Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The insulin-stimulated glucose transporter in rat adipocytes was inhibited by two protein kinase inhibitors, staurosporine (SSP) and H-7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine). However, whereas SSP (10 microM) blocked the insulin-dependent translocation of glucose transporter, H-7 (3 mM) did not. The latter inhibited glucose transporter activity not only in cells, but also in reconstituted liposomes. On the other hand, SSP blocked both the action of insulin and the insulinomimetic action of GTP gamma S (Guanosine 5'-O-(3-thiotriphosphate)). GTP gamma S had distinct effects on the glucose transport and cAMP phosphodiesterase (PDE) activities. It is suggest that H-7 may inhibit glucose transport activity per se; a SSP sensitive protein kinases (protein kinase C isoforms?) may be involved in cascade of the insulin action on glucose transporter as modulated by GTP gamma S; and glucose transport and PDE activities may be regulated by distinct GTP gamma S-sensitive factors.
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PMID:Primary sites of actions of staurosporine and H-7 in the cascade of insulin action to glucose transport in rat adipocytes. 847 33

The present work was designed to study the pharmacological control of the receptor-mediated activation of human neutrophils by tolfenamic acid (2(-)[(3-chloro-2-methylphenyl)-amino]benzoic acid). Tolfenamic acid inhibited in a concentration-dependent manner the degranulation response and Ca2+ influx in neutrophils activated either by the chemotactic peptide fMLP (N-formyl-methionyl-leucylphenylalanine) or Ca2+ ionophore A23187 (calcimycin). When fMLP was used to activate neutrophils, tolfenamic acid (30 microM) reduced Ca2+ influx by 50% and degranulation by 20%. A23187-triggered Ca2+ influx and degranulation were inhibited by 60% and 40%, respectively, by 30 microM tolfenamic acid. Tolfenamic acid did not inhibit the release of Ca2+ from intracellular stores induced either by fMLP or A23187. To confirm the inhibition of receptor-mediated cation influx by tolfenamic acid, the agonist induced Mn2+ influx was studied in Ca2+ free medium. Tolfenamic acid (10-30 microM) reduced fMLP-stimulated Mn2+ influx in neutrophils in a concentration-dependent manner. The simultaneous Ca2+ release from intracellular stores was not affected. Protein kinase C activity in sonicated human neutrophils and the purified enzyme from rat brain were inhibited by the protein kinase inhibitor H-7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine) but not by tolfenamic acid. Both failed to inhibit neutrophil degranulation induced by phorbol myristate acetate, a protein kinase C activator. Tolfenamic acid (100 microM) increased the cellular cAMP levels up to 1.3-fold in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine. No effects on cellular cGMP levels were found.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of human neutrophil function by tolfenamic acid involves inhibition of Ca2+ influx. 854 43

