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 nucleotide-binding regulatory protein stimulation of adenylyl cyclase has been shown to be an important second messenger system for many processes, including mechanical hyperalgesia. Recently, interactions between guanine nucleotide-binding regulatory protein subunits and adenylyl cyclase affecting the level of cyclic adenosine 3',5'-monophosphate accumulation have been demonstrated. In this study we evaluated such an interaction by measuring paw-withdrawal thresholds to mechanical stimuli in Sprague-Dawley rats in the presence of two direct-acting hyperalgesic agents, prostaglandin E2 and the adenosine A2-agonist, CGS21680. The effects of two agents expected to liberate inhibitory guanine nucleotide-binding regulatory protein subunits were also studied: [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (a mu-opioid receptor agonist) and N6-cyclopentyladenosine (an A1-adenosine agonist). Injection of [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin immediately before prostaglandin E2 or CGS21680 significantly attenuated the hyperalgesia subsequently induced by these agents, i.e. the sensitivity to these hyperalgesic agents was decreased. On the other hand, injection of [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin 5 min after prostaglandin E2 or CGS21680 significantly enhanced the hyperalgesia observed. Injection of the adenosine A1-agonist N6-cyclopentyladenosine immediately before and 5 min after prostaglandin E2 or CGS21680 had a similar effect to [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin. The decrease in sensitivity to prostaglandin E2- and CGS21680-induced hyperalgesia by preadministration of [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin or N6-cyclopentyladenosine and the enhancement by postadministration were all reversed by pertussis toxin, an inhibitor of inhibitory guanine nucleotide-binding regulatory protein, suggesting the involvement of an inhibitory guanine nucleotide-binding regulatory protein.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mu-opioid agonist enhancement of prostaglandin-induced hyperalgesia in the rat: a G-protein beta gamma subunit-mediated effect? 747 99

In rat pituitary GH3 cells Ca2+ current through L-type channels is reduced by somatostatin. This modulation of channel activity by somatostatin receptors is mediated by a guanine nucleotide-binding regulatory protein (G protein). It is sensitive to pertussis toxin, indicating the involvement of a G(o)- or Gi-type G protein in this pathway. The identity of this G protein was determined by suppressing the expression of endogenous G proteins individually via intranuclear injection of antisense oligonucleotides. This method was applied to GH3 cells to screen several G protein alpha, beta and gamma subunits for their roles in the defined signal transduction pathway. The loss of somatostatin's modulating activity on the voltage-dependent Ca2+ channel after oligonucleotide injection revealed the involvement of G(o) alpha 2 beta 1 gamma 3 to the exclusion of other closely related subtypes.
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PMID:Somatostatin modulates voltage-dependent Ca2+ channels in GH3 cells via a specific G(o) splice variant. 758 46

The role of temperature and testicular descent in postnatal appearance of inhibitory guanine nucleotide-binding regulatory protein (G(i)) function was studied in the rat testis. Dispersed testicular cells of 5-day-old rats were incubated for 24 h at 32 or 37 C, then for another 24 h at the same temperatures in the presence and absence of pertussis toxin (PT; 100 micrograms/liter), and finally for a third 24-h period with cholera toxin (CT; 500 ng/liter) with or without PT. At both temperatures, PT treatment significantly (P < 0.05) increased the CT-stimulated cAMP output, but had no effect on basal cAMP production. When testosterone (T) production, as an indicator of Leydig cell function, was measured in the same incubation, CT-stimulated T production was greater at 32 C, but PT had no effect at either temperature. A similar finding was made when hCG (10 micrograms/liter), instead of CT, was used as the stimulus of T production. Hence, a functional G(i) protein is present in seminiferous tubules of 5-day-old testes cultured for 3 days at 32 and 37 C, but not in Leydig cells. We then examined the effects of longer exposure of 5-day-old testes to the two temperatures. After culture for 7 days with 0.1 microgram/liter ovine LH, the presence of PT at 32 C significantly (P < 0.01) enhanced CT-stimulated T production during the last 24 h of culture, but the PT effect was not observed when the culture was carried out at 37 C. Hence, G(i)-mediated modulation of Leydig cell function appears to require several days of induction at the lower temperature of 32 C. As the postnatal descent also changes the ambient testicular temperature, we next studied whether this event alters the G(i) protein function of Leydig cells. Five-day-old rats were rendered bilaterally cryptorchid or sham operated, and studied after 12 days. Testis weights did not differ between the abdominal and scrotal testes. In contrast, the basal and hCG-stimulated rates of T production were significantly (P < 0.01-0.05) higher in the scrotal testes. When dispersed cells of the scrotal and abdominal testes were incubated for 24 h at 37 C in the presence of CT with or without PT, enhancement of T production by PT was only observed in cells of the scrotal testes.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:A novel role for testicular descent; temperature-dependent induction of pertussis toxin-sensitive Gi protein function in postnatal rat Leydig cells. 766 86

