NESS002ie: a new fluorinated thiol endopeptidase inhibitor with antinociceptive activity in an animal model of persistent pain.

For the past few decades membrane zinc metallopeptidases have been identified as important therapeutic targets in the control of pain. In particular, neutral endopeptidase (NEP) has been shown to play critical roles in the metabolism of the endogenous peptides Met- and Leu-enkephalins. In this study, we have evaluated the activity of a new fluorinated peptidase inhibitor NESS002ie in both in vitro and in vivo assays. NESS002ie has been compared to the peptidomimetic compound thiorphan and the previously reported NEP selective thiol inhibitor C20. The metallopeptidases inhibitory activity of NESS002ie was tested in vitro using a highly, sensitive, continuous, fluorometric, enzyme assay. Also, the analgesic propriety of NESS002ie, thiorphan and C20 have been evaluated in vivo, by intraplantar, intravenous and intrathecal administration, through nociception assays based on formalin test in mice. Metallopeptidases assays have shown an inhibitory potency of NESS002ie in the nanomolar range for NEP and angiotensin-converting enzyme (ACE). The new fluorinated inhibitor showed higher analgesic activity and bioavailability compared to thiorphan and C20 when administered by both intravenous and intrathecal injections. More significantly, intrathecal injection of NESS002ie reduced both the first and the second phases of the formalin biphasic pain response. In addition, naltrindole and naloxone reversed the analgesic effect of NESS002ie with a diverse profile. This study shows an improvement in relief of inflammation and pain, in vivo, using NESS002ie compared to reference compounds thiorphan and C20. This significant effect could be due to the replacement of isobutyl chain of the thiol C20 with the trifluoromethyl group.

NESS06SM reduces body weight with an improved profile relative to SR141716A.

We have recently synthesized a new series of 4,5-dihydrobenzo-oxa-cycloheptapyrazole derivatives with the aim to discover novel CB1 antagonist agents characterized by anti-obesity activity comparable to that of SR141716A but with reduced adverse effects such as anxiety and depression. Within the novel class, the CB1 antagonist 8-chloro-1-(2,4-dichlorophenyl)-N-piperidin-1-yl-4,5-dihydrobenzo-1H-6-oxa-cyclohepta(1,2-c)pyrazole-3-carboxamide (NESS06SM) has been selected as lead compound. We found that NESS06SM is a CB1 neutral antagonist, characterized by poor blood-brain barrier permeability. Moreover, NESS06SM chronic treatment determined both anti-obesity effect and cardiovascular risk factor improvement in C57BL/6N Diet Induced Obesity (DIO) mice fed with fat diet (FD mice). In fact, the mRNA gene expression in Central Nervous System (CNS) and peripheral tissues by real time PCR, showed a significant increase of orexigenic peptides and a decrease of anorexigenic peptides elicited by NESS06SM treatment, compared to control mice fed with the same diet. Moreover, in contrast to SR141716A treatment, the chronic administration of NESS06SM did not change mRNA expression of both monoaminergic transporters and neurotrophins highly related with anxiety and mood disorders. Our results suggest that NESS06SM reduces body weight and it can restore the disrupted expression profile of genes linked to the hunger-satiety circuit without altering monoaminergic transmission probably avoiding SR141716A side effects. Therefore the novel CB1 neutral antagonist could represent a useful candidate agent for the treatment of obesity and its metabolic complications.

Synthesis and pharmacological evaluation of novel 4-alkyl-5-thien-2'-yl pyrazole carboxamides.

The synthesis of three series of novel 4-alkyl-5-(5'-chlorothiophen-2'-yl)-pyrazole-3-carbamoyl analogues of rimonabant with affinity for the CB1 cannabinoid receptor subtype is reported. Amongst the novel derivatives, compounds 21j, 22a, 22c, and 22f showed affinity values expressed as Ki ranging from 5.5 to 9.0 nM. Derivative 23e revealed a good CB1 affinity (K(i) = 11.7 nM) and the highest CB1 selectivity of the whole series (K(i)CB2/K(i)CB1 = 384.6). These new compounds appeared to be able to pass the blood brain barrier and to counteract the activity of cannabinoid agonist. According to the results of mice vas deferens assays, as in the case of rimonabant, derivatives 21a, 22a, and 22b showed inverse agonist activity. In contrast, as a preliminary result to be confirmed, compound 23a exhibited neutral antagonist profile. According to the data obtained through an acute animal model, selected compounds 21a, 22a, and 23a evidenced the capability to significantly reduce food intake. At specific conditions, the effect of the novel compounds were higher than that induced by rimonabant. Amongst the novel CB1 antagonist compounds, 23a may represent a useful candidate agent for the treatment of obesity and its metabolic complications, with reduced side effects relative to those instead observed with rimonabant.