1. Protein kinase modulation of gamma-aminobutyric acid-A (GABAA)- and glycine-activated Cl- currents in freshly dissociated, morphologically identified rabbit retinal rod bipolar cells was studied under voltage clamp with the use of the whole cell patch-clamp technique. Responses to pulses of GABA and glycine were monitored before, during, and after application of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA) and protein kinase C (PKC) activators, inactive analogues, and inhibitors. 2. Bath perfusion with either forskolin, an adenylate cyclase activator, or its inactive analogue, 1,9 dideoxyforskolin, reduced the GABA-activated Cl- currents by 30-50%; coapplication of N-[2-(Methylamino)ethyl]-5-isoquinolinesulfonamide hydrochloride (H-8), a PKA inhibitor, did not prevent the forskolin effects. The membrane-permeable cAMP analogues, 8-bromo-cAMP and 8-(4-Chlorophenylthio)-cAMP, and intracellularly dialyzed cAMP, did not modulate either the GABA- or glycine-activated Cl- current. Perfusion of the phosphodiesterase inhibitor 3-isobutyl-1-methylxantine (IBMX) had no direct effect on the GABA-activated current and did not alter the results with cAMP or its membrane-permeable analogues. Collectively, these results make it very unlikely that PKA represents an important mechanism of either GABAA or glycine channel modulation in the rabbit rod bipolar cell. 3. Although the isoquinoline sulfonamide protein kinase inhibitor H-8 was without discernible effect, the related compounds 1-(5-Isoquinolinesulfonyl)-2-methylpiperazine dihydrochlorine (H-7) and N-(2-Aminoethyl)-5-isoquinolinesulfonamide dihydrochloride (H-9) both dramatically reduced the GABA response. H-7 also strongly reduced the response to glycine, whereas H-8 had no effect and H-9 had an intermediate effect. Because only certain members of this inhibitor class of agents proved effective, and their effectiveness appeared unrelated to the established activity profiles, these agents probably inhibit the Cl- currents in a phosphorylation-independent manner. Direct interaction of these inhibitors with binding sites in the GABAA receptor-channel complex has been previously reported in some other preparations. 4. The phorbol ester and PKC activator phorbol 12,13 dibutyrate (PDB) led to a 35-55% reduction in the GABA-activated Cl- current of the rod bipolar cell. The broad-spectrum kinase inhibitor staurosporine, and the more PKC-specific inhibitor calphostin C, had no direct effect on GABA responses, but prevented Cl- current reduction when coapplied with PDB. Phorbol 12-myristate 13-acetate (PMA) reduced the GABA-activated current in a fashion very similar to PDB. Staurosporine and calphostin C blocked the PMA effect. No reduction of Cl- current was seen with the inactive analogue, 4-alpha-PMA, used as a control for PKC-independent phorbol ester effects. 5. PDB effectively reduced the GABA-activated Cl- current of the rod bipolar cell at low concentrations, whereas PMA had a diminished effect at low concentrations. This is consistent with the reported concentration-dependent abilities of these agents to promote translocation of PKC-alpha immunoreactivity from the membrane to the cytosolic compartment in the rabbit retinal rod bipolar cell. Collectively, the data from phorbol esters, inactive analogues, and kinase inhibitors support the existence of a PKC-mediated mechanism for GABA-activated Cl- current reduction in these cells. 6. The naphthalenesulfonamide PKC activator N-(n-Heptyl)-5-chloro-1-naphthalenesulfonamide (SC-10) also potently and reversibly reduced the GABA-activated current. Staurosporine and calphostin C eliminated this effect. When the nonhydrolyzable guanosine 5'-triphosphate (GTP) analogue guanosine 5'-O-(3-thiotriphosphate) tetralithium salt (GTP-gamma-S) replaced GTP in the recording pipette, the SC-10-mediated GABA current reduction became irreversible.(ABSTRACT TRUNCATED)
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PMID:Protein kinase modulation of GABAA currents in rabbit retinal rod bipolar cells. 893 Feb 56

