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)

Guanosine triphosphate (GTP)-binding protein subunits were studied by immunoblot analysis in particulate fractions from mature adipocytes, confluent preadipocytes, and in vitro-differentiated preadipocytes. Mature adipocytes express Gi alpha 1, Gi alpha 2, Gi alpha 3, Go alpha, Gq/11 alpha, G13 alpha and the long and short isoforms of Gs alpha, but no Gz alpha or G12 alpha. Confluent and differentiated preadipocytes differ in having a higher content of Gi alpha 3 and G13 alpha and expressing G12 alpha. In contrast, they lack Gi alpha 1, Go alpha, and the short from of Gs alpha. The G-protein alpha subunits Gi alpha 2, Gs alpha (long isoform), and Gq/11 alpha, and G-protein beta subunits were unchanged throughout the differentiation process. By immunoblot and indirect immunofluorescence studies on confluent preadipocytes, we showed that Gi alpha 2 is present in the endoplasmic reticulum and marginally in plasma membranes and nuclei. In contrast, antibodies to Gi alpha 3 stained the Golgi apparatus. The role of G proteins on preadipocyte proliferation was studied using Bordetella pertussis toxin. Exposure of growing cells to this toxin in the presence of fetal calf serum (FCS) decreased [3H]thymidine incorporation by 40% and induced a 40% increase in doubling time. This resulted in a 30% decrease in cell number per well after 48 h. These effects of B. pertussis toxin did not appear to be related to an increase in cyclic adenosine monophosphate (cAMP) concentration, because forskolin had the opposite effect on cell proliferation. Finally, B. pertussis toxin prevented serum-induced Raf1 association to the plasma membrane, possibly by disrupting FCS-induced G beta gamma effects on the Ras/Raf1 pathway. Since Go alpha and Gi alpha 1 subunits were absent in preadipocytes, we conclude that Gi2 and/or Gi3 proteins transduce some mitogenic signals of FCS through release of G beta gamma subunits. The subcellular distribution of Gi alpha 2 and Gi alpha 3 suggests that part of their functions result from interactions with components other than the plasma membrane.
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PMID:G proteins in adipocytes and preadipocytes: characterization, subcellular distribution, and potential roles for Gi2 and/or Gi3 in the control of cell proliferation. 873 7

In CHO cells transfected with the rat dopamine D2 receptor (long isoform), administration of dopamine per se elicited a concentration-dependent increase in arachidonic acid (AA) release. The maximal effect was 197% of controls (EC50=25 nM). The partial D2 receptor agonist, (-)-(3-hydroxyphenyl)-N-n-propylpiperidine [(-)-3-PPP], also induced AA release, but with somewhat lower efficacy (maximal effect: 165%; EC50=91 nM). The AA-releasing effect of dopamine was counteracted by pertussis toxin, by the inhibitor of intracellular Ca2+ release, 8-(N N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), by excluding calcium from the medium, by the phospholipase A2 (PLA2) inhibitor, quinacrine, and by long-term pretreatment with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). In addition, it was antagonized by the D2 antagonists, raclopride and (-)-sulpiride--but not by (+)-sulpiride--and absent in sham-transfected CHO cells devoid of D2 receptors. The results obtained contrast to the previous notion that dopamine and other D2 receptor agonists require the concomitant administration of calcium-mobilizing agents such as ATP, ionophore A-23187 (calcimycin), thrombin, and TRH, to influence AA release from various cell lines.
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PMID:Direct dopamine D2-receptor-mediated modulation of arachidonic acid release in transfected CHO cells without the concomitant administration of a Ca2+-mobilizing agent. 975 80

