Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Guanine nucleotides have been examined as to their effects on subclass-specific excitatory amino acid receptor-ligand interactions. Guanine nucleotides selectively inhibit L-[3H]glutamate binding to the N-methyl-D-aspartate (NMDA) recognition site while showing a lesser effect on [3H]kainate, [3H]alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate and sodium-dependent L-[3H]glutamate binding. Of the series of guanine nucleotides tested in the inhibition of NMDA-specific L-[3H]glutamate binding, GTP, GDP, 5'-guanylylimidodiphosphate and 5'-guanylylmethylenediphosphate were significantly more potent than GMP, cyclic GMP and guanosine. Scatchard analysis indicates that the GTP inhibition (IC50 = 28 microM) of this NMDA-specific L-[3H]glutamate binding results from a decrease in the affinity of L-glutamate for the NMDA receptor whereas no alteration in the number of binding sites is observed. A kinetic analysis indicates that this decrease in affinity may be attributed to a decrease in association rate whereas no change in dissociation rate is observed. GTP (25 microM) lowers the affinities of both NMDA agonists (NMDA, L-glutamate, L-aspartate, and L-homocysteate) and antagonists (D-2-amino-5-phosphonovalerate, D-2-amino-7-phosphonoheptanoate, and D-2-aminoadipate). Pretreatment of the synaptic plasma membranes with either pertussis or cholera toxin had no significant effect on the GTP inhibition of NMDA-specific L-[3H] glutamate binding. The data suggest that guanine nucleotides can negatively modulate the NMDA receptor; however, the mechanism of this modulation is unclear.
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PMID:Effects of guanine nucleotides on N-methyl-D-aspartate receptor-ligand interactions. 284 50

Incubation of [3H] inositol-labeled cultured rat aortic vascular smooth muscle cells with angiotensin II caused the dose- and time-dependent formation of inositol mono-, bis- and trisphosphates. Under these conditions, adenosine triphosphate (ATP) stimulated the formation of these inositol phosphates. The maximal reaction velocities obtained by ATP and angiotensin II were roughly the same. The doses of ATP giving half maximal and maximal reaction velocities were about 100 microM and 1 mM, respectively. This action of ATP was mimicked by other nucleotides such as adenosine diphosphate (ADP) and guanosine triphosphate (GTP), but these nucleotides were far less effective than ATP. Adenosine monophosphate (AMP), adenosine, guanosine diphosphate (GDP), guanosine monophosphate (GMP), deoxythymidine trisphosphate (dTTP), and cytosine triphosphate (CTP) were almost ineffective. The formation of inositol phosphates induced by ATP was inhibited partially by pretreatment of the cells with pertussis toxin. This toxin ADP-ribosylated a protein with a molecular mass of about 40,000. These results indicate that ATP induced the phospholipase C-mediated hydrolysis of phosphoinositides probably via P2-purinoceptors in rat aortic vascular smooth muscle cells, and suggest that a pertussis toxin-sensitive GTP-binding protein is involved at least partially in the coupling of this receptor to the phospholipase C in this cell type.
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PMID:Stimulation of phospholipase C-mediated hydrolysis of phosphoinositides by adenosine 5'-triphosphate via P2-purinoceptors in cultured rat aortic vascular smooth muscle cells. 284 65

The effect of neuropeptide Y (NPY) on adenylate cyclase activity was examined in ventricular myocytes isolated from the adult rat heart. In the presence of the phosphodiesterase inhibitor Ro 20-1724 (0.5 mM) and adenosine deaminase (5 U/ml), these intact cells accumulate cyclic AMP when stimulated by isoproterenol. NPY (10(-9) to 10(-6) M) reduced the degree of cAMP accumulation achieved by 10(-7) M isoproterenol in a dose dependend manner by 10 to maximally 48%. The IC50 value was 3 x 10(-8) M NPY. A maximal concentration (10(-6) M) of N6-phenylisopropyladenosine (PIA) decreased cAMP levels by 39%, i.e. to a similar extent. Prior treatment of the myocytes with pertussis toxin (1 microgram/ml for 6 h) increased the mean stimulated values in the presence of isoproterenol (10(-7) M) by a factor 4.1. In such cells, NPY and PIA were ineffective in antagonizing the stimulation of cAMP production by isoproterenol. These results indicate that the ventricular myocyte has receptors for NPY, similar to the A1 adenosine-receptor in that they are linked to the adenylate cyclase by an inhibitory guanylate binding protein.
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PMID:The antiadrenergic effect of neuropeptide Y on the ventricular cardiomyocyte. 285 10

