Publications (11)32.83 Total impact
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Article: Cloning and characterization of a novel human 5-HT4 receptor variant that lacks the alternatively spliced carboxy terminal exon. RT-PCR distribution in human brain and periphery of multiple 5-HT4 receptor variants.
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ABSTRACT: We have cloned a novel C-terminal splice variant of serotonin 5-HT4 receptors from human hippocampus. The deduced protein extends only one aminoacid past the splicing point. We propose to call the novel variant h5-HT4(n) since it contains none of the C-terminal exons alternatively spliced in other variants. The pharmacological profile of h5-HT4(n) stably expressed in HeLa cells is in agreement with other reported variants. Stably transfected cells showed increased basal levels of intracellular cAMP in absence of agonist, indicating constitutive activity of the expressed receptors. 5-HT induced robust increases of intracellular cAMP. The 5-HT4 receptor antagonist GR 113808 blocked the effects of 5-HT and brought intracellular cAMP below basal constitutive levels, indicating inverse agonism of this compound in this system. The RT-PCR distribution of all known human C-terminal splice variants in human brain regions and periphery showed complex patterns of variant expression, with the novel variant h5-HT4(n) being widely and abundantly expressed.Neuropharmacology 02/2002; 42(1):60-73. · 4.81 Impact Factor -
Article: Synthesis and biological evaluation of 2,5-dihydropyrazol.
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ABSTRACT: A novel series of 2,5-dihydropyrazolo[4,3-c]quinolin-3-ones has been prepared. These compounds showed good PDE 4 inhibitory activity and weak affinity for rolipram's binding site. They also exhibited a good anti-inflammatory profile without emetic side effects.Bioorganic & Medicinal Chemistry Letters 01/2001; 10(23):2661-4. · 2.55 Impact Factor -
Article: Benzyl derivatives of 2,1,3-benzo- and benzothieno[3,2-a]thiadiazine 2,2-dioxides: first phosphodiesterase 7 inhibitors.
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ABSTRACT: The synthesis of a new family of benzyl derivatives of 2,1,3-benzo- and benzothieno[3,2-a]thiadiazine 2,2-dioxides was achieved. The biological data revealed the first heterocyclic family of compounds with PDE 7 inhibitory properties appearing to be a new objective for the treatment of T-cell-dependent disorders. The IC(50) values or percent inhibition values of the compounds against PDE 7 were calculated by testing them against human recombinant PDE 7 expressed in S. cerevisiae. In this expression system the only cyclic nucleotide hydrolyzing activity present in cell extracts corresponded to human PDE 7. Isoenzyme selectivity PDE 7 versus PDE 4 and PDE 3 was also measured. Considering simultaneously inhibition of the three different isoenzymes, monobenzyl derivatives 15 and 23 showed interesting PDE 7 potency (around 10 microM); although not statistically significant, a trend toward selectivity with respect to PDE 3 and PDE 4 was obtained. Benzothiadiazine 16, although less potent at PDE 7 (IC(50) = 25 microM), also showed a trend of selectivity toward PDE 3 and PDE 4. These compounds are considered the best leads for further optimization.Journal of Medicinal Chemistry 03/2000; 43(4):683-9. · 5.25 Impact Factor -
Article: Design, synthesis, and biological activities of new thieno[3,2-d] pyrimidines as selective type 4 phosphodiesterase inhibitors.
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ABSTRACT: A common pharmacophore for compounds structurally related to nitraquazone has been derived. Using this pharmacophore, new structures have been designed, synthesized, and evaluated for their inhibitory potencies against cyclic adenosine 5'-monophosphate (cAMP) specific phosphodiesterase (PDE 4). From these compounds, 4-benzylamino-2-butylthieno[3,2-d]pyrimidine (4) was selected for optimization. The effects of changes to the lipophilic groups and the amino linkage on the PDE 4 activity have been investigated. As a result, some potent PDE 4 inhibitors, selective with respect to PDE 3, have been identified. A selected group of compounds have been further evaluated for their ability to displace [3H]rolipram from its binding site and also to potentiate isoprenaline-induced cAMP accumulation in isolated guinea pig eosinophils. Of these, 2-butyl-4-cyclohexylaminothieno[3,2-d]pyrimidine (33) has an interesting profile, with an important improvement in PDE 4/[3H]rolipram ratio with respect to reference drugs, and good activity in cAMP potentiation, consistent with efficient cell penetration.Journal of Medicinal Chemistry 11/1998; 41(21):4021-35. · 5.25 Impact Factor -
Article: Phosphodiesterase inhibitory properties of losartan. Design and synthesis of new lead compounds.