Presynaptic dopamine D2 receptors (D2Rs) regulate dopamine transporter (DAT) activity in the brain. A potential mechanism was suggested by the observations that somatodendritic D2R activation produces hyperpolarization and the velocity of DAT expressed in Xenopus laevis oocytes varies with changes in membrane potential. To investigate whether D2R regulation of DAT function is voltage-dependent, we coexpressed the long isoform of the human (h) D2R and the hDAT in oocytes. Most DAT substrates fully activate D2Rs at concentrations used to measure uptake. Thus, DAT function was compared under conditions of maximal D2R activation (0.1-10 microM DA) or maximal D2R blockade (DA + 1 microM (-)-sulpiride). D2R activation significantly increased [3H]DA uptake into unclamped oocytes expressing relatively lower velocities. Uptake measured with a saturating concentration of DA suggested a D2R-induced increase in Vmax. The D2R-mediated enhancement of DA uptake was not associated with changes in resting membrane potential and was abolished by pertussis toxin pretreatment. Furthermore, in voltage-clamped oocytes, D2R activation enhanced both DA uptake and DAT-mediated steady-state currents by as much as 70%. Activation of D2Rs resulted in a 59% increase in cell surface binding of the cocaine analog [3H]WIN 35,428; this effect was also abolished by pertussis toxin pretreatment. Saturation experiments confirmed that D2R activation was associated with an increased Bmax and unchanged Ki for [3H]WIN 35,428. These results suggest that D2R-induced up-regulation of DAT activity occurs via a voltage-independent mechanism that depends on G(i/o) activation and a rapid increase in expression of functional DAT molecules at the cell surface.
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PMID:Dopamine D2 receptor regulation of the dopamine transporter expressed in Xenopus laevis oocytes is voltage-independent. 1112 31

The dopamine D(2) receptor exists as a long (D(2a)) and a short (D(2b)) isoform generated by alternative splicing of the corresponding transcript, which modifies the length of the third cytoplasmic loop implicated in heterotrimeric G-protein-coupling. Anatomical data suggested that this segment regulates the intracellular traffic and localization of the receptor. To directly address this question we used a combination of tagging procedures and immunocytochemical techniques to detect each of the two D(2) receptor isoforms. Surprisingly, most of the newly synthesized receptors accumulate in large intracellular compartments, the plasma membrane being only weakly labeled, without significant difference between the two receptor isoforms. Double labeling experiments showed that this localization corresponded neither to endosomal compartments nor to the Golgi apparatus. The D(2) receptor is mostly retained in the endoplasmic reticulum (ER), the long isoform more efficiently than the short one. It is accompanied by a striking vacuolization of the ER, roughly proportional to the expression levels of the two receptor isoforms. This phenomenon is partly overcome by treatment with pertussis toxin. In addition, an intrinsic activity of the D(2) receptor isoforms is revealed by [(35)S]-GTP gamma S binding and cAMP assay, which suggested that expression of weakly but constitutively active D(2) receptors promotes activation of heterotrimeric G protein inside the secretory pathway. This mechanism may participate in the regulation of the cellular traffic of the D(2) receptors isoforms.
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PMID:Intracellular retention of the two isoforms of the D(2) dopamine receptor promotes endoplasmic reticulum disruption. 1168 11

We have earlier demonstrated that dopamine stimulates the liberation of the prostaglandin E(2) (PGE(2)) precursor, arachidonic acid, in Chinese hamster ovary cells transfected with the rat dopamine D(2) receptor (long isoform), also without concomitant administration of a Ca(2+)-releasing agent [Nilsson et al., Br J Pharmacol 1998;124:1651-8]. In the present report, we show that dopamine, under the same conditions, also induces a concentration-dependent increase in the production of PGE(2), with a maximal effect of 235% at approximately 100 microM, and with an EC(50) of 794 nM. The effect was counteracted by the D(2) antagonist eticlopride, pertussis toxin, the inhibitor of intracellular Ca(2+) release TMB-8, incubation in Ca(2+)-free experimental medium, and PKC desensitization obtained by chronic pretreatment with the phorbol ester TPA. It was also antagonized by the non-specific cyclooxygenase (COX) inhibitor, indomethacin, and by the selective COX-2 inhibitor, NS-398, but not by the specific COX-1 inhibitor, valeryl salicylate. Both the non-specific phospholipase A(2) inhibitor, quinacrine, and an inhibitor of cPLA(2) and iPLA(2), AACOF3, counteracted the effect; in contrast, a selective iPLA(2) inhibitor, BEL, and a selective sPLA(2) inhibitor, TAPC, were ineffective. No effects of dopamine were obtained in control cells mock-transfected with the p3C vector only. The results reinforce previous assumptions that dopamine may interact with eicosanoid metabolism by means of D(2) receptor activation, and implicate an involvement of cPLA(2) and COX-2 in this effect. It is suggested that measurement of dopamine-induced PGE(2) production may serve as a convenient way to study D(2) receptor function in vitro.
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PMID:Dopamine D(2) receptor-induced COX-2-mediated production of prostaglandin E(2) in D(2)-transfected Chinese hamster ovary cells without simultaneous administration of a Ca(2+)-mobilizing agent. 1211 Mar 74

