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)

The effects of the high affinity sigma (sigma) ligands 1,3-di(2-tolyl)guanidine (DTG), (+)N-cyclopropylmethyl-N-methyl-1,4-diphenyl-1- ethyl-but-3-en-1-yl-amine hydrochloride (JO-1784), (+)3-[3-hydroxyphenyl]-N-(1-propyl)piperidine hydrochloride [(+)3-PPP] and haloperidol were studied on N-methyl-D-aspartate (NMDA)-evoked release of [3H]noradrenaline (NA) from preloaded hippocampal slices made from Sprague-Dawley rats. The [3H]NA release was evoked once by a 4 min exposure to NMDA, 40 min after the beginning of superfusion with a Mg+(+)-free Krebs' solution. In the absence of any drug, NMDA evoked a concentration-dependent [3H]NA release. Mg++ and EGTA abolished the [3H]NA release induced by NMDA. JO-1784 and (+)3-PPP potentiated in a concentration-dependent manner NMDA-induced [3H]NA release, without affecting the basal outflow. DTG concentration-dependently inhibited the overflow of [3H]NA evoked by NMDA, without affecting the basal efflux. Haloperidol, which did not modify NMDA-evoked [3H]NA release by itself, completely prevented the effects of JO-1784, (+)3-PPP and DTG. In contrast, spiperone, also a potent dopamine receptor antagonist but with low affinity for sigma binding sites, failed to prevent the potentiation of NMDA-evoked release of [3H]NA by JO-1784 and (+)3-PPP. The possible involvement of Gi/o proteins in the modulation by sigma ligands of NMDA-evoked [3H]NA release in the rat hippocampus was also investigated. To this end, Gi/o proteins were inactivated with pertussis toxin (PTX), injected locally 3 to 11 days prior to the experiment or with in vitro preincubation with N-ethylmaleimide (NEM) for 30 min prior the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Modulation by sigma ligands of N-methyl-D-aspartate-induced [3H]noradrenaline release in the rat hippocampus: G-protein dependency. 140 2

Dihydroergocryptine and dihydroergocristine, two C-9, 10-hydrogenated ergot alkaloids, inhibited in a concentration-dependent manner prolactin release and cyclic AMP accumulation in cultured anterior pituitary cells. The inhibitory effect of dihydroergocryptine was more potent and started at lower concentrations than that of dihydroergocristine. Haloperidol and pimozide, two dopamine receptor antagonists, completely abolished the inhibitory activity of the ergot alkaloids. The involvement of the adenylate cyclase-cyclic AMP system in the inhibitory action of the two compounds was demonstrated by the antagonism by pertussis toxin of the reduction of both prolactin release and cyclic AMP accumulation produced by dihydroergocryptine and dihydroergocristine.
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PMID:Effect of dihydroergocryptine and dihydroergocristine on cyclic AMP accumulation and prolactin release in vitro: evidence for a dopaminomimetic action. 303 57

Electrical and pharmacological properties of currents induced by compounds having affinities for putative sigma receptors were investigated with NCB20 cells by use of the whole-cell patch-clamp technique. Antipsychotics and naloxone induced inward currents with a decrease in membrane conductance at a holding potential of -60 mV. The rank order of potency for compounds inducing these currents was bromperidol > haloperidol > mosapramine = clocapramine > carpipramine > chlorpromazine > remoxipride > naloxone. Sulpiride, which does not have affinity for sigma receptors, induced inward currents only slightly. Haloperidol-induced currents were not affected by the pretreatments with 10 microM of sulpiride, dopamine, atropine, N-methyl-D-aspartate, 2-amino-7-phosphonoheptanoic acid, morphine or A23187, 100 nM of ICS 205-930, 100 microM of forskolin, 1 microM of phorbol-12,13-dibutyrate, or 100 ng/ml of cholera or pertussis toxins. The reversal potential of the currents induced by haloperidol, naloxone or remoxipride was dependent on the concentration of external or internal potassium. These results indicate that the currents induced by the tested compounds are due to blockade of tonic, outward potassium currents and suggest that these agents act on putative sigma receptors and that the second messenger systems within the cell are not essential for the coupling between the receptors and the channels.
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PMID:Characterization of the currents induced by sigma ligands in NCB20 neuroblastoma cells. 791 Jan

