863 research outputs found
Recent Advances on Anilato-Based Molecular Materials with Magnetic and/or Conducting Properties
No full textThe aim of the present work is to highlight the unique role of anilato-ligands, derivatives of the 2,5-dioxy-1,4-benzoquinone framework containing various substituents at the 3 and 6 positions (X = H, Cl, Br, I, CN, etc.), in engineering a great variety of new materials showing peculiar magnetic and/or conducting properties. Homoleptic anilato-based molecular building blocks and related materials will be discussed. Selected examples of such materials, spanning from graphene-related layered magnetic materials to intercalated supramolecular arrays, ferromagnetic 3D monometallic lanthanoid assemblies, multifunctional materials with coexistence of magnetic/conducting properties and/or chirality and multifunctional metal-organic frameworks (MOFs) will be discussed herein. The influence of (i) the electronic nature of the X substituents and (ii) intermolecular interactions i.e., H-Bonding, Halogen-Bonding, π-π stacking and dipolar interactions, on the physical properties of the resulting material will be also highlighted. A combined structural/physical properties analysis will be reported to provide an effective tool for designing novel anilate-based supramolecular architectures showing improved and/or novel physical properties. The role of the molecular approach in this context is pointed out as well, since it enables the chemical design of the molecular building blocks being suitable for self-assembly to form supramolecular structures with the desired interactions and physical propertie
Inhibition by the neurosteroid allopregnanolone of basal and stress-induced acetylcoline release in the brain of freely moving rats
No full textEffect of A1 receptor agonist and antagonist on hippocampal acetylcholine release in freely moving rats.
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Inhibition of basal and stress-induced dopamine release in the cerebral cortex and nucleus accumbens of freely moving rats by the neurosteroid allopregnanolone
No full textThe neurosteroid allopregnanolone is a potent and efficacious modulator of gamma-aminobutyric acid (GABA) type A receptors. The effects of intracerebroventricular injection of allopregnanolone (5 to 15 mu g in 5 mu l) on basal and stress-induced changes in the extracellular concentrations of dopamine were investigated by microdialysis in various brain areas of freely moving rats and compared with those of the benzodiazepine midazolam (1 to 10 mu g in 5 mu l). Allopregnanolone reduced (by a maximum of 65 to 75%) basal dopamine content in the prefrontal cortex and nucleus accumbens in a dose-dependent manner, but had no effect on dopamine output in the striatum. Allopregnanolone (10 to 15 mu g) also completely prevented the increase in extracellular dopamine concentrations in the nucleus accumbens and cerebral cortex induced by foot-shock stress. Midazolam reduced basal dopamine content in all three brain regions studied as well as the stress-induced increase in dopamine content in the nucleus accumbens and cerebral cortex with a greater potency than allopregnanolone. These results suggest that endogenous neurosteroids may participate in the GABAergic modulation of dopaminergic transmission in the rat cerebral cortex and nucleus accumbens, two brain areas which are important in the regulation of emotional processes. These agents do not appear to affect striatal dopaminergic transmission which modulates motor function
Anticonvulsant Doses of 2-Chloro-N6-Cyclopentyladenosine, an Adenosine A1 Receptor Agonist, Reduce GABAergic Transmission in Different Areas of the Mouse Brain.
No full textThe possible relationship between A1 adenosine receptors and the gamma-aminobutyric acid (GABAA) receptor complex was evaluated in the mouse brain. We studied the effect of in vitro addition and in vivo administration of 2-chloro-N6-cyclopentyladenosine (CCPA), the most selective ligand for A1 receptors, on the biochemical parameters used currently to evaluate GABAergic function. In vitro, CCPA (0.01-100 microM) failed to modify [3H] GABA binding, [3H]flunitrazepam binding, t-[35S]butylbicyclophosphorothionate ([35S]TBPS) binding and muscimol-stimulated 36Cl- uptake. On the contrary, in vivo, CCPA (1.4-27.6 mumol/kg i.p.) increased [35S]TBPS binding in membranes from the cerebral cortex, hippocampus, striatum and substantia nigra, but not from the cerebellum, thalamus, hypothalamus and olfactory tubercle. The specific A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxantine (9.8 mumol/kg i.p.) abolished the effect of CCPA on [35S]TBPS binding, indicating that the action of this compound is mediated by its interaction with A1 receptors. Diazepam (1.7 mumol/kg i.p.), a positive modulator of GABAergic transmission, antagonized the increase of [35S]TBPS binding induced by CCPA. CCPA (2.8-8.3 mumol/kg i.p.) antagonized convulsions induced by isoniazid, an inhibitor of GABA synthesis, but neither antagonized nor potentiated isoniazid-induced increase of [35S]TBPS binding. CCPA (2.8-8.3 mumol/kg i.p.) antagonized the convulsions induced by pentylenetetrazol (398 mumol/kg i.p.), methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (50 mumol/kg i.p.) and bicuculline methiodide (9.8 mumol/kg i.p.). The results show that, in spite of its anticonvulsant activity, CCPA reduces the function of the GABA-coupled chloride channel function. This finding suggests that the anticonvulsant target sites are different from those involved in the action of CCPA on GABAA receptors
DECREASED ALLOPREGNANOLONE INDUCED BY NEONATAL ESTRADIOL INCREASES α4βδ GABAA RECEPTORS, STRESS SENSITIVITY AND SPATIAL LEARNING IN ADULT FEMALE RATS
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