Identification and characterization of NDT 9513727 [N,N-bis(1,3-benzodioxol-5-ylmethyl)-1-butyl-2,4-diphenyl-1H-imidazole-5-methanamine], a novel, orally bioavailable C5a receptor inverse agonist.

The complement system represents an innate immune mechanism of host defense that has three effector arms, the C3a receptor, the C5a receptor (C5aR), and the membrane attack complex. Because of its inflammatory and immune-enhancing properties, the biological activity of C5a and its classical receptor have been widely studied. Because specific antagonism of the C5aR could have therapeutic benefit without affecting the protective immune response, the C5aR continues to be a promising target for pharmaceutical research.

1H-Pyrazolo-[3,4-c]cyclophepta[1,2-c]thiophenes: a unique structural class of dopamine D4 selective ligands.

A series of novel 1H-pyrazolo-[3,4-c]cyclophepta[1,2-c]thiophenes was prepared and screened at selected dopamine receptor subtypes. Compound 4 (NGB 4420) displayed high affinity and selectivity (>100-fold) for the D(4) over D(2) and other CNS receptors. This compound was identified as a D(4) antagonist via its attenuation of dopamine agonist-induced GTPgamma(35)S binding at D(4) receptor.

Design, synthesis, and discovery of 5-piperazinyl-1,2,6,7-tetrahydro-5H-azepino[3,2,1-hi]indol-4-one derivatives: a novel series of mixed dopamine D2/D4 receptor antagonist.

5-piperazinyl-1,2,6,7-tetrahydro-5H-azepino[3,2,1-hi]indol-4-one derivatives were designed, synthesized, and identified as a new series of mixed dopamine D(2)/D(4) receptor antagonists. This series featured a rigid tricyclic ring system as an important pharmacophore core structure for high binding affinity. Molecular modeling studies are also described.

Indoline and piperazine containing derivatives as a novel class of mixed D(2)/D(4) receptor antagonists. Part 2: asymmetric synthesis and biological evaluation.

A series of chiral benzylpiperazinyl-1-(2,3-dihydro-indol-1-yl)ethanone derivatives were prepared and examined for their affinity at dopamine D(2) and D(4) receptors. Three compounds having D(2)/D(4) affinity ratios approximating that found for the atypical neuroleptic clozapine were further evaluated in behavioral tests of antipsychotic efficacy and motor side effects.

Indoline and piperazine containing derivatives as a novel class of mixed D(2)/D(4) receptor antagonists. Part 1: identification and structure-activity relationships.

Optimization of the lead compound 2-[-4-(4-chloro-benzyl)-piperazin-1-yl]-1-(2,3-dihydro-indol-1-yl)-ethanone 1 by systematic structure-activity relation (SAR) studies lead to two potent compounds 2-[-4-(4-chloro-benzyl)-piperazin-1-yl]-1-(2-methy-2,3-dihydro-indol-1-yl)-ethanone 2n and 2-[-4-(4-chloro-benzyl)-piperazin-1-yl]-1-(2-methy-2,3-dihydro-indol-1-yl)-ethanone 7b. Their related synthesis was also reported.

6-(4-Benzylpiperazin-1-yl)benzodioxanes as selective ligands at cloned primate dopamine D(4) receptors.

A series of novel 6-(4-benzylpiperazin-1-yl)benzodioxanes were prepared and screened at selected dopamine receptor subtypes. 6-(4-[4-Chlorobenzyl]piperazin-1-yl)benzodioxane (2d) had high affinity and selectivity for the D(4) dopamine receptor subtype and was identified as a D(4) antagonist via its attenuation of dopamine-induced GTPgamma(35)S binding at the D(4) receptor.

Design and synthesis of [(2,3-dichlorophenyl)piperazin-1-yl]alkylfluorenylcarboxamides as novel ligands selective for the dopamine D3 receptor subtype.

The dopamine D3 receptor subtype has been recently targeted as a potential neurochemical modulator of the behavioral actions of psychomotor stimulants, such as cocaine. However, definitive behavioral investigations have been hampered by the lack of highly selective D3 agonists and antagonists. In an attempt to design a novel class of D3 ligands with which to study this receptor system, a series of chemically divergent compounds that possessed various structural features that exist within several classes of reputed D3 agents was screened and compared to the recently reported NGB 2904 (58b).

trans-1-[(2-Phenylcyclopropyl)methyl]-4-arylpiperazines: mixed dopamine D(2)/D(4) receptor antagonists as potential antipsychotic agents.

The dopaminergic receptor profile of a series of trans-1-[(2-phenylcyclopropyl)methyl]-4-arylpiperazines was examined. Aromatic substitution patterns were varied with the goal of identifying a compound having affinities for the D(2) and D(4) receptors in a ratio similar to that observed for the atypical neuroleptic clozapine. The compounds (1S, 2S)-trans-1-[(2-phenylcyclopropyl)methyl]-4-(2, 4-dichlorophenyl)piperazine (5m) and (1S, 2S)-trans-1-[(2-phenylcyclopropyl)methyl]-4-(2, 4-dimethylphenyl)piperazine (5t) were selected for functional antagonists at D(2) and D(4) receptors and had a D(2)/D(4) ratio approximating that of clozapine; they proved inactive in behavioral tests of antipsychotic activity.