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ABSTRACT: A 4-centre PDE4 pharmacophore search has been carried out in several 3D-databases containing compounds belonging to different therapeutic areas. Losartan, an angiotensin-II antagonist, has been identified as a new lead compound for developing PDE4 inhibitors. New families of compounds derived from losartan has been synthesized and their PDE inhibition has been measured.Bioorganic & Medicinal Chemistry Letters 04/1998; 8(5):505-10. · 2.55 Impact Factor -
Article: Characterization of human serotonin 1D and 1B receptors using [3H]-GR-125743, a novel radiolabelled serotonin 5HT1D/1B receptor antagonist.
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ABSTRACT: The study of serotonin (5-HT) receptors from the points of view of their anatomical localization and pharmacological characterization has been linked to the availability of highly selective radioligands exhibiting high affinity for their targets. This is particularly so in the case of serotonin receptors, since many different subtypes with overlapping pharmacological profiles have been described. Of these, the serotonin 5-HT1 receptor family appears to be the most complex in terms of molecular diversity and pharmacological properties. The lack of appropriate tools to characterize the different receptor subtypes included in this family has hampered progress in the understanding of biological function. In the case of serotonin 5-HT1D receptors all the radioligands used so far in their characterization behave as agonists from the functional point of view. This agonistic character is regarded as a disadvantage for radioligands since their interaction with the receptors under study depends on factors other than the abundance of the receptor, such as the coupling of the receptors with G-proteins. We describe here the binding properties of [3H]-GR-125743, a new radiolabelled derivative of a compound that exhibits selective antagonistic properties with respect to the serotonin human (h5-HT1D) and human (h5-HT1B) receptors. The compound has been characterized for its ability to label the cloned h5-HT1D and h5-HT1B receptors. The binding obtained in both cases was specific, saturable and reversible, whereas the percentage of specific binding depended on the level of expression of the receptors. Using saturation analysis we have found that, on the specific clones used in this study, the compound labels a receptor population 5 to 10-fold higher that the one revealed using [3H]-5-carboxamidotryptamine, a compound with agonist properties for these receptors in functional assays. Using [3H]-GR-125743 as a radioligand we have characterized the pharmacological profile of the same cloned h5-HT1D and h5-HT1B receptor preparations for a range of serotonin reference compounds by means of displacement assays. The affinities found have been compared, using regression analysis, with those obtained for the same radioligand and compounds in membranes obtained from human substantia nigra, a tissue known to be rich in hS-HT(1B/1D) receptors. We have found a better correlation, both in terms of correlation coefficient and of slope, between the substantia nigra data and the h5-HT1B data compared with the h5-HT1D data (0.94 and 1.05 vs. 0.86 and 0.64 respectively). Finally, the addition of 100 microM GTP reduced the binding of [3H]-GR-125743 to h5-HT1D and h5-HT1B receptor subtypes by approximately 20% without affecting the affinities obtained for different displacers. Therefore, [3H]-GR-125743 appears to be a suitable radioligand for the characterization of h5-HT1D and h5-HT1B receptor subtypes, being potentially more useful than previously existing compounds.Archiv für Experimentelle Pathologie und Pharmakologie 10/1997; 356(3):328-34. · 2.65 Impact Factor -
Article: Novel heterocyclic-fused pyridazinones as potent and selective phosphodiesterase IV inhibitors.
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ABSTRACT: A series of 6-aryl-4,5-heterocyclic-fused pyridazinones were designed and synthesized as selective phosphodiesterase (PDE) IV inhibitors. Biological evaluation of these compounds demonstrated a good selectivity profile toward the PDE IV family and greatly attenuated affinity for the Rolipram high-affinity binding site that seems to be responsible for undesiderable side effects. Structure-activity relationships (SARs) studies showed that the presence of an ethyl group at pyridazine N-2 is associated with the best potency and selectivity profile.Journal of Medicinal Chemistry 06/1997; 40(10):1417-21. · 5.25 Impact Factor -
Article: Identification and characterization of serotonin 5-HT4 receptor binding sites in human brain: comparison with other mammalian species.
