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Biomedical subjects

A Lucacchini

Publications and source records attributed to A Lucacchini.

At least 127 records · Page 7Linked to original sources
PubMed1993

Synthesis of 7-(2-dimethylaminovinyl) derivatives of pyrazolo[1,5-a] pyrimidines, as precursors of new tricyclic series. Binding studies of BDZ receptor.

A series of 7-dimethylaminovinylpyrazolo[1,5-a]pyrimidines bearing an acetyl or an ethoxycarbonyl group at the 6-position turned out to be useful intermediates for the synthesis of pyrazolo[1,5-a]pyrido[3,4-e]pyrimidines and 8H-pyrazolo[5',1':2,3]pyrimido[5,4-d][1,2]diazepines. These tricyclic derivatives were studied for their affinity for the central benzodiazepine receptor, and meaningful suggestions about the structure-affinity relationship were obtained. Some of the above intermediates were also reacted with S-methylthiourea, to give a mixture of pyrazolo[5',1':1,2]pyrimido[5,6-e][1,3]diazocines and pyrazolo[1,5-a]quinazolines.

Binding, Competitive↗
PubMed1993

Studies on annelated 1,4-benzothiazines and 1,5-benzothiazepines. VII. Synthesis and inhibition of benzodiazepine receptor binding of some 4,5-dihydro-tetrazolo[5,1-d]-1,5-benzothiazepines and 5-phenyl-s-triazolo[3,4-d]-1,5-benzothiazepines.

The 4,5-dihydro-tetrazolo[5,1-d]-1,5-benzothiazepines 3a-k and the 5-phenyl-s-triazolo[3,4-d]-1,5-benzothiazepines 6a-f and 11a-c have been prepared and tested for their ability to displace [3H] flunitrazepam binding from bovine brain membranes. Some of the triazoloderivatives showed moderate binding affinity for the benzodiazepine receptor.

Animals↗
PubMed1993

Reaction of 1-aminophthalazines with alpha-halocarbonyl compounds: imidazo[2,1-a]phthalazines and their benzodiazepine receptor activities.

The one-pot synthesis and the benzodiazepine receptor binding activity of some imidazo[2,1-a]phthalazines bearing different substituents at position-2 and/or 3 and/or 6 is reported. The dissimilar binding results of the reported compounds are discussed in relation to the nature and/or position of the substituents on the tricyclic ring system.

Animals↗
PubMed1992

Benzodiazepine receptor affinity and interaction of some N-(indol-3-ylglyoxylyl)amine derivatives.

Several derivatives, in which tryptamine, tyramine, and dopamine moieties are linked to the indole nucleus by an oxalyl bridge, were tested for their ability to displace the specific binding of [3H]flunitrazepam from bovine brain membranes. GABA ratio and in vivo tests for the most potent compounds showed they behave as inverse agonists at the benzodiazepine receptor (BzR). To better define the structure-activity relationship (SAR) of this kind of ligand, several phenylethylamine derivatives were synthesized to evaluate their affinity to BzR. Some of these derivatives (17, 21, 24, 26, and 30) were found to exhibit high affinity (Ki = 0.51-0.085 microM) for BzR and possessed a partial agonist activity, although their chemical structure is closely related to tryptamine 2-6, tyramine 7-11, and dopamine 12-16 derivatives. A different interaction of these ligands to the receptor site is hypothesized. Moreover, all the prepared 1-methyl derivatives exhibited very low binding affinity to BzR.

Animals↗
PubMed1992

Conformational effects on the activity of drugs. 13. A revision of previously proposed models for the activation of alpha- and beta-adrenergic receptors.

