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

alpha 2-Adrenergic receptor (alpha 2-AR) subtypes couple to pertussis toxin (PT)-sensitive G-proteins to elicit both stimulatory and inhibitory cell responses. Signal specificity may be generated by the ability of the receptor subtypes to "recognize" distinct G-proteins with different affinity. To address this issue we stably expressed three alpha 2-AR subtypes, RNG alpha 2 (alpha 2B-AR), RG10 (alpha 2C-AR), and RG20 (alpha 2D-AR), in NIH-3T3 fibroblasts, which express two PT-sensitive G-proteins (Gi alpha 2, Gi alpha 3), and analyzed receptor/G-protein interactions by determining: 1) functional coupling to adenylylcyclase and 2) the ability of the receptors to exist in a high affinity state for agonist. In alpha 2D-AR transfectants expressing 200 or 2,200 fmol of receptor/mg of protein, epinephrine (10 microM) inhibited forskolin-induced elevation of cellular cAMP by 26 +/- 4.8% and 72 +/- 6.2%, respectively. Similar results were obtained in alpha 2B-AR transfectants. However, in alpha 2C-AR transfectants (200 fmol/mg) the forskolin-induced elevation of cellular cAMP was not altered by agonist treatment. In alpha 2C-AR transfectants expressing higher receptor densities (650-1,200 fmol/mg), epinephrine inhibited the effect of forskolin by 30 +/- 3.2%. This difference in functional coupling among the alpha 2-AR subtypes is reflected at the receptor/G-protein interface. In membrane preparations of alpha 2B and alpha 2D-AR but not alpha 2C-AR transfectants, agonist competition curves were biphasic, indicating high and low affinity states of the receptor for agonist. The high affinity state was guanyl-5'-yl imidodiphosphate- and PT-sensitive, indicative of receptor/G-protein coupling. These data suggest that the alpha 2C-AR differs from the alpha 2B and alpha 2D-AR subtypes in its ability to recognize PT-sensitive G-proteins expressed in NIH-3T3 fibroblasts. The alpha 2C-AR may couple preferentially to PT-sensitive G-proteins (Gi1, Go1,2) not expressed in NIH-3T3 fibroblasts and thereby elicit different cellular responses.
 ...
PMID:Factors determining the specificity of signal transduction by guanine nucleotide-binding protein-coupled receptors. I. Coupling of alpha 2-adrenergic receptor subtypes to distinct G-proteins. 134 6

Organotypic cultures of fetal mouse spinal cord-ganglion explants (2-4 weeks in vitro) contain forskolin-stimulated adenylate cyclase (AC) activity that is inhibited by levorphanol and other opioid agonists in a dose-dependent manner. Inhibition by levorphanol no longer occurs if sodium is omitted from the incubation and the levorphanol inhibition is blocked by the opioid antagonist, naloxone. These findings together with the ineffectiveness of dextrorphan indicate that the opioid inhibition of forskolin-stimulated AC is receptor mediated. Both the delta- and kappa-receptor subtypes appear to be involved since the selective delta-opioid agonist, [D-Pen2, D-Pen5]enkephalin, and the selective kappa-opioid agonist, t-3,4-dichloro-N-methyl-N[2-(1-pyrrolidinyl)cyclohexyl]-benzene acetamide (U-50,488H) are both effective at nanomolar concentrations. In contrast, the selective mu-opioid agonist, Tyr-D-Ala-Gly-N-MePhe-Gly-ol, has no significant effect even at micromolar concentrations. Both cord and ganglion components of the explants contain opioid-sensitive AC. Forskolin-stimulated AC of the explants is also inhibited by serotonin and carbachol. The serotonin effect appears to be mediated by 5-HT1A receptors, based on relative agonist and antagonist selectivity. Chronic exposure of cultures to morphine results in enhanced basal and forskolin-stimulated AC as well as attenuation of opioid-inhibition of AC assayed in the presence of forskolin; treatment of explants with pertussis toxin causes similar changes in the AC system. The inhibitory effect of serotonin is also attenuated by the pertussis toxin treatment. Basal AC activity of the explants (assayed without forskolin present) is stimulated to a small but significant extent by opioids and by serotonin. The opioid stimulatory effect is markedly enhanced following either morphine or pertussis toxin treatment of the explants. The attenuation of opioid- and serotonin-inhibition of AC produced by chronic exposure to pertussis toxin and the attenuation of opioid inhibition produced by exposure to morphine are consonant with the attenuation of opioid and monoaminergic depression of sensory evoked dorsal horn network responses after similar chronic treatments. It is proposed that the inhibitory effects of opioids and serotonin on these neurons are mediated by receptors that are negatively coupled via a pertussis toxin sensitive Gi protein to AC. Furthermore, alterations of AC with chronic morphine treatment may be involved in the development of physiologic tolerance to opioids.
 ...
PMID:Modulation of adenylate cyclase activity of mouse spinal cord-ganglion explants by opioids, serotonin and pertussis toxin. 337 Apr 65