Guanine nucleotides and pertussis toxin were used to investigate whether somatostatin receptors interact with the guanine nucleotide inhibitory protein (Ni) on pancreatic acinar membranes in the rat. Guanine nucleotides reduced 125I-[Tyr1]somatostatin binding to acinar membranes up to 80%, with rank order of potency being 5'-guanylyl imidodiphosphate [Gpp(NH)p] greater than GTP greater than GDP greater than GMP. Scatchard analysis revealed that the decrease in somatostatin binding caused by Gpp(NH)p was due to the decrease in the maximum binding capacity without a significant change in the binding affinity. The inhibitory effect of Gpp(NH)p was partially abolished in the absence of Mg2+. When pancreatic acini were treated with 1 microgram/ml pertussis toxin for 4 h, subsequent 125I-[Tyr1]somatostatin binding to acinar membranes was reduced. Gpp(NH)p further decreased somatostatin binding to islet-activating protein (IAP)-treated acinar membranes. Pertussis toxin treatment also abolished the inhibitory effect of somatostatin on vasoactive intestinal peptide-stimulated increase in cellular content of adenosine 3',5'-cyclic monophosphate (cAMP) in the acini. Furthermore, exposure of acini to IAP caused ADP ribosylation of a membrane protein with Mr = 41,000 in parallel to the inhibition of cAMP accumulation in acini. The present results suggest, therefore, that 1) somatostatin probably functions in the pancreas to regulate adenylate cyclase enzyme system via Ni, 2) the extent of modification of Ni is correlated with the ability of somatostatin to inhibit cAMP accumulation in acini, and 3) guanine nucleotides also inhibit somatostatin binding to its receptor.
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PMID:Coupling of guanine nucleotide inhibitory protein to somatostatin receptors on pancreatic acinar membranes. 288 15

Using modifications of the methods of Bokoch et al. (Bokoch, G.M., Katada, T., Northup, J. K., Ui, M., and Gilman, A. G. (1984) J. Biol. Chem. 259, 3560-3567) and Codina et al. (Codina, J., Hildebrandt, J. D., Sekura, R. D., Birnbaumer, M., Bryan, J., Manclark, C. R., Iyengar, R., and Birnbaumer, L. (1984) J. Biol. Chem. 259, 5871-5886), we have purified a pertussis toxin substrate with the expected characteristics of the inhibitory guanine nucleotide-binding protein (Ni) essentially to homogeneity. The purified protein consists of 3 subunits of Mr 40,000, 35,000, and less than 10,000. The Mr 40,000 band is found, upon close examination, to consist of a poorly resolved doublet. Starting with the membranes from 1,320 g of bovine forebrain we purified the protein some 100-fold with approximately 20% yield to obtain 13 mg of a greater than 95% pure protein. Chromatography on octyl-Sepharose provided efficient separation of Ni from Ns (the stimulatory guanine nucleotide-binding protein). Analytical ultracentrifugation indicates an Mr of 82,000 and a sedimentation coefficient S20,w of 5.1. The protein is able to restore opiate-mediated inhibition of adenylate cyclase to membranes prepared from NG 108-15 cells which had been treated with pertussis toxin. Bovine brain Ni has the enzymatic properties of a low Km GTPase with a turnover number of 0.3 and affinities for nucleotides in the order GppNHp greater than or equal to GTP greater than or equal to GDP much greater than ATP, CTP, UTP, and GMP. Na+ specifically stimulates the GTPase and low concentrations of Mg2+ (less than 50 microM) are inhibitory. Some Mg2+ is apparently necessary because EDTA, but not EGTA, abolishes the GTPase activity.
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PMID:The inhibitory guanine nucleotide-binding protein (Ni) purified from bovine brain is a high affinity GTPase. 298 5