The endothelin (ET) family of peptides acts via two subtypes of guanine nucleotide-binding regulatory protein (G protein)-coupled receptors termed ETA and ETB. ET-1 stimulated cAMP formation in Chinese hamster ovary (CHO) cells stably expressing human wild-type ETA (CHO/hETA cells) while it inhibited cAMP formation in CHO cells expressing human wild-type ETB (CHO/hETB cells), and pharmacological evidence indicated that the opposite effects were due to the selective coupling of each receptor subtype with G alpha s/G alpha i. To find out a receptor domain(s) that determined the selective coupling, a series of chimeric receptors between hETA and hETB was expressed on CHO cells, and the effect of ET-1 on cAMP formation in each cell line was tested. hETA with the replacement of second and/or third intracellular loop (ICLII and/or -III) to the corresponding region(s) of hETB failed to transmit the stimulatory effect of ET-1. hETB with the replacement of ICLIII to the corresponding region of hETA failed to transmit the inhibitory effect of ET-1. A chimeric receptor with ICLII of hETB and with ICLIII of hETA failed to transmit both effects. In cells expressing chimeric receptors with ICLII of hETA and with ICLIII of hETB, ET-1 inhibited cAMP formation while it stimulated cAMP formation when cells were pretreated with pertussis toxin. These results indicated the roles of ICLII and -III of hETR as a major determinant of the selective coupling of hETA and hETB with G alpha s/G alpha i, respectively. We also demonstrated that each receptor subtype expressed on the same cell could work independently, i.e. for hETA to activate G alpha s and for hETB to activate G alpha i, resulting in dose-dependent dual effects of ET-1 on cAMP formation.
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PMID:Structural basis of G protein specificity of human endothelin receptors. A study with endothelinA/B chimeras. 773 Mar 10

The ontogeny of function and mRNA expression of the inhibitory guanine nucleotide-binding regulatory protein (Gi) was studied in the rat testis. Dispersed testis cells of animals aged 8, 15, 20 and 30 days were cultured with or without 100 micrograms/l pertussis toxin (PT) for 24 h. The cells were then cultured for another 24 h with medium only, cholera toxin (CT), PT, or their combination, and the amount of testosterone and cAMP production was measured. PT preincubation increased CT-stimulated cAMP production at all ages, thus indicating the presence of a functional Gi-protein in the postnatal testis. However, when testosterone production was measured, the enhancing effect of PT was absent at the age of 8 days only, indicating that Leydig cells at this age did not have functional Gi-protein. We then cultured 2-day-old and 8-11-day-old testis cells, after 24 h pretreatment with PT, in the presence of ovine follicle-stimulating hormone (FSH) (1 mg/l). The FSH-stimulated cAMP production was enhanced at both ages, thus indicating the presence of a functional Gi-protein in neonatal Sertoli cells. In Northern blot analyses, fetal and postnatal testis tissue had very similar levels of G alpha i2 and G alpha i3 mRNAs; the mRNA level of Gi1 in Northern blots remained low compared to those of Gi alpha 2 and Gi alpha 3. In conclusion, the Gi protein appears in the developing rat testis in utero but the activity first seems to be confined to non-Leydig cells including the Sertoli cell. In Leydig cells, the functional Gi-protein appears between days 8-15 post partum. This finding may be related to the fact that the fetal-neonatal population of Leydig cells possesses a high steroidogenic capacity and an apparent lack of the ability to respond to high gonadotropic stimulation with LH receptor down-regulation and steroidogenic enzyme desensitization.
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PMID:Ontogeny of the inhibitory guanine nucleotide-binding regulatory protein in the rat testis: mRNA expression and modulation of LH and FSH action. 792 74