Modulation of alpha 2-adrenergic and opioid neurotransmission may contribute to ethanol intoxication, tolerance, and physical dependence. We showed previously that ethanol increased the expression of functional delta-opioid receptors in NG108-15 cells (Charness, M. E., Querimit, L. A., and Diamond, I. (1986) J. Biol. Chem. 261, 3164-3169). Here we report that long-term (2 days) treatment of NG108-15 cells with ethanol increased the binding of the alpha 2-adrenergic receptor (alpha 2AR) antagonist [3H]rauwolscine and the muscarinic acetylcholine receptor (mAChR) antagonist [3H]quinuclidinyl benzilate by 2.8- and 1.4-fold, respectively. Increased receptor expression was associated with a proportionate increase in the potency of oxymetazoline and carbachol in inhibiting cAMP accumulation. Ethanol did not change the expression of G alpha i2 and reduced levels of G alpha s. Pertussis toxin pretreatment did not prevent the ethanol-induced increase in alpha 2AR, mAChR, and delta-opioid receptor expression. Ethanol caused a large (3.6-fold), dose-dependent increase in the abundance of alpha 2BAR mRNA (rat cDNA probe RNG, 4.1-kb transcript). Ethanol-induced increases in alpha 2BAR and alpha 2CAR (rat probe RG10, 2.5-kb transcript) mRNAs were first detected after 6 h of exposure to 100 mM ethanol, became maximal after 24 h, and persisted for up to 5 days. In contrast, ethanol caused only a small (1.3-fold) increase in the abundance of hm4 mAChR mRNA and did not change levels of G alpha i2 and G alpha s mRNAs. Our data indicate that clinically attainable concentrations of ethanol regulate alpha 2AR gene expression within the time frame of a single session of drinking.
 ...
PMID:Ethanol differentially increases alpha 2-adrenergic and muscarinic acetylcholine receptor gene expression in NG108-15 cells. 822 69

A C6 glioma cell line stably transfected with the human kappa opioid receptor (kappaOR) was used to characterize receptor binding and G protein activation via the kappaOR by a comprehensive series of opioid ligands. The ligand-binding affinity for [3H]5alpha,7alpha, 8beta(-)-N-methyl-N-(7-Cl-pyrrolidinyl)-1-oxaspiro(4, 5)dec-8-yl)benzene acetamide (U69593) was similar to that observed in monkey brain membranes and was 10-fold lower in the presence of sodium and GDP. Both peptide and nonpeptide agonists maximally stimulated [35S]GTPgammaS binding. The stimulation of [35S]GTPgammaS binding was blocked by pretreatment of cells with pertussis toxin. Partial stimulation of [35S]GTPgammaS binding via the kappaOR was observed for several ligands that are antagonists at the mu opioid receptor, suggesting an additional mechanism of drug action. The ability of isomers of tifluadom and levallorphan to stimulate [35S]GTPgammaS binding indicates that the chiral carbon of levallorphan, a benzomorphan derivative, imparts a greater degree of stereoselectivity than does the chiral carbon in the benzodiazepine derivative tifluadom. In addition, (-)tifluadom, the less potent isomer of tifluadom, which is also a gamma-aminobutyric acidA receptor agonist, stimulated [35S]GTPgammaS binding. In contrast, d-pentazocine, (+)SKF10047, (+)cyclazocine, and d-ethylketocyclazocine displayed no agonist activity. kappaOR-selective antagonist norbinaltorphimine competitively inhibited the stimulation of [35S]GTPgammaS binding by the active isomers of ethylketocyclazocine, cyclazocine, and nalorphine to the same degree, indicating that all three ligands are eliciting an effect via the kappaOR. The results suggest that these cells express a homogeneous population of kappaOR, and that their [35S]GTPgammaS-binding properties make them an excellent means to assess kappaOR efficacy.
 ...
PMID:Opioid efficacy in a C6 glioma cell line stably expressing the human kappa opioid receptor. 991 95