Nasal continuous positive airway pressure (CPAP) versus bi-level nasal CPAP in preterm babies with respiratory distress syndrome: a randomised control trial.

OBJECTIVE: To evaluate the clinical course, respiratory outcomes and markers of inflammation in preterm infants with moderate respiratory distress syndrome (RDS) assigned from birth to nasal continuous positive airway pressure (NCPAP) or bi-level NCPAP. METHODS: A total of 40 infants with a gestational age (GA) of 28-34 weeks (<35 weeks' GA), affected by moderate RDS, were considered eligible and were randomised to NCPAP (group A; n=20, CPAP level=6 cm H(2)O) or to bi-level NCPAP (group B; n=20, lower CPAP level=4.5 cm H(2)O, higher CPAP level=8 cm H(2)O), provided with variable flow devices. Inflammatory response was the primary outcome; serum cytokines were measured on days 1 and 7 of life. Length of ventilation, oxygen dependency, need for intubation and occurrence of air leaks were considered as secondary outcomes. RESULTS: Infants showed similar characteristics at birth (group A vs group B: GA 30.3+/-2 vs 30.2+/-2 weeks, birth weight 1429+/-545 vs 1411+/-560 g) and showed similar serum cytokine levels at all times. Group A underwent longer respiratory support (6.2+/-2 days vs 3.8+/-1 days, p=0.025), longer O(2) dependency (13.8+/-8 days vs 6.5+/-4 days, p=0.027) and was discharged later (GA at discharge 36.7+/-2.5 weeks vs 35.6+/-1.2 weeks, p=0.02). All infants survived. No bronchopulmonary dysplasia (BPD) or neurological disorders occurred. CONCLUSIONS: Bi-level NCPAP was associated with better respiratory outcomes versus NCPAP, and allowed earlier discharge, inducing the same changes in the cytokine levels. It was found to be well tolerated and safe in the study population.

Lung inflammation in preterm infants with respiratory distress syndrome: effects of ventilation with different tidal volumes.

Ventilation with an inappropriate tidal volume (Vt) triggers lung inflammation, an important predisposing factor of bronchopulmonary dysplasia. It still remains uncertain what the appropriate starting target Vt should be during the acute phase of respiratory distress syndrome (RDS). Our aim was to evaluate lung inflammation in preterm infants undergoing synchronized intermittent positive-pressure ventilation (SIPPV) with two different tidal volumes Vt during the acute phase of RDS. Thirty preterm infants (gestational age, 25-32 weeks) with acute RDS were randomly assigned to be ventilated with Vt = 5 ml/kg (n = 15) or Vt = 3 ml/kg (n = 15). Proinflammatory cytokines (interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor (TNF)-alpha) were determined in the tracheal aspirate on days 1, 3, and 7 of life. IL-8 and TNF-alpha levels collected on day 7 were significantly higher (P < 0.05), and mechanical ventilation lasted longer in the group with Vt = 3 ml/kg (16.8 +/- 4 vs. 9.2 +/- 4 days; P = 0.05). In conclusion, our data show significantly higher lung inflammation in preterm infants ventilated with Vt = 3 ml/kg, suggesting a role for Vt = 5 ml/kg in reducing both inflammatory response during the acute phase of RDS and the length of ventilation. Whether the use of this starting Vt prevents bronchopulmonary dysplasia requires further study.

Tricyclic pyrazoles. 3. Synthesis, biological evaluation, and molecular modeling of analogues of the cannabinoid antagonist 8-chloro-1-(2',4'-dichlorophenyl)-N-piperidin-1-yl-1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c]pyrazole-3-carboxamide.

A series of analogues of 8-chloro-1-(2',4'-dichlorophenyl)-N-piperidin-1-yl-1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c]pyrazole-3-carboxamide 4a (NESS 0327) (Ruiu, S.; Pinna, G. A.; Marchese, G.; Mussinu, J. M.; Saba, P.; Tambaro, S.; Casti, P.; Vargiu, R.; Pani, L. Synthesis and Characterization of NESS 0327: A Novel Putative Antagonist of CB1 Cannabinoid Receptor. J. Pharmacol. Exp. Ther. 2003, 306, 363-370) was synthesized and evaluated for their affinity to cannabinoid receptors. Depending on the chemical modification of the lead structure that was chosen, compounds 4b, 4c, 4i, 4l, and 4m still proved to be potent binders of the CB1 receptor. Moreover, several analogues (4c, 4d, 4e, and 4m) demonstrated superior CB2 receptor binding affinities compared to the parent ligand. Compounds 4b, 4c, 4i, and 4l displayed the most promising pharmacological profiles, having the highest selectivity for CB1 receptors with Ki(CB2) to Ki(CB1) ratios of 11,250, 2000, 3330 and 4625, respectively. Compound 4c increased the intestinal propulsion in mice and antagonized the effect induced by the CB1 receptor agonist WIN 55,212-2. Finally, molecular modeling studies were carried out on a set of tricyclic pyrazoles (2a-4a) and on rimonabant 1 (SR141716A), indicating that high CB1 receptors affinities were consistent for the tricyclic derivatives, both with a nonplanar geometry of the tricyclic cores and with a precise orientation of the substituent (chlorine) on this ring system.

