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Due to the neuroprotective role of the Na+/Ca2+ exchanger (NCX) isoforms NCX1 and NCX3, we synthesized novel benzodiazepinone derivatives of the unique NCX activator Neurounina-1, named compounds 1-19. The derivatives are characterized by a benzodiazepinonic nucleus linked to five- or six-membered cyclic amines via a methylene, ethylene, or acetyl spacer. The compounds have been screened on NCX1/NCX3 isoform activities by a high-throughput screening approach, and the most promising were characterized by patch-clamp electrophysiology and Fura-2AM video imaging. We identified two novel modulators of NCX: compound 4, inhibiting NCX1 reverse mode, and compound 14, enhancing NCX1 and NCX3 activity. Compound 1 displayed neuroprotection in two preclinical models of brain ischemia. The analysis of the conformational and steric features led to the identification of the molecular volume required for selective NCX1 activation for mixed NCX1/NCX3 activation or for NCX1 inhibition, providing the first prototypal model for the design of optimized isoform modulators.

Introduction The gasotransmitter hydrogen sulphide (H2S), an endogenous ubiquitous signalling molecule, is known for its beneficial effects on different mammalian systems. H2S exhibits cardioprotective activity against ischemia/reperfusion (I/R) or hypoxic injury. Methods A library of forty-five isothiocyanates, selected for their different chemical properties, has been evaluated for its hydrogen sulfide (H2S) releasing capacity. The obtained results allowed to correlate several factors such as steric hindrance, electronic effects and position of the substituents to the observed H2S production. Moreover, the chemical-physical profiles of the selected compounds have been studied by an in silico approach and from a combination of the obtained results, 3-pyridyl-isothiocyanate (25) has been selected as the most promising one. A detailed pharmacological characterization of its cardioprotective action has been performed. Results The results herein obtained strongly indicate 3-pyridyl-isothiocyanate (25) as a suitable pharmacological option in anti-ischemic therapy. The cardioprotective effects of compound 25 were tested in vivo and found to exhibit a positive effect. Conclusion Results strongly suggest that isothiocyanate-based H2S-releasing drugs, such as compound 25, can trigger a ‘‘pharmacological pre-conditioning” and could represent a suitable pharmacological option in antiischemic therapy.

Background: Serotonin is an important biogenic amine and is implicated in wideranging physiological and physiopathological processes. Pharmacological manipulation of the serotoninergic system is believed to have a great therapeutic potential. Objectives: In order to identify selective ligands for 5-HT1A, 5-HT2A and 5-HT2C receptors two series of 4-substituted piperazine derivatives, bearing indolic or methyl indolic nuclei, were synthesized. Methods: All the compounds, synthesized by standard solution methods, were evaluated for 5- HT1A, 5-HT2A and 5-HT2C receptors. The highest affine and selective compounds have been evaluated also on dopaminergic (D1 and D2) and adrenergic (α1A and α2A) receptors. Results: Several of the newly synthesized molecules showed affinity in the nanomolar range for 5- HT1A, 5-HT2A and 5-HT2C receptors and moderate to no affinity for other relevant receptors (D1, D2, α1A and α2A). Conclusion: Compounds 7f and 10a showed a nanomolar affinity towards 5-HT1A with an in vitro pharmacologic profile compatible with antipsychotic drugs.

Graphical abstract, Highlights • Hydrogen sulfide is a fundamental endogenous gas-mediator in the respiratory system. • Design and synthesis of SAIDs-hydrogen sulfide donors hybrids are described. • Hydrogen sulfide release and chemical stability at differing pH were investigated. • Prednisone-TBZ hybrid (compound 7) was selected for further evaluations. • Prednisone-TBZ is a promising therapeutic option in allergic asthma treatment., Introduction Hydrogen sulfide (H2S) is a fundamental biological endogenous gas-mediator in the respiratory system. It regulates pivotal patho-physiological processes such as oxidative stress, pulmonary circulation, airway tone and inflammation. Objectives We herein describe the design and synthesis of molecular hybrids obtained by the condensation of several corticosteroids with different hydrogen sulfide releasing moieties. Methods All the molecules are characterized for their ability to release H2S both via amperometric approach and using a fluorescent probe. The chemical stability of the newly synthesized hybrid molecules has been investigated at differing pH values and in human serum. Results Prednisone-TBZ hybrid (compound 7) was selected for further evaluations. The obtained results from the in vitro and in vivo studies clearly show evidence in favor of the anti-inflammatory properties of the released H2S. Conclusions The protective effect on airway remodeling makes the hybrid Prednisone-TBZ (compound 7) as a promising therapeutic option in reducing allergic asthma symptoms and exacerbations.