The aim of this paper is to study the influence of salmon calcitonin (SCT) on opioid analgesia when opioid transduction pathways are functionally uncoupled from Gi/o proteins by treatment with pertussis toxin (PTX). The antinociceptive effect of morphine and three selective opioid agonists, [D-Ala2,N-Me-Phe2,Gly5-ol]enkephalin (DAMGO) (OP(3-mu receptor agonist), [D-Pen2.5]-enkephalin (OP-1-delta receptor agonist) and trans-( +/- )-3,4-dichloro-N-methyl-N-[2-1(-pyrrolidinyl)-cyclohexyl]-benzene-acetam ide methane sulfonate (U-50, 488H) (OP1-kappareceptor agonist) was evaluated, using the tail flick test, in mice treated with PTX or with PTX and SCT. PTX blocked the antinociceptive effect of the opioids, being the antinociception similar in control animals and in mice treated with PTX and SCT. Thus, SCT prevents the effect of the blockade of Gi/o-proteins. From this it could be suggested that calcitonin activates alternative antinociceptive mechanisms that are not dependent on Gi/o-proteins.
 ...
PMID:Calcitonin reverts pertussis toxin blockade of the opioid analgesia in mice. 1051 87

In the rat proximal tubule, the alpha(2B)-adrenergic receptor (alpha(2B)-AR) enhances Na(+) reabsorption by increasing the activity of Na(+)/H(+) exchanger isoform NHE3. The mechanisms involved are unclear, and inhibition of cAMP production remains controversial. In this study, we reinvestigated alpha(2B)-AR signaling pathways using rat proximal tubule cells (PTC) in primary culture and LLC-PK(1) cells permanently transfected with the RNG gene (rat nonglycosylated alpha(2)-AR). Binding experiments indicated that PTC express substantial amounts of alpha(2B)-AR (130 fmol/mg protein), and only RNG transcripts were detected. In both cell types, the alpha(2B)-AR is coupled to G protein, and its stimulation by dexmedetomidine, but not by UK-14304, provoked a significant inhibition of the accumulation of cAMP induced by forskolin or parathyroid hormone. Exposure to alpha(2)-agonists increased arachidonic acid release and caused extracellular signal-regulated kinase (ERK)1/2 phosphorylation, which correlated with enhanced mitogen-activated protein kinse (MAPK) activity and nuclear translocation. MAPK phosphorylation was blunted by pertussis toxin but not by protein kinase C desensitization, and it coincided with transient phosphorylation of Shc. Finally, treatment with UK-14304 accelerated cell growth. Further studies will be necessary to clarify the precise mechanism of MAPK activation, but the present data suggest that alpha(2B)-AR may play a positive role during tubular regeneration.
 ...
PMID:alpha(2B)-Adrenergic receptors activate MAPK and modulate proliferation of primary cultured proximal tubule cells. 1193 5

At the neuromuscular junction, ATP is co-released with the neurotransmitter acetylcholine (ACh) and once in the synaptic space, it is degraded to the presynaptically active metabolite adenosine. Intracellular recordings were performed on diaphragm fibers of CF1 mice to determine the action of extracellular ATP (100 muM) and the slowly hydrolysable ATP analog 5'-adenylylimidodiphosphate lithium (betagamma-imido ATP) (30 muM) on miniature end-plate potential (MEPP) frequency. We found that application of ATP and betagamma-imido ATP decreased spontaneous secretion by 45.3% and 55.9% respectively. 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX), a selective A(1) adenosine receptor antagonist and alpha,beta-methylene ADP sodium salt (alphabeta-MeADP), which is an inhibitor of ecto-5'-nucleotidase, did not prevent the inhibitory effect of ATP, demonstrating that the nucleotide is able to modulate spontaneous ACh release through a mechanism independent of the action of adenosine. Blockade of Ca(2+) channels by both, Cd(2+) or the combined application of nitrendipine and omega-conotoxin GVIA (omega-CgTx) (L-type and N-type Ca(2+) channel antagonists, respectively) prevented the effect of betagamma-imido ATP, indicating that the nucleotide modulates Ca(2+) influx through the voltage-dependent Ca(2+) channels related to spontaneous secretion. betagamma-Imido ATP-induced modulation was antagonized by the non-specific P2 receptor antagonist suramin and the P2Y receptor antagonist 1-amino-4-[[4-[[4-chloro-6-[[3(or4)-sulfophenyl] amino]-1,3,5-triazin-2-yl]amino]-3-sulfophenyl] amino]-9,10-dihydro-9,10-dioxo-2-anthracenesulfonic acid (reactive blue-2), but not by pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt (PPADS), which has a preferential antagonist effect on P2X receptors. Pertussis toxin and N-ethylmaleimide (NEM), which are blockers of G(i/o) proteins, prevented the action of the nucleotide, suggesting that the effect is mediated by P2Y receptors coupled to G(i/o) proteins. The protein kinase C (PKC) antagonist chelerythrine and the calmodulin antagonist N-(6-aminohexil)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) occluded the effect of betagamma-imido ATP, while the protein kinase A (PKA) antagonist KT-5720 and the inhibitor of the calcium/calmodulin-dependent protein kinase II (CAMKII) KN-62 failed to do so. betagamma-Imido ATP did not affect 10, 15 and 20 mM K(+)-evoked release and application of reactive blue-2 before incubation in high K(+) induced a higher asynchronous secretion. Thus, our results show that at mammalian neuromuscular junctions, ATP induces presynaptic inhibition of spontaneous ACh release due to the modulation of Ca(2+) channels related to tonic secretion through the activation of P2Y receptors coupled to G(i/o) proteins. We also demonstrated that at increasing degrees of membrane depolarization evoked by K(+), endogenously released ATP induces presynaptic inhibition as a means of preventing excessive neurotransmitter secretion.
 ...
PMID:Presynaptic inhibition of spontaneous acetylcholine release mediated by P2Y receptors at the mouse neuromuscular junction. 1684 2