The alpha 1-, alpha 2-, beta 1-, and beta 2-adrenergic properties of the 2-(3,4-dihydroxyphenyl)morpholines 3 and 4 (2-DPMs), of the 3-(3,4-dihydroxyphenyl)-3-piperidinols 5 and 6 (3-DPPs), and of the trans-2-amino-5,6-dihydroxytetrahydronaphthalen-1-ols 7 and 8 and the trans-2-amino-6,7-dihydroxytetrahydronaphthalen-1-ols 9 and 10 (2-ADTNs) were evaluated in vitro both by radioligand binding assays and by functional tests on isolated preparations and compared with those of norepinephrine (NE, 1) and isoprenaline (ISO, 2). Through a comparison of the stereostructures of the compounds examined with their biopharmacological properties, it was possible to revise previously proposed molecular models for the direct activation of alpha- and beta-adrenergic receptors. The revised models (A-C) provided information about the conformational requirements of adrenergic drugs, which substantially fit in with the results of several published studies involving conformationally-restricted adrenoceptor agonists. The different position of the catecholic hydroxyl groups in model B, which refers to the alpha 2 receptors, and in model C, which refers to the beta receptors, confirms the importance of the rotameric position of the aromatic ring of catecholamines in the interaction with the alpha- and beta-adrenergic receptor.

Animals↗
PubMed1992

Specific inhibition of binding to benzodiazepine receptors by 1,2,3-triazole derivatives.

Certain 1,2,3-triazole derivatives were prepared and tested for their ability to displace [3H]diazepam that was bound to bovine brain membrane protein. All the tested compounds are essentially lacking in this ability, except for B.1, which inhibited binding of [3H]diazepam in 50% of the trials at 2.5 microM. The structure of B.1, with a 1,2,3-triazole ring with acidic properties, supports the hypothesis proposed for binding to the benzodiazepine receptor site. Comparison of B.1 with 1,2,3-triazole derivatives bearing a bicyclic substituent in position 1 of the heterocyclic ring suggests that a high steric hindrance increases the affinity of a compound for the benzodiazepine receptor.

Animals↗
PubMed1992

Binding of the benzodiazepine ligand [3H]-RO 15-1788 to membrane preparations of the rabbit and turtle retina.

1. We have studied the binding of [3H]-RO 15-1788 to membrane preparations of the retina of rabbit (Lepus cunicula) and turtle (Pseudemys scripta elegans). 2. In both species, [3H]-RO 15-1788 binding was maximal at 0 degrees C and decreased with increasing temperature. It was saturable, protein concentration-dependent and specific. Flunitrazepam, unlabelled RO 15-1788 and ethyl-beta-carboline were the most effective displacers, whereas RO 5,4864 was ineffective. 3. In both turtle and rabbit retina, Scatchard analysis indicated the presence of a single binding site for [3H]-RO 15-1788. The KD was 0.75 nM in both turtle and rabbit, while the Bmax were 520 and 250 fmol/mg protein in turtle and rabbit respectively. A study of the association rate of [3H]-RO 15-1788 binding revealed faster kinetics in turtle, as compared to rabbit.

Animals↗
PubMed1992

Tricyclic heteroaromatic systems. Synthesis and benzodiazepine binding activity of 1-substituted-3-methyl- and 3-phenylpyrazolo[4,5-c]quinolin-4-ones.

The synthesis and the benzodiazepine binding activity of some 3-methyl- and 3-phenylpyrazolo[4,5-c]quinolin-4-ones bearing a heterocyclic or a substituent which is different from an aryl moiety at position-1 are reported. Molecular modelling is used to correlate the binding affinity to the chemical features and to justify the reduced receptor affinities of the reported compounds with respect to that of CGS 8216 which is taken as the lead compound.

Animals↗
PubMed1991

Tricyclic heteroaromatic systems: [1]benzopyrano-pyrazol-4-ones as benzodiazepine receptor ligands.

The synthesis of a series of 8-substituted 1,4-dihydro-1-aryl-3-methyl-[1]benzopyrano[3,4-d]pyrazol-4-ones (series 7) 2,4-dihydro-2-aryl-3-methyl[1]benzopyrano[4,3-c]pyrazol-4-ones (series 8) is reported. Compounds of series 7 and 8 were tested for their ability to displace [3H]flunitrazepam from bovine brain membranes and for their in vitro biological activity. The results allowed some conclusions to be drawn about the structural requirements of the benzodiazepine recognition site within this class of unusual ligands.

