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Biomedical subjects

G Giannaccini

Publications and source records attributed to G Giannaccini.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1990

Tricyclic heteroaromatic systems. [1]benzopyranopyrrol-4-ones and [1]benzopyrano-1,2,3-triazol-4-ones as benzodiazepine receptor ligands. Synthesis and structure-activity relationships.

The synthesis, ability to displace [3H]flunitrazepam binding from bovine brain membranes, and GABA ratio of some [1]benzopyranopyrroles 1a-i and [1]benzopyrano-1,2,3-triazoles 2a,b are reported. The GABA ratios of some previously synthesized pyrazoloquinolines A and [1]benzopyranopyrazoles C are also presented in order to draw some structure-activity relationships among our benzodiazepine receptor ligands. 1,3-Diarylpyrrole derivatives 1a-h show similar affinity and efficacy to that of diazepam, while the 1-aryltriazoles 2a,b have no receptor affinity. Comparison of the latter results with those on previously reported compounds suggests that there are several hydrophobic regions on the benzodiazepine recognition site whose occupation gives rise to different affinity and efficacy.

Animals↗
PubMed1990

Specific inhibition of benzodiazepine receptor binding by some N-(2-methyl or 1,2-dimethylindol-3-ylglyoxylyl)amino acid derivatives.

Several N-(2-methyl or 1,2-dimethylindol-3-ylglyoxylyl)amino acid derivatives were synthesized and tested for their affinity for the benzodiazepine receptor in bovine cortical membranes. The 2-methyl derivatives showed a lower affinity than the unmethylated analogues, and the 1,2-dimethyl derivatives practically lacked any affinity for the benzodiazepine receptor. The importance of the indole N-H group is therefore evidenced for an optimal interaction of these ligands with receptor site.

Amino Acids↗
PubMed1989

Tricyclic heteroaromatic systems: synthesis, [3H]flunitrazepam brain membrane binding inhibition, and structure-activity relationships of 2,3-dihydro-2-aryl-4-R-[1]benzopyrano[4,3-c]pyrazole-3-ones.

We report the synthesis and binding activity to the central benzodiazepine receptors of some 2,3-dihydro-2-aryl-4-R-[1]benzopyrano[4,3-c]pyrazole-3-ones, which are isosteres of the CGS series. Although the compounds of the CGS series are potent ligands of the benzodiazepine receptors, none of the isosteres tested showed any significant inhibiting potency. This may be due to the change in electronic properties brought about by the replacement of the NH of the CGS series with an oxygen atom.

Animals↗
PubMed1989

Synthesis of 1,5-diaryl-3-methyl-1H-pyrazolo[4,5-c]isoquinolines and studies of binding to specific peripheral benzodiazepine binding sites.

Some 1,5-diaryl-3-methyl-1H-pyrazolo[4,5-c]isoquinolines were synthesized and tested for their ability to displace [3H]clonazepam or [3H]Ro 5-4864 from their specific binding on the central and peripheral benzodiazepine receptors. None of the tested compounds showed any activity as central binding inhibitors, while most of them were specific as peripheral binding inhibitors, although they were not very potent.

Animals↗
PubMed1989

Binding of [3H] muscimol to the retina of rabbit and turtle.

1. We studied the binding of [3H]muscimol to membrane preparations of the retina of rabbit (Lepus cuniculus) and turtle (Pseudemys scripta elegans). 2. In both species, [3H]muscimol binding was maximal at 0 degrees C and decreased with increasing temperature, it was saturable, protein concentration dependent and specific. Muscimol, GABA and bicuculline were the most effective displacers, whereas baclofen and diaminobutyric acid were ineffective. 3. In the turtle retina, Scatchard analysis indicated the presence of a single site with a KD of 20.81 nM, and a Bmax of 3.620 pmol/mg prot. 4. In the rabbit, a single site could be identified in the nanomolar concentration range (KD of 12.8 nM, Bmax of 1.327). A study of the association rate of [3H]muscimol binding revealed a faster kinetics in turtle, as compared to rabbit.

Animals↗
PubMed1989

Specific inhibition of benzodiazepine receptor binding by some N-(indol-3-ylglyoxylyl)amino acid derivatives: stereoselective interactions.

Several optically active N-(indol-3-ylglyoxylyl)amino acid derivatives were synthesized and tested for [3H]flunitrazepam displacing activity in bovine brain membranes. IC50 values were measured and revealed that the D form of the amino acid moiety of the compounds was more potent than both the L form and racemic form, suggesting a key role of the amino acid stereochemistry on the affinity to the benzodiazepine receptors. GABA ratio and proconvulsant/convulsant data reported for the most active compounds reveal they behave as inverse agonists at the benzodiazepine receptor.

Amino Acids↗
PubMed1989

Further investigation on benzodiazepine binding inhibitory activity in patients with major depression or panic disorder and in healthy volunteers.

Preliminary findings regarding the presence of plasmatic benzodiazepine binding inhibitory activity (BBIA) in 14 psychiatric patients prompted us to investigate it further in larger samples of psychiatric patients (n = 44) and in healthy controls (n = 14). The results have shown that BBIA is present in all the subjects included with statistically significant differences between the patients and controls. The highest concentrations were found in the patients with no difference between anxious or depressed patients, and the lowest in the healthy controls. These findings indicate that BBIA might play a role in the pathophysiology of some manifestations of anxiety.

Adult↗
PubMed1989

Dipyrazolo[5,4-b:3',4'-d]pyridines. Synthesis, inhibition of benzodiazepine receptor binding and structure-activity relationships.

Some 2,6,8-trisubstituted dipyrazolo[5,4-b:3',4'-d]pyridin-3-ones related to the CGS series were synthesized and tested for their ability to displace [3H]flunitrazepam binding from bovine brain membranes. However the affinity for the benzodiazepine receptor of the tested compounds was lower than that of the CGS series, although it was comparable to that of chlordiazepoxide. It follows that some structure-activity relationships on the tested compounds can be drawn.

Animals↗
PubMed1987

A 3H-flunitrazepam binding inhibitor is present in psychiatric patients' sera.

We investigated the possible existence of endogenous compounds acting on benzodiazepine central receptors in the serum of patients with panic attacks or depression. Our results show the presence of a substance which inhibits the 3H-flunitrazepam binding specifically in the samples taken from the patients' groups, and which is not present in normal controls, in the range of concentrations used. This compound has a molecular weight below 1,000 daltons, is heat-stable, and resistant to proteolytic degradation. The demonstration of this inhibitor opens new perspectives in the study of the biochemistry of anxiety.

Adolescent↗
PubMed1983

Solubilization of rat kidney benzodiazepine binding sites.

The high-affinity binding site for [3H]Ro 5-4864 has been solubilized from rat kidney using 1% Triton X-100. After lowering the concentration of detergent and using a poly(ethylene glycol) gamma-globulin assay, it has been possible to demonstrate solubilization of about 90% of the binding sites. A single soluble class of binding sites with a Kd of 1.8 nM is found. The order of potency of benzodiazepines is identical for the solubilized receptor and the membrane-bound form. Gel filtration revealed a major peak of binding activity with apparent molecular weight of 215000 and a Stokes' radius of 5.03 nm.

Amphetamines↗