The tridecapeptide, neurotensin, inhibited prostaglandin E1-stimulated cyclic AMP production in intact plated neuroblastoma N1E115 cells. The peptide effect was concentration dependent (EC50 = 2 nM) and maximal inhibition reached 55% with 100 nM neurotensin. Acetyl neurotensin (8-13) was as active as neurotensin whereas neurotensins (1-8), (1-12), and (10-13) were barely active in inhibiting cyclic AMP production, thus showing the requirement of the carboxy terminal hexapeptide sequence of neurotensin for biological activity. The inhibitory effect of neurotensin on cyclic AMP production was largely prevented by pretreatment of N1E115 cells with islet-activating protein (pertussis toxin). In contrast, pertussis toxin did not inhibit neurotensin-stimulated cyclic GMP production in neuroblastoma cells. In cell membranes, the toxin promoted the selective ADP-ribosylation of a single protein having the same molecular weight (41,000) as the alpha-subunit of Ni, the inhibitory regulatory protein of adenylate cyclase. In membranes prepared from N1E115 cells, monoiodo[125I-Tyr3]neurotensin bound to a single population of receptors characterized, at 25 degrees and in the absence of monovalent cations and guanyl nucleotides, by a dissociation constant (Kd) of 56 pM and a maximal binding capacity (Bm) of 30 fmol/mg of protein. Na+ (10-100 mM) and GTP (0.1-100 microM) inhibited neurotensin binding in a concentration-dependent manner. At 100 mM Na+ and 100 microM GTP, receptor affinity was decreased by 5- and 2-fold, respectively. Li+ and K+ were less effective than Na+, and the effect of GTP was shared by GDP and guanyl-5'-yl-imidodiphosphate, but not by GMP, ATP, ADP, or adenyl-5'-yl-imidodiphosphate. It is concluded that in N1E115 cells, neurotensin attenuates cyclic AMP production by exerting an inhibitory effect on adenylate cyclase through an interaction of the peptide receptors with the regulatory GTP-binding protein Ni.
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PMID:Neurotensin-mediated inhibition of cyclic AMP formation in neuroblastoma N1E115 cells: involvement of the inhibitory GTP-binding component of adenylate cyclase. 301 77

The nonhydrolyzable GTP analogue guanosine 5'-(beta, gamma-imido)triphosphate (GMP-PNP) produced an ATP-dependent but Ca2+-independent stimulation of [3H]norepinephrine release from permeabilized chromaffin cells. This stimulation of secretion was 25-35% of the secretion induced by 10 microM Ca2+. A similar Ca2+-independent stimulation was produced by other non-hydrolyzable GTP analogues. No effect was seen with a variety of other nucleotides, including GTP. The GMP-PNP effect was specifically inhibited by low concentrations of guanine nucleotides. Addition of cAMP did not mimic the Ca2+-independent GMP-PNP effect, but did slightly enhance Ca2+-dependent secretion. Pretreatment with pertussis toxin had no effect on Ca2+-dependent secretion or on the GMP-PNP effect. There was no detectable diglyceride or inositol phosphate produced during GMP-PNP treatment, and addition of diglyceride and inositol trisphosphate did not induce secretion. Guanosine 5'-(beta-thio)diphosphate (GDP-beta-S), in addition to its ability to inhibit the GMP-PNP effect, partially inhibited Ca2+-dependent secretion. At 10 microM free Ca2+, the effects of GMP-PNP and Ca2+ were nonadditive. In fact, secretion in the presence of both GMP-PNP and 10 microM Ca2+ was slightly less than secretion due to Ca2+ alone. These data suggest that a guanine nucleotide-dependent process interacts in some way with one or more components of the normal Ca2+-dependent secretory pathway. However, it may not be an intrinsic part of the mechanism underlying Ca2+-dependent secretion.
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PMID:Guanine nucleotide effects on catecholamine secretion from digitonin-permeabilized adrenal chromaffin cells. 301 21