S1P is the final product of sphingolipid metabolism, which interacts with five widely expressed GPCRs (S1P1-5). Increasing numbers of studies have indicated the importance of S1P3 in various pathophysiological processes. Recently, we have identified a pepducin (compound KRX-725-II) acting as an S1P3 receptor antagonist. Here, aiming to optimize the activity and selectivity profile of the described compound, we have synthesized a series of derivatives in which Tyr, in position 4, has been substituted with several natural aromatic and unnatural aromatic and non-aromatic amino acids. All the compounds were evaluated for their ability to inhibit vascular relaxation induced by KRX-725 (as S1P3 selective pepducin agonist) and KRX-722 (an S1P1-selective pepducin agonist). Those selective towards S1P3 (compounds V and VII) were also evaluated for their ability to inhibit skeletal muscle fibrosis. Finally, molecular dynamics simulations were performed to derive information on the preferred conformations of selective and unselective antagonists.

Neurounina-1 [chemical name: 7-nitro-5-phenyl-1-(pyrrolidin-1-ylmethyl)-1H-benzo[e][1,4]diazepin-2(3H)-one] is a new compound provided with relevant neuroprotective effect during stroke and in neonatal hypoxia by increasing the Na+/Ca2+ exchanger (NCX) isoforms NCX1 and NCX2 activity. This study shows for the first time, the development and validation of a sensitive and selective method for analysis of neurounina-1 in beagle dog plasma by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The sample preparation consisted of extraction of the analyte and the internal standard (IS) (ropivacaine) from plasma (50 μL) by liquid-liquid extraction using acetonitrile (100 μL). The selected reaction monitoring mode of the positive ion was performed and the precursor to the product ion transitions of m/z 365 > 83 and m/z 275 > 126 were used to measure the derivative of neurounina-1 and ropivacaine. The chromatographic separation was achieved using a Phenomenex C18 Luna (150 mm × 4.6 mm × 5 μm) analytical column with an isocratic mobile phase composed of methanol/acetonitrile/water (50/40/10, v/v/v) + 0.1% formic acid + 1 M ammonium formate. The method was linear over a concentration range of 1–500 ng/mL. The method was applied to evaluate the pharmacokinetics of neurounina-1 after a single intravenous administration of three different doses (0.1 mg/kg, 0.3 mg/kg, and 1 mg/kg) to beagle dogs (n = 5). The mean AUC0-tlast values were 26.10, 115.81, and 257.28 ng∗h/mL following intravenous administration of 0.1, 0.3, and 1 mg/kg, respectively. Linear pharmacokinetics was observed up to 1.0 mg/kg. The neurounina-1 was rapidly eliminated, with mean CL values of 46.24, 47.57, and 69.15 L/h, Vd of 130.31, 154.15, and 210.79 L and t1/2 of 2.14, 2.54, and 2.04 h after intravenous administration of 0.1, 0.3, and 1 mg/kg, respectively. This new analytical method allows the rapid determination of the neurounina-1, a new developed compound, able to exert a remarkable neuroprotective effect in the low nanomolar range.

A new series of norbornene and exo-N-hydroxy-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximide derivatives was prepared, and their affinities to the 5-HT1A , 5-HT2A , and 5-HT2C receptors were evaluated and compared with a previously synthesized series of derivatives characterized by the same nuclei, to identify selective ligands for the subtype receptors. Arylpiperazines represent one of the most important classes of 5-HT1A R ligands, and the research of new derivatives has been focused on the modification of one or more portions of this pharmacophore. The combination of structural elements (heterocyclic nucleus, hydroxyalkyl chain, and 4-substituted piperazine), known to be critical for the affinity to 5-HT1A receptors, and the proper selection of substituents resulted in compounds with high specificity and affinity toward serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that 3e, 4j, and 4n were the most active and promising derivatives for the serotonin receptor considered in this study.

