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1.
J Pharmacol Exp Ther ; 371(2): 526-543, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31413138

RESUMEN

Despite escalating methamphetamine use and high relapse rates, pharmacotherapeutics for methamphetamine use disorders are not available. Our iterative drug discovery program had found that R-N-(1,2-dihydroxypropyl)-2,6-cis-di-(4-methoxyphenethyl)piperidine hydrochloride (GZ-793A), a selective vesicular monoamine transporter-2 (VMAT2) inhibitor, specifically decreased methamphetamine's behavioral effects. However, GZ-793A inhibited human-ether-a-go-go-related gene (hERG) channels, suggesting cardiotoxicity and prohibiting clinical development. The current study determined if replacement of GZ-793A's piperidine ring with a phenylalkyl group to yield S-3-(4-methoxyphenyl)-N-(1-phenylpropan-2-yl)propan-1-amine (GZ-11608) diminished hERG interaction while retaining pharmacological efficacy. VMAT2 inhibition, target selectivity, and mechanism of GZ-11608-induced inhibition of methamphetamine-evoked vesicular dopamine release were determined. We used GZ-11608 doses that decreased methamphetamine-sensitized activity to evaluate the potential exacerbation of methamphetamine-induced dopaminergic neurotoxicity. GZ-11608-induced decreases in methamphetamine reinforcement and abuse liability were determined using self-administration, reinstatement, and substitution assays. Results show that GZ-11608 exhibited high affinity (Ki = 25 nM) and selectivity (92-1180-fold) for VMAT2 over nicotinic receptors, dopamine transporter, and hERG, suggesting low side-effects. GZ-11608 (EC50 = 620 nM) released vesicular dopamine 25-fold less potently than it inhibited VMAT2 dopamine uptake. GZ-11608 competitively inhibited methamphetamine-evoked vesicular dopamine release (Schild regression slope = 0.9 ± 0.13). GZ-11608 decreased methamphetamine sensitization without altering striatal dopamine content or exacerbating methamphetamine-induced dopamine depletion, revealing efficacy without neurotoxicity. GZ-11608 exhibited linear pharmacokinetics and rapid brain penetration. GZ-11608 decreased methamphetamine self-administration, and this effect was not surmounted by increasing methamphetamine unit doses. GZ-11608 reduced cue- and methamphetamine-induced reinstatement, suggesting potential to prevent relapse. GZ-11608 neither served as a reinforcer nor substituted for methamphetamine, suggesting low abuse liability. Thus, GZ-11608, a potent and selective VMAT2 inhibitor, shows promise as a therapeutic for methamphetamine use disorder. SIGNIFICANCE STATEMENT: GZ-11608 is a potent and selective vesicular monoamine transporter-2 inhibitor that decreases methamphetamine-induced dopamine release from isolated synaptic vesicles from brain dopaminergic neurons. Results from behavioral studies show that GZ-11608 specifically decreases methamphetamine-sensitized locomotor activity, methamphetamine self-administration, and reinstatement of methamphetamine-seeking behavior, without exhibiting abuse liability. Tolerance does not develop to the efficacy of GZ-11608 to decrease the behavioral effects of methamphetamine. In conclusion, GZ-11608 is an outstanding lead in our search for a therapeutic to treat methamphetamine use disorder.


Asunto(s)
Conducta Adictiva/tratamiento farmacológico , Encéfalo/efectos de los fármacos , Inhibidores de Captación de Dopamina/administración & dosificación , Locomoción/efectos de los fármacos , Metanfetamina/administración & dosificación , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Animales , Conducta Adictiva/metabolismo , Conducta Adictiva/psicología , Encéfalo/metabolismo , Dopamina/metabolismo , Relación Dosis-Respuesta a Droga , Locomoción/fisiología , Masculino , Ratas , Ratas Sprague-Dawley , Autoadministración , Sinaptosomas/efectos de los fármacos , Sinaptosomas/metabolismo , Proteínas de Transporte Vesicular de Monoaminas/metabolismo
2.
Bioorg Med Chem Lett ; 27(24): 5467-5472, 2017 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-29153425