1. Inhibition by haloperidol and chlorpromazine of a voltage-activated K+ current was characterized in rat phaeochromocytoma PC12 cells by use of whole-cell voltage-clamp techniques. 2. Haloperidol or chlorpromazine (1 and 10 microM) inhibited a K+ current activated by a test potential of +20 mV applied from a holding potential of -60 mV. The K+ current inhibition did not exhibit voltage-dependence when test potentials were changed between -10 and +40 mV or when holding potentials were changed between -120 and -60 mV. 3. Effects of compounds that are related to haloperidol and chlorpromazine in their pharmacological actions were examined. Fluspirilene (1 and 10 microM), an antipsychotic drug, inhibited the K+ current, but pimozide (1 and 10 microM), another antipsychotic drug did not significantly inhibit the K+ current. Sulpiride (1 or 10 microM), an antagonist of dopamine D2 receptors, did not affect the K+ current whereas (+)-SCH-23390 (10 microM), an antagonist of dopamine D1 receptors, reduced the K+ current. As for calmodulin antagonists, W-7 (100 microM), but not calmidazolium (1 microM), reduced the K+ current. 4. The inhibition by haloperidol or chlorpromazine of the K+ current was abolished when GTP in intracellular solution was replaced with GDP beta S. Similarly, the inhibition by pimozide, fluspirilene, (+)-SCH-23390 or W-7 was abolished or attenuated in the presence of intracellular GDP beta S. The inhibition by haloperidol or chlorpromazine was not prevented when cells were pretreated with pertussis toxin or when K-252a, an inhibitor of a variety of protein kinases, was included in the intracellular solution. 5. Haloperidol and chlorpromazine reduced a Ba2+ current permeating through Ca2+ channels. Inhibition by haloperidol or chlorpromazine of the Ba2+ current was not affected by GDP beta S included in the intracellular solution. 6. It is concluded that haloperidol and chlorpromazine inhibit voltage-gated K+ channels in PC12 cells by a mechanism involving GTP-binding proteins. The inhibition may not be related to their activity as antagonists of dopamine D2 receptors or calmodulin antagonists.
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PMID:Characterization of inhibition by haloperidol and chlorpromazine of a voltage-activated K+ current in rat phaeochromocytoma cells. 859 Sep 77

In this study, the ligand-receptor-G protein interactions of the dopamine D3 receptor expressed in Chinese hamster ovary cells were investigated using guanosine 5'-[gamma-thio]triphosphate-[35S] ([35S]GTPgammaS) and receptor binding experiments. Dopamine stimulated the [35S]GTPgammaS binding in a guanine nucleotide, magnesium and sodium-dependent manner. Dopamine and quinpirole produced maximal stimulation of the [35S]GTPgammaS binding whereas (+)-7-OH-DPAT and (-)-3-PPP were partial agonists. Interestingly, several compounds previously classified as D2 receptor antagonists behaved as inverse agonists at the D3 receptor, i.e., they inhibited the basal [35S]GTPgammaS binding in a dose dependent fashion. Haloperidol, (+)-UH-232, (+)-AJ-76 and raclopride were full inverse agonists but clozapine was a partial inverse agonist. Pertussis toxin treatment abolished the D3 receptor-mediated agonist as well as inverse agonist responses, indicating the involvement of Gi/Go proteins in both processes. According to the ternary complex model, agonists should bind with higher affinity to the G protein coupled receptor (RG) and thereby shift the equilibrium from free receptor (R) toward RG, which produces a biological response. However, an inverse agonist should bind with higher affinity to R than to RG and thereby inhibit the basal activity of the cell. We found that the high affinity agonist binding site (RG) was abolished by pertussis toxin treatment of the cells. However, the inverse agonists bound with the same affinity to untreated and pertussis toxin treated D3 receptor membranes. Thus, we found no evidence for the hypothesis that inverse agonists would shift the equilibrium from RG toward R by binding with higher affinity to R than to RG.
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PMID:Agonist and inverse agonist activity at the dopamine D3 receptor measured by guanosine 5'--gamma-thio-triphosphate--35S- binding. 953 1

Human dopamine D(2) (hD(2)) and D(3) (hD(3)) receptors were expressed at similar, high expression levels in Chinese hamster ovary (CHO) cells, and their coupling to G proteins and further signal transduction pathways were compared. In competition radioligand-binding experiments, guanosine-5'-O-(3-thio)triphosphate (GTPgammaS) treatment of hD(2S)- or hD(3)-CHO cell membranes induced a rightward shift and steeping of the dopamine inhibition curve. This effect was pronounced for hD(2) receptors and small for hD(3) receptors. Activation of G proteins was investigated in [(35)S]GTPgammaS-binding assays. Dopamine stimulated [(35)S]GTPgammaS binding 330 and 70% over basal levels on hD(2)-CHO and hD(3)-CHO cell membranes, respectively. (+)-7-(Dipropylamino)-5, 6,7,8-tetrahydro-2-naphthalenol and PD128907 were partial agonists for both receptors. Haloperidol, risperidone, raclopride, and nemonapride inhibited dopamine-stimulated [(35)S]GTPgammaS binding with potencies comparable to their binding affinities for hD(2) and hD(3) receptors in CHO cell membranes; inverse agonism could not be detected with this assay. Receptor stimulation by dopamine inhibited forskolin-induced cyclic AMP formation in hD(2)-CHO and hD(3)-CHO cells by 70%. Furthermore, the extracellular acidification rate increased when hD(2)-CHO and hD(3)-CHO cells were stimulated by dopamine; this effect was abolished by pertussis toxin pretreatment. In this study, we could demonstrate clear functional effects at different levels of the signaling cascade of hD(2) and hD(3) receptors in CHO cells when expressed at high levels. High-affinity agonist binding to hD(2) and hD(3) receptors was still present, but effects of receptor-G protein uncoupling at hD(3) receptors were small, indicating that hD(3) receptors maintain relatively high-affinity agonist binding in the absence of G proteins.
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PMID:Comparison of the ligand binding and signaling properties of human dopamine D(2) and D(3) receptors in Chinese hamster ovary cells. 1041 8