The combination of medroxyprogesterone acetate 25 mg + estradiol cypionate 5 mg is a highly effective, monthly injectable contraceptive. For the first time, this study presents the development and validation of a sensitive method for estradiol cypionate analysis in human plasma by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Aliquots (500 μL) of plasma were extracted with ethyl ether (100%) and derivatized with dansyl chloride. Its separation was performed on a Jones Chromatography Genesis C8 column and the quantification was performed with a mass spectrometer equipped with an electrospray interface operating in negative ion mode. The run time was 6 min and the calibration curve was linear over the range of 0.005−0.15 ng/mL. The method was applied to evaluate the pharmacokinetics of estradiol cypionate in plasma collected up to 1008 h (42 days) after a single intramuscular administration of 25 mg/mL medroxyprogesterone acetate +5 mg/mL estradiol cypionate to healthy female volunteers (n = 12). The estradiol cypionate maximum plasma concentration (Cmax) was 0.14 ± 0.08 ng/mL reached at 16.83 ± 21.07 h and the area under the plasma concentration versus time curve (AUC0-last) was 14.07 ± 6.32 ng.h/mL. Elimination half-life (t½), apparent volume of distribution (Vd/F), apparent clearance (CL/F) and mean residence time (MRT) were 89.65 ± 76.04 h, 28038 ± 9636 L, 49.02 ± 10.62 L/h and 576.05 ± 238.32 h, respectively, showing that the estradiol cypionate release from the administration site was prolonged and there was no drug accumulation.

Peptide T (ASTTTNYT), a fragment corresponding to residues 185-192 of gp120, the coat protein of HIV, is endowed with several biological properties in vitro, notably inhibition of the binding of both isolated gp120 and HIV-1 to the CD4 receptor, and chemotactic activity. Based on previous nuclear magnetic resonance (NMR) studies performed in our laboratory, which were consistent with a regular conformation of the C-terminal pentapeptide, and SAR studies showing that the C-terminal pentapeptide retains most of the biological properties, we designed eight hexapeptides containing in the central part either the TNYT or the TTNY sequence, and charged residues (D/E/R) at the two ends. Conformational analysis based on NMR and torsion angle dynamics showed that all peptides assume folded conformations, albeit with different geometries and stabilities. In particular, peptides carrying an acidic residue at the N-terminus and a basic residue at the C-terminus are characterized by stable helical structures and retain full chemotactic activity. The solution conformation of peptide ETNYTR displays strong structural similarity to the region 19-26 of both bovine pancreatic and bovine seminal ribonuclease, which are endowed with anti-HIV activity. Moreover, the frequent occurrence, in many viral proteins, of TNYT and TTNY, the two core sequences employed in the design of the hexapeptides studied in the present work, hints that the sequence of the C-terminal pentapeptide TTNYT is probably representative of a widespread viral recognition motif. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.

Cell-penetrating peptides are able to transport covalently attached cargoes such as peptide or polypeptide fragments of endogenous proteins across cell membranes. Taking advantage of the cell-penetrating properties of the 16-residue fragment penetratin, we synthesized a chimeric peptide that possesses an N-terminal sequence with membrane-penetrating activity and a C-terminal sequence corresponding to the last 21 residues of G alpha(s). This G alpha(s) peptide was an effective inhibitor of 5'-N-ethylcarboxamidoadenosine (NECA) and isoproterenol-stimulated production of cAMP in rat PC12 and human microvascular endothelial (HMEC-1) cells, whereas the carrier peptide had no effect. The maximal efficacy of NECA was substantially reduced when PC12 cells were treated with the chimeric peptide, suggesting that it competes with G alpha(s) for interaction with receptors. The peptide inhibited neither G(q)- nor G(i)-coupled receptor signaling. The use of a carboxy-fluorescein derivative of the peptide proved its ability to cross the plasma membrane of live cells. NMR analysis of the chimeric peptide structure in a membrane-mimicking environment showed that the G alpha(s) fragment assumed an amphipathic alpha-helical conformation tailored to make contact with key residues on the intracellular side of the receptor. The N-terminal penetratin portion of the molecule also showed an alpha-helical structure, but hydrophobic and hydrophilic residues formed clustered surfaces at the N terminus and center of the fragment, suggesting their involvement in the mechanism of penetratin internalization by endocytosis. Our biological data supported by NMR analysis indicate that the membrane-permeable G alpha(s) peptide is a valuable, nontoxic research tool to modulate G(s)-coupled receptor signal transduction in cell culture models.