Design, synthesis, and discovery of 3-piperazinyl-3,4-dihydro-2(1H)-quinolinone derivatives: a novel series of mixed dopamine D2/D4 receptor antagonists.

3-Piperazinyl-3,4-dihydro-2(1H)-quinolinone derivatives (delta-lactams) were designed, synthesized, and identified as a new series of mixed dopamine D2/D4 receptor antagonists. To further the structure-activity relationship (SAR) study, 3-piperazinylindolin-2-ones (gamma-lactams) and 3-piperazinyl-3H,4H,5H-benzo[f]azepin-2-ones (epsilon-lactams) were also prepared and examined.

NGB 2904 and NGB 2849: two highly selective dopamine D3 receptor antagonists.

N-(4-[4-¿2, 3-dichlorophenyl¿-1-piperazinyl]butyl)-3-fluorenylcarboxamide and N-(4-[4-¿2, 3-dichlorophenyl¿-1-piperazinyl]butyl)-2-biphenylenylcarboxamide were prepared in several steps from 2,3-dichloroaniline. These compounds were identified as highly selective dopamine D3 receptor antagonists.

Atypical antipsychotic-like effects of the dopamine D3 receptor agonist, (+)-PD 128,907.

Anti-schizophrenia agents with improved efficacy and side-effect profiles are required. A dopamine D3 receptor agonist, R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3- b]-1,4-oxazin-9-ol HCl ((+)-PD 128,907), displayed an atypical antipsychotic profile comparable to that of clozapine. (+)-PD 128,907 blocked stereotypy produced by dizocilpine (MK-801) at 12-fold lower doses than those affecting apomorphine-induced stereotypes in mice and did not produce catalepsy.

II. Localization and characterization of dopamine D4 binding sites in rat and human brain by use of the novel, D4 receptor-selective ligand [3H]NGD 94-1.

The dopamine D4 selective ligand, [H]NGD 94-1, was used in these studies to characterize binding sites in rat and human brain tissue by membrane binding and autoradiography techniques. Autoradiographic analysis of rat brain showed that specific [3H]NGD 94-1 binding was greatest in entorhinal cortex, lateral septal nucleus, hippocampus and the medial preoptic area of the hypothalamus. This nonstriatal distribution of [3H]NGD 94-1 binding was distinct from the autoradiographic distribution of dopamine D2 and D3 receptor subtypes.

I. NGD 94-1: identification of a novel, high-affinity antagonist at the human dopamine D4 receptor.

NGD 94-1 was evaluated for selectivity and in vitro functional activity at the recombinant human D4.2 receptor stably expressed in Chinese hamster ovary cells. NGD 94-1 showed high affinity for the cloned human D4.

1-Phenyl-3-(aminomethyl)pyrroles as potential antipsychotic agents. Synthesis and dopamine receptor binding.

A series of 1-phenyl-3-(aminomethyl)pyrroles were prepared in two steps from aniline and their affinities for D2, D3, and D4 dopamine receptor subtypes determined. A 15-fold selectivity for cloned human D4 receptors over cloned African Green monkey D2 receptors was observed with 1-(2-pyridyl)-4-[[3-(1-phenylpyrrolyl)]methyl]piperazine.

2-Phenyl-4-(aminomethyl)imidazoles as potential antipsychotic agents. Synthesis and dopamine D2 receptor binding.

A series of 2-phenyl-4-(aminomethyl)imidazoles were designed as conformationally restricted analogs of the dopamine D2 selective benzamide antipsychotics. The title compounds were synthesized and tested for blockade of [3H]YM-09151 binding in cloned African green monkey dopamine D2 receptor preparations. The binding affinity data thus obtained were compared against that of the benzamides and a previously described series of 2-phenyl-5-(aminomethyl)-pyrroles.

An electrophilic affinity ligand based on (+)-MK801 distinguishes PCP site 1 from PCP site 2.

The electrophilic affinity ligand, (+)-3-isothiocyanato-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cycl ohepten-5,10 - imine hydrochloride [(+)-MK801-NCS] was characterized for its ability to acrylate phencyclidine (PCP) and sigma binding sites in vivo. Initial studies, conducted with mouse brain membranes, characterized the binding sites labeled by [3H]1-[1-(2-thienyl)cyclohexyl]piperidine ([3H]TCP). The Kd values of [3H]TCP for PCP site 1 (MK801-sensitive) and PCP site 2 (MK801-insensitive) were 12 nM and 68 nM, with Bmax values of 1442 and 734 fmol/mg protein, respectively.

Evaluation of ADCI against convulsant and locomotor stimulant effects of cocaine: comparison with the structural analogs dizocilpine and carbamazepine.