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ABSTRACT: Specific binding for the 5-HT4-selective radioligand [3H]GR 113808 has been identified in human and calf brain membranes. Using human tissue the distribution of the binding was heterogeneous throughout different brain regions, being highest in the caudate nucleus. For this region a Kd value of 0.59 +/- 0.08 nM and a Bmax of 225 +/- 2.6 fmol/mg were obtained. Other regions with substantial densities were the lenticular nucleus, the substantia nigra, the hippocampus and the frontal cortex, whereas no binding could be detected in the cerebellum. The ability of several standard compounds in displacing the radioligand was compatible with the labelling of 5-HT4 receptors. Correlation analysis showed no significant differences amongst data obtained for these compounds using human, calf and guinea-pig membranes.Molecular Brain Research 02/1994; 21(1-2):176-80. · 2.00 Impact Factor -
Article: Pancopride, a potent and long-acting 5-HT3 receptor antagonist, is orally effective against anticancer drug-evoked emesis.
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ABSTRACT: Pancopride ((+-)N-(1-azabicyclo-[2,2,2]-oct-3-yl)-2-cyclopropylmethoxy-4-ami no-5-chlorobenzamide) is a new potent and selective 5-HT3 receptor antagonist, orally and parenterally effective against cytotoxic drug-induced emesis. In vitro, pancopride displayed high affinity (Ki = 0.40 nM) for [3H]GR65630-labelled 5-HT3 recognition sites in membranes from the cortex of rat brains. In vivo, pancopride antagonized 5-HT-induced bradycardia in anaesthetized rats when administered i.v. 5 min (ID50 = 0.56 microgram/kg) or p.o. 60 min (ID50 = 8.7 micrograms/kg) before 5-HT challenge. A single oral dose (10 micrograms/kg) of pancopride produced a significant inhibition of the bradycardic reflex over an 8-h period. Pancopride dose dependently inhibited the number of vomiting episodes and delayed the onset of vomiting induced by cisplatin in dogs (ID50 = 3.6 micrograms/kg i.v. and 7.1 micrograms/kg p.o.). Pancopride was also effective in blocking mechlorethamine- and dacarbazine-induced emesis. Unlike metoclopramide, pancopride was shown to lack any measurable antidopaminergic activity both in vitro and in vivo. These results support clinical data, indicating that pancopride will be a useful drug for treating cytostatic-induced emesis in humans.European Journal of Pharmacology 12/1992; 222(2-3):257-64. · 2.52 Impact Factor -
Article: Identification and characterization of serotonin 5-HT4 receptor binding sites in human brain: comparison with other mammalian species
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ABSTRACT: Specific binding for the 5-HT4-selective radioligand [3H]GR 113808 has been identified in human and calf brain membranes. Using human tissue the distribution of the binding was heterogeneous throughout different brain regions, being highest in the caudate nucleus. For this region a Kd value of 0.59 ± 0.08 nM and a Bmaxof 225 ± 2.6 fmol/mg were obtained. Other regions with substantial densities were the lenticular nucleus, the substantia nigra, the hippocampus and the frontal cortex, whereas no binding could be detected in the cerebellum. The ability of several standard compounds in displacing the radioligand was compatible with the labelling of 5-HT4 receptors. Correlation analysis showed no significant differences amongst data obtained for these compounds using human, calf and guinea-pig membranes.Molecular Brain Research. -
Article: Cloning and characterization of a novel human 5-HT4 receptor variant that lacks the alternatively spliced carboxy terminal exon. RT-PCR distribution in human brain and periphery of multiple 5-HT4 receptor variants
[show abstract] [hide abstract]
ABSTRACT: We have cloned a novel C-terminal splice variant of serotonin 5-HT4 receptors from human hippocampus. The deduced protein extends only one aminoacid past the splicing point. We propose to call the novel variant h5-HT4(n) since it contains none of the C-terminal exons alternatively spliced in other variants. The pharmacological profile of h5-HT4(n) stably expressed in HeLa cells is in agreement with other reported variants. Stably transfected cells showed increased basal levels of intracellular cAMP in absence of agonist, indicating constitutive activity of the expressed receptors. 5-HT induced robust increases of intracellular cAMP. The 5-HT4 receptor antagonist GR 113808 blocked the effects of 5-HT and brought intracellular cAMP below basal constitutive levels, indicating inverse agonism of this compound in this system. The RT-PCR distribution of all known human C-terminal splice variants in human brain regions and periphery showed complex patterns of variant expression, with the novel variant h5-HT4(n) being widely and abundantly expressed.Neuropharmacology.