Protease-activated receptor-2 (PAR-2) is a member of seven transmembrane domain G protein-coupled receptors activated by proteolytic cleavage whose better known member is the thrombin receptor. The pathophysiological role of PAR-2 remains poorly understood. Because PAR-2 is involved in inflammatory and injury response events, we investigated the role of PAR-2 in experimental myocardial ischemia-reperfusion injury. We show for the first time that PAR-2 activation protects against reperfusion-injury. After PAR-2-activating peptide (2AP) infusion, we found a significant recovery of myocardial function and decrease in oxidation at reflow. Indeed, the glutathione cycle (glutathione and oxidized glutathione) and lipid peroxidation analysis showed a reduced oxidative reperfusion-injury. Moreover, ischemic risk zone and creatine kinase release were decreased after PAR-2AP treatment. These events were coupled to elevation of PAR-2 and tumor necrosis factor α (TNFα) expression in both nuclear extracts and whole heart homogenates. The recovery of coronary flow was not reverted by L-nitroarginine methylester, indicating a NO-independent pathway for this effect. Genistein, a tyrosine kinase inhibitor, did not revert the PAR-2AP effect. During early reperfusion injury in vivo not only oxygen radicals are produced but also numerous proinflammatory mediators promoting neutrophil and monocyte targeting. In this context, we show that TNFα and PAR-2 are involved in signaling in pathophysiological conditions, such as myocardial ischemia-reperfusion. At the same time, because TNFα may exert pro-inflammatory actions and PAR-2 may constitute one of the first protective mechanisms that signals a primary inflammatory response, our data support the concept that this network may regulate body responses to tissue injury.

With the aim of discovering new molecules with K + -channel activating properties, we have synthesized derivatives of cromakalim (CRK), an important molecule which shows specific affinity towards K + channels, by replacing the benzopyrane ring of this reference compound with a 1,4-benzoxazine moiety. A different number of substituents showing a good discrimination between hydrophobic and electronic properties have been inserted at the 6-position of the 1,4-benzoxazine ring. We describe here the synthesis and discuss the solid state conformation of these new molecules. When tested on rat aorta ring precontracted with phenylephrine, two compounds ( 2c and 2d ) showed a concentration-dependent relaxation similar to that measured for cromakalim but less potent than this reference drug.

A thorough investigation on the dependence of distribution coefficients of acidic drugs on pH and pKa values has been carried out. The results give evidence that the Henderson‐Hasselbach equation is an idealization and only an approximation for real systems. It is shown that a multiparametric curve‐fitting technique may constitute a useful alternative to the previously reported methods to describe the hydrophilic/lipophilic pH‐profiles of ionogenic substances. Calculated values at any given pH value are in very good agreement with the experimental partition (log P) and distribution coefficients determined by shake‐flask method and reversed‐phase high performance liquid chromatography. Copyright © 1986 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim

SPECIFIC AIMSTo clarify the role played by protease activated receptors 1 and 2 (PAR-1 and PAR-2) in the control of blood pressure, we have evaluated changes in blood pressure induced by a peptide activating the receptor PAR-1 (PAR-1AP, SFLLRNPND) and a peptide activating the receptor PAR-2 (PAR-2AP, SLIGRL) in naive and ganglion-blocked anesthetized rats. To investigate the role played by nitric oxide (NO), the effect of PAR-1AP and PAR-2AP in ganglion-blocked rats was evaluated before and after L-NAME administration.PRINCIPAL FINDINGS1. Both PAR-1AP and PAR-2AP cause a biphasic change in MABP in ratsIntravenous (i.v.) injection of PAR-1AP (1 mg/kg) into naive anesthetized rats caused a biphasic response characterized by hypotension (13±2 mmHg; n=6), immediately followed by hypertension (21±3 mmHg; n=6), returning to baseline value in 3 min; i.v. injection of PAR-2AP (1 mg/kg) caused a hypotension (28±5 mmHg; n=5) lasting about 2 min. Hypotension was followed by a slowly developing hypertension, reaching...