischemia , Niflumic Acid , Pinacidil , Rats , Synaptic Transmission , Tetraethylammonium , Tolbutamide
17.
Braz. j. med. biol. res ; 23(9): 789-94, 1990. ilus, tab
Article in English | LILACS | ID: lil-92340

ABSTRACT

Binding of the anti-inflammatory drug niflumic acid to serum albumin was measured by equilibrium dialysis and the dissociation constants were determined. The maximal binding capacity was 36 mol niflumic acid per mol albumin. Most of the binding sites were of low affinity, only six having dissociation constants below 1 mM. At the plsma concentrations most frequently used in eperimental work, the high affinity sites account for more than 99% of the albumin-bound influmic acid


Subject(s)
Animals , Rats , Niflumic Acid/metabolism , Dialysis/methods , Liver/metabolism , Serum Albumin, Bovine/metabolism , Albumins , Binding Sites , Least-Squares Analysis , Spectrophotometry
18.
Rev. odontol. Univ. Säo Paulo ; 2(2): 120-6, abr.-jun. 1988. tab
Article in Portuguese | LILACS, BBO | ID: lil-80413

ABSTRACT

Neste trabalho procurou-se avaliar os efeitos dos antiinflamatórios näo esteróides: Indometacina (indocid), Butazona (Fenilbutazona), Clinoril (Sulindac), Naprosin (Naproxen), Benflogin (Cloridrato de Benzidamina) e Inflaril (Acido neflúmico) nos leucogramas de ratos portadores de um processo inflamatório crônico provocado pela introduçäo intradérmica de lamínulas de vidro nos períodos de 3, 12 e 18 dias. O sangue para a contagem total dos leucócitos, eletrônica e diferencial, esfregaço, foi obtido por punçäo intracardíaca (Burhoe). A Indometacina, o Clinoril e a Butazona indicaram diminuiçäo de linfócitos e eosinófilos e aumento de monócitos e neutrófilos em todos os períodos e observaçäo em todos os períodos; o Inflaril reduziu o número de linfócitos, neutrofilia e eosinopenia em todos os períodos; o Inflaril reduziu o número de linfócitos e eosinófilos de aumentou os monócitos, com exceçäo de 3§ período, e os neutrófilos nos três períodos; e o Benflogin elevou os linfócitos na 1ª e 3ª fases, e os monócitos nos três períodos, e reduziu os neutrófilos nos dois primeiros, e os eosinfófilos nos dois últimos períodos. Todas as drogas usadas provocaram reduçäo de leucócitos em todos os períodos de tratamento, exceçäo feita ao Naprosin no 3§, ao Benflogin no 2§ e ao Inflaril no 1§ e 2§ períodos


Subject(s)
Rats , Animals , Anti-Inflammatory Agents, Non-Steroidal/blood , Niflumic Acid/administration & dosage , Niflumic Acid/blood , Benzydamine/administration & dosage , Benzydamine/blood , Indomethacin/administration & dosage , Indomethacin/blood , Naproxen/administration & dosage , Naproxen/blood , Phenylbutazone/administration & dosage , Phenylbutazone/blood , Sulindac/administration & dosage , Sulindac/blood
19.
Rev. UNIMAR ; 7(1): 71-84, out. 1985.
Article in Portuguese | LILACS | ID: lil-29618

ABSTRACT

Foi estudado o efeito do ácido niflúmico sobre a metabolizaçäo do piruvato, da frutose e do glicogênio endógeno pelo fígado de rato perfundido isoladamente, tendo-se acompanhado também o consumo de oxigênio. Na faixa de concentraçäo entre 6 e 100 micron M, o ácido niflúmico ativou o consumo de oxigênio, chegando a duplicar a taxa respiratória em relaçäo ao controle, dependendo das condiçöes experimentais. Na mesma faixa de concentraçäo, o ácido niflúmico inibiu a gluconeogênese (a partir de piruvato e frutose), ativou a glicólise e a glicogenólise e aumentou a razäo L-lactato/piruvato. A frutólise foi ativada por concentraçöes até 30 micron M, tendo sido inibida por concentraçöes maiores. A respiraçäo inibida pelo cianeto näo foi mais ativada pelo ácido niflúmico; a respiraçäo sensível ao atractilosídeo, porém, foi ativada. Esses efeitos foram provavelmente devidos à açäo desacoplante do ácido niflúmico, conforme foi demonstrado previamente com mitocôndrias isoladas. Há, porém, dados que parecem indicar que, a nível de célula intata, a açäo do ácido niflúmico näo está restrita às mitocôndrias


Subject(s)
Rats , Animals , Male , Liver/metabolism , Niflumic Acid/pharmacology , Perfusion
20.
Rev. UNIMAR ; 7(1): 123-32, out. 1985.
Article in Portuguese | LILACS | ID: lil-29641

ABSTRACT

O ácido niflúmico, droga anti-inflamatória, tem amplo efeito sobre a metabolizaçäo do glicerol. Ele inibe a síntese de glucose a partir de glicerol (neoglicogênese, e ativa a produçäo de L-lactato. A respiraçäo , mesmo já estando ativada pelo glicerol, é adicionalmente ativada pelo ácido niflúmico. A causa parece estar ligada à afinidade das membranas mitocondriais pelo ácido niflúmico, o que causa desacoplamento da fosforilaçäo oxidativa. Com efeito, estudos cinéticos mostram que o fígado liga reversivelmente certa quantidade de ácido niflúmico. Há portanto, um complexo equilíbrio näo só entre a albumina circulante e o meio intracelular, mas também entre o meio intracelular e as membranas mitocondriais


Subject(s)
Rats , Animals , Male , Liver/metabolism , Glycerol/metabolism , Niflumic Acid/pharmacology , Perfusion
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