In guanine nucleotide-binding regulatory protein- (G protein) coupled receptors, an amphipathic alpha-helix has been postulated to be the common structural determinant in the NH2- and COOH-terminal portions of the third intracellular loop representing the major interaction site with the G proteins. Here we assessed the ability of six peptides derived from these sites of the human dopamine D1-, D2-, and beta 1-adrenergic receptors to either activate G proteins directly or to uncouple the activity of their respective receptors in a native membrane environment. In addition, the cross-reactivity was analyzed. Nonspecific effects occurring at high concentrations were differentiated from G protein-specific effects. The peptide D2N derived from the NH2-terminal part of the third intracellular loop of the dopamine D2 receptor was the only one capable of specifically reversing the action of its receptor, the dopamine-mediated inhibition of the adenylyl cyclase. Furthermore, only D2N stimulated pertussis toxin-sensitive G proteins. However, D2N as the only peptide exhibiting specific effects did not exhibit the predicted amphipathic alpha-helix observed for mastoparan (Higashijima, T., Burnier, J., and Ross, E. M. (1990) J. Biol. Chem. 265, 14176-14186) as demonstrated by circular dichroism spectroscopy. In contrast, a peptide for which a certain degree of helicality was verified spectroscopically (D1C) was neither active in GTPase and adenylyl cyclase determinations, nor did it block the receptor-mediated cyclase activation. Hence, the amphipathic alpha-helix does not represent the main structural determinant for the receptor-G protein interaction site.
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PMID:Amphipathic alpha-helical structure does not predict the ability of receptor-derived synthetic peptides to interact with guanine nucleotide-binding regulatory proteins. 838 21

In rat pituitary GH3 cells, thyrotropin-releasing hormone (TRH) and other secretion-stimulating hormones trigger an increase in the cytosolic Ca2+ concentration by two mechanisms. Ca2+ is released from intracellular stores in response to inositol 1,4,5-trisphosphate and can enter the cell through voltage-dependent L-type Ca2+ channels. Stimulation of these channels is sensitive to pertussis toxin, indicating that a pertussis toxin-sensitive heterotrimeric guanine nucleotide-binding regulatory protein (G protein) is involved in functional coupling of the receptor to the Ca2+ channel. We identified the G protein involved in the stimulatory effect of TRH on the Ca2+ channel by type-selective suppression of G-protein synthesis. Antisense oligonucleotides were microinjected into GH3 cell nuclei, and 48 h after injection the TRH effect was tested. Whereas antisense oligonucleotides hybridizing to the mRNA of G(o) or Gi1 alpha-subunit sequences did not affect stimulation by TRH, oligonucleotides suppressing the expression of the Gi2 alpha subunit abolished this effect, and oligonucleotides directed against the mRNA of the Gi3 alpha subunit had less effect. The requirement of a concurrent inositol phospholipid degradation and subsequent protein kinase C (PKC) activation for the TRH effect on Ca(2+)-channel activity was demonstrated by inhibitory effects of antisense oligonucleotides directed against Gq/G11/Gz alpha-subunit sequences and treatment of GH3 cells with PKC inhibitors, respectively. Our results suggest that TRH elevates the cytosolic Ca2+ concentration in GH3 cells transiently via Ca2+ release from internal stores, followed by a phase of sustained Ca2+ influx through voltage-dependent Ca2+ channels stimulated by the concerted action of Gi2 (and Gi3) plus PKC.
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PMID:Gi2 and protein kinase C are required for thyrotropin-releasing hormone-induced stimulation of voltage-dependent Ca2+ channels in rat pituitary GH3 cells. 839 94