Both the antiepileptic, carbamazepine, and the N-methyl-D-aspartate receptor antagonist, dizocilpine, have shown preclinical efficacy against behavioral and toxic effects of cocaine. Nonetheless, side effects or toxicity of these compounds either alone or in conjunction with cocaine are problematic. 5-Aminocarbonyl-10,11-dihydro-5h-dibenzo[a,d]cyclohepten-5,1 0-imine (ADCI), a molecular hybrid of these compounds, has been shown to have a broad anticonvulsant profile with a good protective index (behavioral TD50/anticonvulsant ED50).

Fourphit: a selective probe for the methylphenidate binding site on the dopamine transporter.

Fourphit, a phencyclidine derivative containing an isothiocyanate substitution at the 4-position of the piperidine ring, inhibits the binding of the radiolabeled psychomotor stimulant, [3H]methylphenidate, to sites on the dopamine transport complex in membranes prepared from the crude synaptosomal fraction of rat striatal tissue with an IC50 of 7.1 microM. The inhibition caused by Fourphit is irreversible and is associated with a decrease in the Bmax, but not the KD, of [3H]methylphenidate binding.

Analogues of the dioxolanes dexoxadrol and etoxadrol as potential phencyclidine-like agents. Synthesis and structure-activity relationships.

A series of dioxolane analogues based on dexoxadrol ((4S,6S)-2,2-diphenyl-4-(2-piperidyl)-1,3-dioxolane) and etoxadrol ((2S,4S,6S)-2-ethyl-2-phenyl-4-(2-piperidyl)-1,3-dioxolane) were prepared and tested for their ability to displace [3H]TCP (1-[1-(2-thienyl)cyclohexyl]piperidine) from PCP (1-(1-phenylcyclohexyl)piperidine) binding sites in rat brain tissue homogenates. Qualitative structure-activity relationships within this series were explored through modifications of the three major structural units of dexoxadrol, the piperidine, 1,3-dioxolane, and aromatic rings of the molecule. N-Alkyl derivatives of dexoxadrol were found to be inactive, as were those analogues where the dioxolane ring was modified.

Comparison of the effects of the uncompetitive N-methyl-D-aspartate antagonist (+-)-5-aminocarbonyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-imine (ADCI) with its structural analogs dizocilpine (MK-801) and carbamazepine on ethanol withdrawal seizures.

The ability of [(+-)-5-aminocarbonyl-10,11-dihydro-5H-di-benzo [a,d]cyclohepten-5,10-imine (ADCI) and its structural analogs dizocilipine (MK-801) and carbamazepine to block ethanol withdrawal seizures was tested in mice made physically dependent upon ethanol. Three injections of either ADCI (ranging from 1.0-10.

Anticonvulsant 1-phenylcycloalkylamines: two analogues with low motor toxicity when orally administered.

1-Phenylcyclohexylamine (PCA) and its analogues 1-phenylcyclopentylamine (PPA) and 1-(3-fluorophenyl)cyclohexylamine (3-F-PCA) are potent anticonvulsants in the mouse maximal electroshock (MES) seizure test. Unlike the structurally related dissociative anesthetic phencyclidine (PCP), however, which produces motor toxicity at anticonvulsant doses, PCA, PPA, and 3-F-PCA protect against MES seizures at 2.2- to 3.

Anticonvulsant activity of the low-affinity uncompetitive N-methyl-D- aspartate antagonist (+-)-5-aminocarbonyl-10,11-dihydro-5H- dibenzo[a,d]cyclohepten-5,10-imine (ADCI): comparison with the structural analogs dizocilpine (MK-801) and carbamazepine.

(+-)-5-Aminocarbonyl-10,11-dihydro-5H-dibenzo[a,d] [a,d]cyclohepten-5,10-imine (ADCI), a tricyclic compound structurally related to dizocilpine (MK-801) and carbamazepine, was a potent anticonvulsant in the mouse maximal electroshock seizure test when administered i.p. (ED50, 8.

GBR12909 antagonizes the ability of cocaine to elevate extracellular levels of dopamine.

Rats were administered various IP doses of the high-affinity dopamine (DA) reuptake inhibitor 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-[3-phenylpropyl]piperazine (GBR12909). The caudate nuclei were removed 60 min after drug administration and stored at -70 degrees C. Striatal membranes were prepared later.

[3H]1-[2-(2-thienyl)cyclohexyl]piperidine labels two high-affinity binding sites in human cortex: further evidence for phencyclidine binding sites associated with the biogenic amine reuptake complex.

Previous work demonstrated two high-affinity PCP binding sites in guinea pig brain labeled by [3H]TCP (1-(1-[2-thienyl]cyclohexyl)piperidine): site 1 (N-methyl-D-aspartate [NMDA]-associated) and site 2 (dopamine-reuptake complex associated). The present study examined brain membranes prepared from various species, including human, for the presence of site 2, defined as binding in the presence of (+)-5-methyl-10,11-dihydro-5H-dibenzo [a, d]cyclohepten-5,10-imine maleate ((+)-MK801) minus binding in the presence of 10 microM TCP (nonspecific binding). Studies were conducted in absence of sodium which was found to be inhibitory to [3H]TCP binding.