The stimulation of gonadotropin release from pituitary cell cultures by GnRH has been linked to inositol phospholipid breakdown to diacylglycerols and subsequent activation of protein kinase C as well as Ca2+ mobilization. In order to examine the means of receptor coupling to a phospholipase C-type reaction, we evaluated the role of guanine nucleotides in inositol phospholipid breakdown. In these studies ATP (50 microM) was used for cell permeabilization to allow guanine nucleotides access to the intracellular compartment. Under these conditions GTP and the GTP analog, guanylylimidodiphosphate (GMP-PNP), stimulated a time- and dose-dependent increase in LH release and inositol phosphate accumulation. These actions of GTP and GMP-PNP were not observed unless ATP was included in the treatment media. Other closely related nucleotides and nucleosides alone, or in the presence of ATP, did not elevate LH release above basal levels. We also evaluated the actions of pertussis toxin and cholera toxin on mediating the effect of GTP, GMP-PNP, and GnRH on LH release and inositol phosphate accumulation. After treatment with these agents, no changes were observed in the ability of GnRH, GTP, or GMP-PNP to stimulate either LH release or inositol phosphate accumulation. The additional observation that GnRH-, GTP-, or GMP-PNP-stimulated LH release and inositol phosphate accumulation were blocked by a potent GnRH antagonist suggests that a G protein is functionally associated with the GnRH receptor recognition site.
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PMID:Stimulation of luteinizing hormone (LH) release and phospholipid breakdown by guanosine triphosphate in permeabilized pituitary gonadotropes: antagonist action suggests association of a G protein and gonadotropin-releasing hormone receptor. 302 16

Evidence is shown that protein kinase C is the major kinase which can phosphorylate histone H-1 in a membrane fraction prepared from rabbit peritoneal neutrophils. Addition of phorbol-12-myristate-13-acetate (PMA) (0.1 microgram/ml) or guanosine-5'-(3-O-thio)triphosphate (GTP gamma S) (10 microM) to the membrane fraction results in an increase of the phosphorylation of histone H-1. To achieve this effect, calcium (20 microM) is required for GTP gamma S but not for PMA. The effect of GTP gamma S, but not PMA is inhibited in membranes obtained from cells pretreated with pertussis toxin. The kinase activity is also enhanced by treatment of the membrane with 10 microM of GppNHp or GTP but not with GDP, GMP, cGMP, ATP, ADP, AMP and cAMP. This is the first direct evidence that a GTP binding protein is involved in the activation of membrane associated protein kinase C.
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PMID:Regulation of membrane associated protein kinase C activity by guanine nucleotide in rabbit peritoneal neutrophils. 302 4

Adenylate cyclase activity was identified in membranes isolated from bovine lens fiber cells. Basal activity, in the presence of microM Ca2+ was stimulated by either sodium fluoride, guanosine 5'-[alpha,beta-imido]triphosphate (Gpp(NH)p), or forskolin; ethylene glycolbis(2-aminoethylether) tetraacetic acid (EGTA) markedly inhibited both the basal activity and the extent of stimulation by these agents. Exogenous calmodulin enhanced the Ca2+-dependent stimulation of adenylate cyclase activity. In the presence of optimal concentrations of Ca2+ plus calmodulin, adenylate cyclase activity was approximately 15 times greater than that in the presence of EGTA. Adenylate cyclase activity was not stimulated by a number of potential agonists that included carbachol, serotonin, prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), adenosine, isoproterenol epinephrine, dopamine, and phenylephrine. The presence of the Ns and Ni guanine nucleotide regulatory complexes was indicated by two observations: Cholera toxin catalyzed the adenosine diphosphate (ADP) ribosylation of a number of lens membrane proteins, including a 46,500-dalton component (likely the alpha-subunit of Ns), and Pertussis toxin catalyzed the ADP ribosylation of a single 41,000-dalton lens membrane component (likely the alpha-subunit of Ni). However, that Gpp(NH)p did not inhibit either the forskolin-activated or the calmodulin-activated adenylate cyclase activities does not indicate a role for Ni in regulating this enzyme. Both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) phosphodiesterase activities were identified in a supernate fraction derived from bovine lens. The cAMP phosphodiesterase activity appeared to be predominantly the low Km form of the enzyme. The cGMP phosphodiesterase activity, which was Ca2+-dependent, was partly inhibited maximally by 7 microM R24571, indicating its probable calmodulin dependence.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of lens cyclic nucleotide metabolism by Ca2+ plus calmodulin. 303 38


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