It has been established that LPS, the major constituent of the outer membrane of gram negative bacteria, stimulates macrophages to produce numerous inflammatory mediators, including TNF-alpha and nitric oxide (NO). Both TNF-alpha and NO are important in the macrophage-mediated cytotoxicity against invading microorganisms and tumor cells. Although many LPS-dependent immune responses have been well characterized phenomenologically, the precise signal transduction pathways in LPS-induced macrophage activation are not clear. We reported that 1) pretreatment of C3HeB/FeJ mouse peritoneal macrophages with pertussis toxin (PT) markedly enhanced LPS-induced TNF-alpha production but inhibited LPS-dependent NO production under the same conditions; 2) kinetics of the PT effects on these LPS-responses were correlated with PT-mediated ADP-ribosylation of a 41-kDa protein(s); and 3) PT pretreatment did not correct the refractory states of C3H/HeJ macrophages to wild type smooth-LPS. These results suggest that LPS stimulates TNF-alpha and NO production in mouse peritoneal macrophages through different biochemical pathways, and that the signal transduction for both pathways is regulated by a PT-sensitive factor. It is possible that this factor is a guanine nucleotide-binding regulatory protein(s). Finally our data indicate that it is unlikely that the defect of the C3H/HeJ macrophages in response to LPS is at the level of this PT-sensitive factor.
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PMID:Pertussis toxin-sensitive factor differentially regulates lipopolysaccharide-induced tumor necrosis factor-alpha and nitric oxide production in mouse peritoneal macrophages. 842 28

Hamster tracheal epithelial cell cultures were used to investigate muscarinic regulation of high-molecular-weight glycoconjugate (HMWG) secretion by airway goblet cells. HMWG were radiolabeled with N-acetyl-D-[1-(3)H]glucosamine, precipitated with trichloroacetic acid and phosphotungstic acid, and counted by liquid scintillation. Carbachol (100 microM) increased HMWG secretion (166.6 +/- 18.7%, P < 0.001, n = 20), and this response was blocked by the muscarinic receptor antagonist atropine. Ca2+ may not be essential for carbachol response since 1) carbachol-activated secretion was not inhibited by chelating extracellular Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) or by reducing both extracellular and intracellular Ca2+ with BAPTA-acetoxymethyl ester in low-Ca2+ medium; 2) the carbachol response was only partially blocked in low-Ca2+ medium; and 3) calcium ionophore did not stimulate HMWG secretion. However, carbachol-stimulated secretion was abolished by pertussis toxin (PTX), indicating the involvement of a PTX-sensitive guanine nucleotide-binding regulatory protein (G protein), and by the protein kinase C (PKC) inhibitor chelerythrine chloride. Furthermore, carbachol-stimulated secretion was not inhibited by overnight incubation with phorbol 12-myristate 13-acetate. In conclusion, carbachol-stimulated secretion of HMWG appears to be coupled to a PTX-sensitive G protein and requires the activation of a phorbol ester-insensitive PKC isoform.
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PMID:Muscarinic-induced mucin secretion and intracellular signaling by hamster tracheal goblet cells. 912 73

Leukotriene B4 (LTB4) is a potent chemoattractant derived from arachidonic acid. When cDNAs for LTB4 receptor (BLT) were cloned it was found that they belong to a guanine nucleotide-binding regulatory protein (G-protein)-coupled receptor superfamily. However, purification of BLT from inflammatory cells and reconstitution with various types of G-proteins have not been successful. In the present study, BLT from porcine leukocytes was solubilized, separated from associated G-proteins by Ricinus communis agglutinin (RCA) 120 chromatography, and reconstituted with several endogenous and exogenous G-proteins, in combination with the fraction which contained endogenous phospholipids and Gbeta gamma. Kinetic studies of LTB4 were performed to determine the association with G-proteins. A partially purified BLT fraction (retained on an RCA120 column) free of G-proteins showed a lower affinity for LTB4 (Kd = 500 nm), but reconstitution of the BLT fraction with a G-protein-rich fraction (flow-through of an RCA column) increased the affinity for LTB4 10-fold (Kd = 50 nm). The partially purified BLT fraction was also reconstituted with exogenous G-proteins such as a heterotrimeric Gi2 purified from bovine brain or recombinant alpha subunits of Gi1, Gi2, Gi3, and Go expressed in Spodoptera frugiperda-9 cells. These increases in LTB4 bindings demonstrate that the BLT of porcine leukocytes can interact with pertussis toxin-sensitive G-proteins in vitro. The method is useful for the purification and reconstitution of other, as yet unisolated, G-protein-coupled receptors.
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PMID:Characterization of the leukotriene B4 receptor in porcine leukocytes. Separation and reconstitution with heterotrimeric GTP-binding proteins. 991 22


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