Differential distribution of functional cannabinoid CB1 receptors in the mouse gastroenteric tract.

Recently, the gastrointestinal pharmacology of cannabinoid CB(1) receptors has been extensively explored. We employed western blotting and immunohistochemistry techniques to study the distribution of the cannabinoid CB(1) receptor protein in the mouse gastroenteric tract. The cannabinoid CB(1) receptor peptide was detected by western blotting only in its glycosylated form (63 kDa) with a significant differential distribution. The highest levels of expression were detected in the stomach and in the colon, while the pyloric valve was devoid of any cannabinoid CB(1) receptor protein. The immunohistochemical study showed intense cannabinoid CB(1) receptor immunoreactivity in ganglia subadjacent to the gastric epithelium and in the smooth muscle layers of both the small and large intestine. Only the small intestine showed (-)-3-[2-hydroxyl-4-(1,1-dimethylheptyl)-phenyl]-4-(3-hydroxylpropyl) cyclohexan-1-ol) ([3H]CP 55,940) specific binding (27%). These receptors mediated pharmacologically significant effects since the cannabinoid CB(1) receptor agonist R(-)-7-hydroxy-delta-6-tetra-hydrocannabinol-dimethylheptyl (HU 210) dose dependently inhibited gastrointestinal transit up to 70%, while the cannabinoid CB(1) receptor antagonist N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide (SR 141716A) increased gastrointestinal transit. Moreover, the dose of 0.3 microg/kg of HU 210, devoid per se of any activity on mouse intestinal propulsion, blocked the increased gastroenteric transit induced by the cannabinoid CB(1) antagonist SR 141716A.

GABA(B)-receptor mediation of the inhibitory effect of gamma-hydroxybutyric acid on intestinal motility in mice.

The effect of acutely administered gamma-hydroxybutyric acid (GHB) and GHB receptor antagonist, NCS-382, on the propulsive activity in the mouse small intestine was assessed by measuring the transit of an orally administered, non absorbable marker. Both GHB (0, 25, 50, 100, 200 and 300 mg/kg; i.p.) and NCS-382 (0, 25, 50 and 75 mg/kg; i.p.) induced a dose-dependent inhibition (up to 50-60%) of the marker transit. Pretreatment with the GABA(B) receptor antagonist, SCH 50911 (100 mg/kg; i.p.), resulted in the blockade of the inhibiting effect of both GHB and NCS-382. These results suggest that the constipating effect of GHB and NCS-382 are secondary to stimulation of the GABA(B) receptor.

Central effects of 1,4-butanediol are mediated by GABA(B) receptors via its conversion into gamma-hydroxybutyric acid.

The aliphatic alcohol 1,4-butanediol in converted into gamma-hydroxybutyric acid (GHB) via two enzymatic steps: first, it is oxidised by alcohol dehydrogenase in gamma-hydroxybutyraldehyde; second, the latter is transformed, likely by aldehyde dehydrogenase, into GHB. Initially, the present study compared the sedative/hypnotic effect of GHB and 1,4-butanediol, measured as loss of righting reflex. 1,4-Butanediol was more potent than GHB, presumably because of a more rapid penetration of the blood brain barrier. Further alcohol dehydrogenase inhibitors, 4-methylpyrazole and ethanol, totally prevented the sedative/hypnotic effect of 1,4-butanediol; the aldehyde dehydrogenase inhibitor disulfiram partially blocked the sedative/hypnotic effect of 1,4-butanediol. Finally, the sedative/hypnotic effect of 1,4-butanediol was antagonised by the GABA(B) receptor antagonists, SCH 50911 [(2S)(+)-5,5-dimethyl-2-morpholineacetic acid] and CGP 46381 [(3-aminopropyl)(cyclohexylmethyl)phosphinic acid], but not by the putative GHB receptor antagonist NCS-382 (6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylideneacetic acid), indicating that it is mediated by GABA(B) but not GHB receptors. Taken together, these results suggest that the sedative/hypnotic effect of 1,4-butanediol is mediated by its conversion in vivo into GHB which, in turn, binds to GABA(B) receptors. Accordingly 1,4-butanediol, unlike GHB, failed to displace [(3)H]GHB and [(3)H]baclofen in brain membranes.