RESUMEN

A small library of fluoroethoxy-1,4-diphenethyl piperidine and fluoroethoxy-1,4-diphenethyl piperazine derivatives were designed, synthesized and evaluated for their ability to inhibit [3H]dopamine (DA) uptake at the vesicular monoamine transporter-2 (VMAT2) and dopamine transporter (DAT), [3H]serotonin (5-HT) uptake at the serotonin transporter (SERT), and [3H]dofetilide binding at the human-ether-a-go-go-related gene (hERG) channel. The majority of the compounds exhibited potent inhibition of [3H]DA uptake at VMAT2, Ki changes in the nanomolar range (Ki = 0.014-0.073 µM). Compound 15d exhibited the highest affinity (Ki = 0.014 µM) at VMAT2, and had 160-, 5-, and 60-fold greater selectivity for VMAT2 vs. DAT, SERT and hERG, respectively. Compound 15b exhibited the greatest selectivity (>60-fold) for VMAT2 relative to all the other targets evaluated, and 15b had high affinity for VMAT2 (Ki = 0.073 µM). Compound 15b was considered the lead compound from this analog series due to its high affinity and selectivity for VMAT2.


Asunto(s)
Dopamina/metabolismo , Piperazinas/química , Piperidinas/química , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/química , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Canal de Potasio ERG1/metabolismo , Humanos , Cinética , Piperazinas/metabolismo , Piperidinas/metabolismo , Unión Proteica , Serotonina/metabolismo , Proteínas de Transporte de Serotonina en la Membrana Plasmática/química , Proteínas de Transporte de Serotonina en la Membrana Plasmática/metabolismo , Relación Estructura-Actividad , Proteínas de Transporte Vesicular de Monoaminas/metabolismo
3.
Bioorg Med Chem ; 25(1): 58-66, 2017 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-27769670

RESUMEN

The emergence of multidrug-resistant bacterial and fungal strains poses a threat to human health that requires the design and synthesis of new classes of antimicrobial agents. We evaluated bis(N-amidinohydrazones) and N-(amidino)-N'-aryl-bishydrazones for their antibacterial and antifungal activities against panels of Gram-positive/Gram-negative bacteria as well as fungi. We investigated their potential to develop resistance against both bacteria and fungi by a multi-step resistance-selection method, explored their potential to induce the production of reactive oxygen species, and assessed their toxicity. In summary, we found that these compounds exhibited broad-spectrum antibacterial and antifungal activities against most of the tested strains with minimum inhibitory concentration (MIC) values ranging from <0.5 to >500µM against bacteria and 1.0 to >31.3µg/mL against fungi; and in most cases, they exhibited either superior or similar antimicrobial activity compared to those of the standard drugs used in the clinic. We also observed minimal emergence of drug resistance to these newly synthesized compounds by bacteria and fungi even after 15 passages, and we found weak to moderate inhibition of the human Ether-à-go-go-related gene (hERG) channel with acceptable IC50 values ranging from 1.12 to 3.29µM. Overall, these studies show that bis(N-amidinohydrazones) and N-(amidino)-N'-aryl-bishydrazones are potentially promising scaffolds for the discovery of novel antibacterial and antifungal agents.


Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Hidrazonas/química , Hidrazonas/farmacología , Bacterias/efectos de los fármacos , Infecciones Bacterianas/tratamiento farmacológico , Candida albicans/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Línea Celular , Descubrimiento de Drogas , Resistencia a Múltiples Medicamentos , Hongos/efectos de los fármacos , Humanos , Pruebas de Sensibilidad Microbiana , Micosis/tratamiento farmacológico
4.
Bioorg Med Chem Lett ; 26(10): 2422-2427, 2016 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-27080180

RESUMEN

A series of lobelane and GZ-793A analogues that incorporate aromatic 4-hydroxy and 4-(2-fluoroethoxy) substituents were synthesized and evaluated for inhibition of [(3)H]dopamine (DA) uptake at the vesicular monoamine transporter-2 (VMAT2) and the dopamine transporter (DAT), and [(3)H]serotonin uptake at the serotonin transporter (SERT). Most of these compounds exhibited potent inhibition of DA uptake at VMAT2 in the nanomolar range (Ki=30-70nM). The two most potent analogues, 7 and 14, both exhibited a Ki value of 31nM for inhibition of VMAT2. The lobelane analogue 14, incorporating 4-(2-fluoroethoxy) and 4-hydroxy aromatic substituents, exhibited 96- and 335-fold greater selectivity for VMAT2 versus DAT and SERT, respectively, in comparison to lobelane. Thus, lobelane analogues bearing hydroxyl and fluoroethoxy moieties retain the high affinity for VMAT2 of the parent compound, while enhancing selectivity for VMAT2 versus the plasmalemma transporters.