A range of ligands displayed agonism at the long isoform of the human dopamine D(2) receptor, whether using receptor-G protein fusions or membranes of cells in which pertussis toxin-resistant mutants of individual Galpha(i)-family G proteins could be expressed in an inducible fashion. Varying degrees of efficacy were observed for individual ligands as monitored by their capacity to load [(35)S]GTPgammaS onto each of Galpha(i1),Galpha(i2),Galpha(i3), and Galpha(o1). By contrast, (S)-(-)-3-(3-hydroxyphenyl)-N-propylpiperidine was a partial agonist when Galpha(o1) was the target G protein but an antagonist/inverse agonist at Galpha(i1),Galpha(i2), and Galpha(i3). In ligand binding assays, dopamine identified both high- and low-affinity states at each of the dopamine D(2) receptor-G protein fusion proteins, and the high-affinity state was eliminated by guanine nucleotide. (S)-(-)-3-(3-hydroxyphenyl)-N-propylpiperidine bound to an apparent single state of the constructs in which the D(2) receptor was fused to Galpha(i1),Galpha(i2), or Galpha(i3). However, it bound to distinct high- and low-affinity states of the D(2) receptor-Galpha(o1) fusion, with the high-affinity state being eliminated by guanine nucleotide. Likewise, although dopamine identified guanine nucleotide-sensitive high-affinity states of the D(2) receptor when expression of pertussis toxin-resistant forms of each of Galpha(i1), Galpha(i2), Galpha(i3), and Galpha(o1) was induced, (S)-(-)-3-(3-hydroxyphenyl)-N-propylpiperidine identified a high-affinity site only in the presence of Galpha(o1). p-Tyramine displayed a protean ligand profile similar to that of (S)-(-)-3-(3-hydroxyphenyl)-N-propylpiperidine but with lower potency. These results demonstrate (S)-(-)-3-(3-hydroxyphenyl)-N-propylpiperidine to be a protean agonist at the D(2) receptor and may explain in vivo actions of this ligand.
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PMID:Protean agonism at the dopamine D2 receptor: (S)-3-(3-hydroxyphenyl)-N-propylpiperidine is an agonist for activation of Go1 but an antagonist/inverse agonist for Gi1,Gi2, and Gi3. 1729 57

Alternative splicing of the ryanodine receptor subtype 3 (RyR3) produces a short isoform (RyR3S) able to negatively regulate the ryanodine receptor subtype 2 (RyR2), as shown in cultured smooth muscle cells from mice. The RyR2 subtype has a crucial role in the control of vascular reactivity via the fine tuning of Ca(2+) signaling to regulate cerebral vascular tone. In this study, we have shown that the inhibition of RyR3S expression by a specific antisense oligonucleotide (asRyR3S) was able to increase the Ca(2+) signals implicating RyR2 in cerebral arteries ex vivo. Moreover, we tried to inhibit the expression of RyR3S in vivo. The asRyR3S was complexed with JetPEI and injected intravenously coupled with several methods known to induce a blood brain barrier disruption. We tested solutions to induce osmotic choc (mannitol), inflammation (bacteria lipopolysaccharide and pertussis toxin), vasoconstriction or dilatation (sumatriptan, phenylephrine, histamine), CD73 activation (NECA) and lipid instability (Tween80). All tested technics failed to target asRyR3 in the cerebral arteries wall, whereas the molecule was included in hepatocytes or cardiomyocytes. Our results showed that the RyR3 alternative splicing could have a function in cerebral arteries ex vivo; however, the disruption of the blood brain barrier could not induce the internalization of antisense oligonucleotides in the cerebral arteries, in order to prove the function of RYR3 short isoform in vivo.
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PMID:Blood brain barrier precludes the cerebral arteries to intravenously-injected antisense oligonucleotide. 2551 Feb 29