1. An inward current (I[in]) was produced by gamma-aminobutyric acid (GABA) and muscimol, but not by baclofen, in an identifiable giant neuron type, v-LCDN (ventral-left cerebral distinct neuron), of an African giant snail (Achatina fulica Ferussac) under voltage clamp. 2. The pharmacological features of the excitatory GABA receptors in this Achatina neuron type, termed the Achatina muscimol II type GABA receptors, were mainly comparable to those of the mammalian GABA(C) receptors. 3. It was demonstrated in the present study that the following inhibitors for intracellular signal transduction systems showed no significant effect on the I(in) produced by GABA in this Achatina neuron type: H-7 [1-(5-isoquinolinyl sulfonyl)-2-methylpiperazine], an inhibitor of cyclic AMP-dependent protein kinase (PKA), cyclic GMP-dependent protein kinase (PKG) and protein kinase C (PKC); H-8 (N-[2-(methylamino)-ethyl]-5-isoquinolinesulfonamide), a PKA and PKG inhibitor; H-9 [N-(2-aminoethyl)-5-isoquinolinesulfonamide], a PKA inhibitor; staurosporine ((9alpha,10beta,11beta,13alpha)-(+)-2,3,10,11,12 ,13-hexahydro-10-methoxy-9-methyl-11-(methylamino)-9,13-epoxy-1H,9H-d iindolo[1,2,3-gh: 3',2',1'-1m]pyrrolo[3,4-j] [1,7]benzodiazonin-1-one), a PKA and PKC inhibitor; KT5823 ((8R,9S, 11S)-9-methoxy-9-methoxycarbonyl-2N,8-dimethyl-2,3,9,10-tetrahydro-8,11- epoxy-1H,8H,11H-2,7b,11a-triazadibenzo[a,g]cycloocta[c,d,e]- trinden-1-one), a PKG inhibitor; W-7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], a calmodulin inhibitor; ML-9 [1-(5-chloronaphthalene-1-sulfonyl-1H-hexahydro-1,4-diazepine hydrochloride], a myosin light-chain kinase inhibitor; genistein [5,7-dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one], a tyrosine protein kinase inhibitor; IBMX (3-isobutyl-1-methylxanthine), a cyclic nucleotide phosphodiesterase (PDE) inhibitor; fluphenazine nitrogen-mustard (2-chloroethyl)-4[3-(2-trifluoromethyl-10-phenothiazinyl)-propyl]p iperazine dihydrochloride), a calmodulin-dependent PDE inhibitor; calyculin A, a type 1 protein phosphatase inhibitor; and okadaic acid (9,10-deepithio-9,10-didehydroacanthifolicin), a type 1, 2A and 2B protein phosphatase inhibitor. 4. With these results, it was proposed that the excitatory Achatina muscimol II type GABA receptors in v-LCDN are not metabotropic but ionotropic.
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PMID:Effects of inhibitors for intracellular signal transduction systems on the inward current produced by GABA in a snail neuron. 950 77

ATP causes relaxation of the K(+)-contracted rat vas deferens. Possible sites of action were investigated. ATP and adenosine relaxed the vas deferens precontracted with 80 mM K(+); EC(50) values and maximal relaxations averaged, respectively, 760 microM and 56% for ATP and 74 microM and 30% for adenosine. The adenosine P1 receptor antagonist 8-(para-sulfophenyl)theophylline (8-SPT) reduced relaxations caused by adenosine and low concentrations of ATP, as did the Rp-diastereomer of adenosine 3',5'-cyclic phosphorothioate (Rp-cAMPS), an inhibitor of protein kinase A. The phosphodiesterase inhibitor 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro 20-1724) augmented responses to adenosine and low concentrations of ATP. alpha,beta-Methylene ADP, an inhibitor of 5'-nucleotidase, reduced relaxations caused by ATP to a similar extent as did 8-SPT. In the presence of an almost saturating concentration of adenosine, ATP caused further relaxation. Conversely, in the presence of ATP, adenosine had little effect. Like ATP, UTP and other nucleoside triphosphates relaxed the vas deferens. The P2 receptor antagonists reactive blue 2, acid blue 25 and 4,4'-diisothiocyanotostilbene-2,2'-disulphonate (DIDS) attenuated the relaxation caused by ATP; suramin, pyridoxalphosphate-6-azophenyl-2',4'-disulphonate (PPADS), Evans blue, trypan blue, reactive red 2 and brilliant blue G had no effect. Three non-selective inhibitors of protein kinases, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), staurosporine and (8R*,9S*,11S*)-(-)-9-hydroxy-9-carboxy-8-methyl-2,3,9,10-tetrahydro-8,11-epoxy-1H,8H,11H-2,7b,11a-triazadibenzo[a,g]cycloocta[cde]trinden-1-one (K-252b), markedly reduced the relaxation caused by ATP. The results indicate that adenosine, derived from enzymatic dephosphorylation, contributes to the relaxant effect of ATP, presumably by activation of a smooth muscle adenosine receptor linked to the accumulation of cAMP and activation of protein kinase A. Yet, the main part of the response to ATP is mediated by a site distinct from the adenosine receptor. The pharmacological properties of this site differ from known P2 receptor subtypes. Possibly, the nucleotide-evoked relaxation is due to a phosphoryl transfer catalyzed by an ecto-protein kinase.
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PMID:Nucleotide-evoked relaxation of rat vas deferens: possible mechanisms. 1183 57


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