Animals↗
PubMed1991

Platelet peripheral benzodiazepine receptors are decreased in Parkinson's disease.

Peripheral benzodiazepine (BDZ) receptors are located in a variety of tissues, including platelets, in the nuclear and/or mitochondrial membranes. We studied the density of peripheral BDZ receptors in platelets of 10 de novo Parkinson's disease (PD) patients, 18 PD patients treated with a levodopa/carbidopa combination, and in 15 healthy subjects matched for sex and age. The binding assay was conducted using [3H]PK 11195, a specific ligand for peripheral BDZ receptors. A significant decrease in the density of [3H]PK 11195 binding sites has been observed in PD patients with respect to controls (p less than 0.01), but not between de novo and treated PD patients. No correlation has been found between the decrease in density of [3H]PK 11195 binding sites in platelets and either the duration or severity of PD. Peripheral BDZ receptors are implicated in the regulation of mitochondrial respiratory function. Thus, their decrease in PD might parallel the abnormalities in mitochondrial function recently found in this neurologic disease.

Aged↗
PubMed1991

Characterization of NK-3 binding sites in rat and guinea pig cortical membranes by the selective ligand [3H]Senktide.

We have used [3H]Senktide, a selective Neurokinin B receptor ligand, for the characterization of NK-3 receptors in rat and guinea pig CNS membranes. Scatchard analysis of saturation binding studies in cerebral cortex membranes indicated that this ligand bound to a single site with apparent high affinity (KD = 4.6 +/- 1.6 and 3.1 +/- 0.37 nM, Bmax = 13.7 +/- 1.6 and 21.8 +/- 2.2 fmol/mg protein in rat and guinea pig membranes, respectively). However, in competition studies with a group of neurokinins and related peptides two different rank orders of affinities were obtained, as follows: NKB greater than [MePhe7]-NKB greater than or equal to Arg0-NKB greater than or equal to Senktide much greater than NKA greater than SP, in rat membranes, and [MePhe7]NKB greater than Senktide = NKB greater than Arg0-NKB much greater than SP greater than NKA, in guinea pig membranes.

Amino Acid Sequence↗
PubMed1991

Tricyclic heteroaromatic systems. Synthesis of 1,3 and 1,2 disubstituted [1]benzopyrano[4,3-b]pyrrol-4-ones and structure-activity relationships as benzodiazepine receptor ligands.

The synthesis of some 1,3- and 1,2- disubstituted [1]benzopyrano-pyrrol-4-ones is reported as well as their benzodiazepine receptor affinity, as measured by the ability to displace [3H]flunitrazepam from its specific central binding. The structure-activity relationships on the whole series of disubstituted [1]benzopyrano-pyrrol-4-ones show the importance of the presence of the 1-aryl substituent and the size limitation of the 3-substituent. The size of the latter seems also to be important for the "in vitro" efficacy.

Animals↗
PubMed1990

Superoxide dismutase-like activity of 1,2,3-triazole derivatives.

This paper reports the synthesis of some sulfurated 1,2,3-triazole derivatives and the biological evaluation, for the superoxide dismutase-like activity, of these new compounds together with several 1,2,3-triazoles previously described by us. All the compounds possess a SOD-like activity and some of them showed an activity equivalent to or higher than those of penicillamine or thiopronin, which are well known therapeutic drugs in the treatment of rheumatoid arthritis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1990

Stress-related changes of benzodiazepine binding inhibitory activity (B.B.I.A.) in humans.

The presence of benzodiazepine binding inhibitory activity (B.B.I.A.) in sera from 44 psychiatric patients and from 14 healthy volunteers, prompted us to investigate whether or not this activity underwent changes in stressful situations. We measured the inhibitory units (IU) of deproteinized sera of 12 subjects, immediately before and 2 weeks after sitting for a difficult university exam. Our results showed significantly higher IU values (i.e., higher B.B.I.A. concentrations) in the samples taken just before the exam. This preliminary finding clearly suggests the involvement of B.B.I.A. in anxiety mechanisms.

Adult↗