Asunto(s)
Inhibidores de Captación de Dopamina/química , Inhibidores de Captación de Dopamina/farmacología , Lobelina/análogos & derivados , Proteínas de Transporte Vesicular de Monoaminas/metabolismo , Técnicas de Química Sintética , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/antagonistas & inhibidores , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Evaluación Preclínica de Medicamentos/métodos , Lobelina/síntesis química , Lobelina/química , Lobelina/farmacología , Proteínas de Transporte de Serotonina en la Membrana Plasmática/metabolismo , Inhibidores Selectivos de la Recaptación de Serotonina/química , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Relación Estructura-Actividad , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores
5.
Bioorg Med Chem Lett ; 26(13): 2997-3000, 2016 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-27212067

RESUMEN

A series of 1,4-diphenalkylpiperidine analogs were synthesized and evaluated for their affinity and inhibitory potency at the [(3)H]dihydrotetrabenazine (DTBZ) binding site and [(3)H]dopamine (DA) uptake site on the vesicular monoamine transporter-2 (VMAT2). Results revealed that translocation of the phenethyl side chains of lobelane from C2 and C6 to C1 and C4 around the central piperidine ring slightly reduces affinity and inhibitory potency at VMAT2 with respect to lobelane. However, methoxy and fluoro-substitution of either phenyl ring of these 1,4-diphenethyl analogs afforded VMAT2 inhibition comparable or higher (5-fold) affinity at the DTBZ binding and DA uptake sites relative to lobelane, whereas replacement of the 4-phenethyl moiety in these analogs with a 4-phenmethyl moiety markedly reduced affinity for the DTBZ binding and DA uptake sites by 3- and 5-fold, respectively. Among the twenty five 1,4-diphenethylpiperidine analogs evaluated, compounds containing a 4-(2-methoxyphenethyl) moiety exhibited the most potent inhibition of DTBZ binding and vesicular DA uptake. From this subgroup, analogs 8h, 8j and 8m exhibited Ki values of 9.3nM, 13nM and 13nM, respectively, for inhibition of [(3)H]DA uptake by VMAT2, and represent some of the most potent inhibitors of VMAT2 function reported thus far.


Asunto(s)
Piperidinas/farmacología , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Animales , Sitios de Unión , Encéfalo/metabolismo , Diseño de Fármacos , Lobelina/análogos & derivados , Lobelina/farmacología , Piperidinas/síntesis química , Piperidinas/química , Ensayo de Unión Radioligante , Ratas , Relación Estructura-Actividad
6.
Bioorg Med Chem Lett ; 26(18): 4441-4445, 2016 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-27524311

RESUMEN

A small library of 1,4-diphenethylpiperazine analogs was synthesized and evaluated for inhibition of [(3)H]dihydrotetrabenazine binding and [(3)H]dopamine uptake at the vesicular monoamine transporter-2 (VMAT2). Results from these studies identified three novel molecules, 6b, 6e and 9a (Ki=35nM, 48nM and 37nM, respectively) that exhibit similar potency for inhibition of VMAT2 function compared with lobelane (Ki=45nM), and importantly, have enhanced water-solubility when compared to the previously reported 1,4-diphenethylpiperidine analogs. These 1,4-diphenethylpiperazine analogs constitute promising new leads in the discovery of potential pharmacotherapeutics for treatment of methamphetamine use disorders.


