Publications by authors named "Ilario Mereghetti"

The wobbler mouse is a model of selective motor neuron degeneration in the cervical spinal cord. Comparing cervical and lumbar tracts of control and diseased mice at the early stage of pathology by proteomic analysis, we identified 31 proteins by peptide mass fingerprint after tryptic digestion and MALDI-TOF analysis, that were differently represented among the four experimental groups. In healthy mice, patterns of protein expression differed between cervical and lumbar tract: proteins of cellular energetic metabolism pathway showed lower expression in the cervical tract, while cellular trafficking proteins were overrepresented.

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A series of new compounds containing a benzimidazole, benzothiazole, or benzoxazole nucleus linked to an arylpiperazine by different thioalkyl chains was prepared. They were tested in radioligand binding experiments to evaluate their affinity for 5-HT 1A and 5-HT 2A serotonergic, alpha 1 adrenergic, D1, and D2 dopaminergic receptors. Many of tested compounds showed an interesting binding profile; in particular, 36 displayed very high 5-HT 1A receptor affinity and selectivity over all the other investigated receptors.

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With the aim to develop new potent and selective ligands of 5-HT(3)-type serotonin receptors and to acquire more information on their structure-affinity relationships, new thieno[2,3-d]pyrimidine derivatives 32-39 were synthesized and their binding to 5-HT(3) versus 5-HT(4 )receptors was studied. Some of these new compounds exhibit good affinity for cortical 5-HT(3) receptors, but not for 5-HT(4) receptors. Among these derivatives, 6-ethyl-4-(4-methyl-1-piperazinyl)-2-(methylthio)thieno[2,3-d]pyrimidine 32 is the most potent ligand (K(i) = 67 nM); it behaves as a competitive antagonist of the 5-HT(3) receptor function in the guinea pig colon.

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The 21-amino acid peptide endothelin-1 (ET-1) is the predominant isoform of the endothelin peptide family, which includes ET-2, and ET-3. These peptides display a variety of physiological activities including vasoconstriction and the stimulation of cell proliferation in tissues both within and outside of the cardiovascular system. They exert their actions via activation of two distinct receptor subtypes, ET(A) and ET(B), belonging to the G protein-coupled receptor (GPCR) superfamily.

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We have tested by [(35)S]-GTPgammaS binding the intrinsic activity of three full agonists (serotonin, 5-methoxytryptamine and 5-methoxy-2-methyl-N,N-dimethyltryptamine) on rat 5-HT(6) receptors cloned in HEK-293 cells, using the scintillation proximity assay. Serotonin and 5-methoxytryptamine are soluble in water, while the agonist 5-methoxy-2-methyl-N,N-dimethyltryptamine is soluble in dimethyl sulfoxide (DMSO). In [(35)S]-GTPgammaS binding 5-HT and 5-methoxytryptamine were able to increase basal binding, while 5-methoxy-2-methyl-N,N-dimethyltryptamine surprisingly showed an inverse agonist activity.

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The affinities of the enantiomers of 1,3,4,14b-tetrahydro-2,10-dimethyl-2H,10H-pyrazino[2,1-d]pyrrolo[1,2-b] [1,2,5]benzotriazepine (10-methyl-10-azaaptazepine, 5) and 2-methyl-1,3,4,14b-tetrahydro-2H-pyrazino[2,1-d]pyrrolo[1,2-b] [1,2,5]benzothiadiazepine 10,10-dioxide (tiaaptazepine, 6) were evaluated in receptor binding assays. Compound (+)-(S)-5, the most significant tested enantiomer, showed good affinities for 5-HT1A, 5-HT2A 5-HT2C and alpha2NA receptors, moderate affinities for DA1, DA3r and 5-HT3 receptors and it was devoid of affinity for DA2, alpha(1NA) and muscarinic receptors. Compound (+)-(S)-5 showed an interesting pharmacological profile different from those of the reference compounds mirtazepine, mianserin and 6-methoxymianserin.

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The discovery of a new series of selective and high-affinity alpha(1)-adrenoceptor (alpha(1)-AR) ligands, characterized by a 1H-pyrrolo[2,3-d]-pyrimidine-2,4(3H,7H)-dione system, is described in this paper. Some synthesized compounds, including 20, 22, and 30, displayed affinity in the nanomolar range for alpha(1)-ARs and substantial selectivity with respect to 5-HT(1A) and dopaminergic D(1) and D(2) receptors. Functional assays, performed on selected derivatives, showed antagonistic properties.

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Endothelin-1 (ET-1), a peptide of 21 amino acid residues, is the most potent vasoconstrictor substance known and now it is understood to be one of a family of three mammalian vasoactive peptides that also includes ET-2 and ET-3. The endothelins (ETs) affect multiple organ systems and seem to be involved in the pathogenesis of many diseases such as hypertension, pulmonary hypertension, atherosclerosis, apoptosis inhibition and angiogenesis. The ETs exert their effects via activation of two distinct G-protein coupled receptor subtypes termed ET(A) and ET(B).

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Endothelins (ETs) are the most ubiquitous, highly potent and unusually long-lasting peptidic constrictors of human vessels known. Elevated levels of the plasma concentration of ETs were observed in several diseases such as hypertension, acute myocardial infarction, congestive heart failure, renal failure, pulmonary hypertension, and atherosclerosis. ETs exert their activities via specific seven-transmembrane, G protein-coupled receptors.

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Novel compounds characterized by a pyrrolo[3,2-d]pyrimidine-2,4-dione (PPm) system connected through an alkyl chain to a phenylpiperazine (PPz) residue were designed as structural analogues of the alpha(1)-adrenoceptor (alpha(1)-AR) ligand RN5 (1). In this new series of derivatives an arylpyrrolo moiety has replaced the indole nucleus of RN5. Several structural modifications were performed on the PPm and PPz moieties and the connecting alkyl chain.

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Using rational drug design to develop atypical antipsychotic drug candidates, we generated novel and metabolically stable pyrrolobenzazepines with an optimized pK(i) 5-HT(2A)/D(2) ratio. 5a, obtained by a new palladium-catalyzed three-step synthesis, was selected for further pharmacological and biochemical investigations and showed atypical antipsychotic properties in vivo. 5a was active on conditioned avoidance response at 0.

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Recently we reported the pharmacological characterization of the 9,10-dihydropyrrolo[1,3]benzothiazepine derivative (S)-(+)-8 as a novel atypical antipsychotic agent. This compound had an optimum pK(i) 5-HT(2A)/D(2) ratio of 1.21 (pK(i) 5-HT(2A) = 8.

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