We screened a chemolibrary of drug-like molecules for their ability to activate reactive oxygen species (ROS) production in murine phagocytes, and we identified 26 novel compounds with potent neutrophil activating properties. We used substructure screening, fragment-focusing, and structure-activity relationship analyses to further probe the parent library and defined at least two groups of activators of ROS production in murine neutrophils: t-butyl benzene and thiophene-2-amide-3-carboxylic ester derivatives. Further studies of the active compounds revealed 11 compounds that activated ROS production in human neutrophils, and six of these compounds also activated intercellular Ca(2+) mobilization and chemotaxis in human neutrophils. Of the latter compounds, compound 14 (1,3-benzodioxolane-5-carboxylic acid 4'-benzyloxy-3'-methoxybenzylidene-hydrazide) activated neutrophils at nanomolar concentrations, and Ca(2+) mobilization was inhibited by pertussis toxin and N-t-butoxycarbonyl-Phe-Leu-Phe-Leu-Phe (Boc-2), an antagonist of formyl peptide receptors (FPR/FPRL1). Likewise, activation by compound 14 was desensitized after N-formyl-Met-Leu-Phe pretreatment. Similar biological activities were found for compound 104 (1,3-benzodioxolane-5-carboxylic acid 3'-bromo-5'-ethoxy-4'-hydroxybenzylidene-hydrazide), an analog of compound 14. Furthermore, conformational analysis of the activators of chemotaxis and Ca(2+) mobilization showed a high degree of similarity in distances between pharmacophore points of compounds 14 and 104 with a model of FPR published by Edwards et al. (Mol Pharmacol 68:1301-1310, 2005), indicating that conformational features of the agonists identified here are structurally compatible with steric constraints of the ligand-binding pocket of the receptor. Based on these results, we conclude that compounds 14 and 104 represent novel small-molecule agonists of FPR. These studies enhance our understanding of FPR ligand/receptor interactions and structure/activity relationships of phagocyte agonists.
 ...
PMID:High-throughput screening for small-molecule activators of neutrophils: identification of novel N-formyl peptide receptor agonists. 1722 69

Monocarboxylate transporter isoform-1 (MCT1) plays an important role in the absorption of short-chain fatty acids (SCFAs) in the colon. Butyrate, a major SCFA, serves as the primary energy source for the colonic mucosa, maintains epithelial integrity, and ameliorates intestinal inflammation. Previous studies have shown substrate (butyrate)-induced upregulation of MCT1 expression and function via transcriptional mechanisms. The present studies provide evidence that short-term MCT1 regulation by substrates could be mediated via a novel nutrient sensing mechanism. Short-term regulation of MCT1 by butyrate was examined in vitro in human intestinal C2BBe1 and rat intestinal IEC-6 cells and ex vivo in rat intestinal mucosa. Effects of pectin feeding on MCT1, in vivo, were determined in rat model. Butyrate treatment (30-120 min) of C2BBe1 cells increased MCT1 function {p-(chloromercuri) benzene sulfonate (PCMBS)-sensitive [(14)C]butyrate uptake} in a pertussis toxin-sensitive manner. The effects were associated with decreased intracellular cAMP levels, increased V(max) of butyrate uptake, and GPR109A-dependent increase in apical membrane MCT1 level. Nicotinic acid, an agonist for the SCFA receptor GPR109A, also increased MCT1 function and decreased intracellular cAMP. Pectin feeding increased apical membrane MCT1 levels and nicotinate-induced transepithelial butyrate flux in rat colon. Our data provide strong evidence for substrate-induced enhancement of MCT1 surface expression and function via a novel nutrient sensing mechanism involving GPR109A as a SCFA sensor.
 ...
PMID:A novel nutrient sensing mechanism underlies substrate-induced regulation of monocarboxylate transporter-1. 2298 38