Asunto(s)
Piperazinas/síntesis química , Piperazinas/farmacología , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Técnicas In Vitro
7.
Org Biomol Chem ; 14(1): 74-84, 2016 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-26548370

RESUMEN

Advanced prostate tumors usually metastasize to the lung, bone, and other vital tissues and are resistant to conventional therapy. Prostate apoptosis response-4 protein (Par-4) is a tumor suppressor that causes apoptosis in therapy-resistant prostate cancer cells by binding specifically to a receptor, Glucose-regulated protein-78 (GRP78), found only on the surface of cancer cells. 3-Arylquinolines or "arylquins" induce normal cells to release Par-4 from the intermediate filament protein, vimentin and promote Par-4 secretion that targets cancer cells in a paracrine manner. A structure-activity study identified arylquins that promote Par-4 secretion, and an evaluation of arylquin binding to the hERG potassium ion channel using a [(3)H]-dofetilide binding assay permitted the identification of structural features that separated this undesired activity from the desired Par-4 secretory activity. A binding study that relied on the natural fluorescence of arylquins and that used the purified rod domain of vimentin (residues 99-411) suggested that the mechanism behind Par-4 release involved arylquin binding to multiple sites in the rod domain.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Quinolonas/metabolismo , Quinolonas/farmacología , Vimentina/metabolismo , Sitios de Unión/efectos de los fármacos , Chaperón BiP del Retículo Endoplásmico , Canales de Potasio Éter-A-Go-Go/metabolismo , Humanos , Estructura Molecular , Quinolonas/química , Estereoisomerismo , Relación Estructura-Actividad , Vimentina/química
8.
Bioorg Med Chem Lett ; 25(13): 2613-6, 2015 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-25991431

RESUMEN

We have previously shown that quinolyl moieties are attractive structural replacements for the phenyl groups in lobelane. These quinolyl analogues had improved water-solubility over lobelane and retained the potent vesicular monoamine transporter-2 (VMAT-2) inhibitory properties of the parent compound, with quinlobelane (4) exhibiting potent inhibition of uptake at VMAT-2 (Ki=51nM). However, the VMAT-2 inhibitory properties of quinolyl analogues of norlobelane, which is equipotent with lobeline as an inhibitor of [(3)H]dopamine (DA) uptake at VMAT-2, have not been reported. In the current communication, we describe the synthesis of some novel des-methyl quinolyl analogues of lobelane that exhibit greater affinity (Ki=178-647nM) for the dihydrotetrabenazine binding site located on VMAT-2 compared with lobelane (Ki=970nM), norlobelane (Ki=2310nM) and quinlobelane (Ki=2640nM). The most potent compounds, 14 and 15, also exhibited inhibition of [(3)H]DA uptake at VMAT-2 (Ki=42nM) which was comparable to both lobelane (Ki=45nM) and norlobelane (Ki=43nM). Results reveal that binding affinity at VMAT-2 serves as an accurate predictor of inhibition of the function of VMAT-2 for the majority of these analogues. These novel analogues are under consideration for further development as treatments for methamphetamine abuse.


Asunto(s)
Dopamina/metabolismo , Lobelina/análogos & derivados , Tetrabenazina/análogos & derivados , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Trastornos Relacionados con Anfetaminas/tratamiento farmacológico , Trastornos Relacionados con Anfetaminas/metabolismo , Animales , Sitios de Unión , Humanos , Técnicas In Vitro , Cinética , Lobelina/química , Lobelina/farmacología , Metanfetamina/metabolismo , Ratas , Relación Estructura-Actividad , Vesículas Sinápticas/efectos de los fármacos , Vesículas Sinápticas/metabolismo , Tetrabenazina/metabolismo , Proteínas de Transporte Vesicular de Monoaminas/metabolismo
9.
Biochem Pharmacol ; : 116189, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38580165

RESUMEN

Previous research has demonstrated therapeutic potential for VMAT2 inhibitors in rat models of methamphetamine use disorder. Here, we report on the neurochemical and behavioral effects of 1-(2-methoxyphenethyl)-4-phenethypiperazine (JPC-141), a novel analog of lobelane. JPC-141 potently inhibited (Ki = 52 nM) [3H]dopamine uptake by VMAT2 in striatal vesicles with 50 to 250-fold greater selectivity for VMAT2 over dopamine, norepinephrine and serotonin plasmalemma transporters. Also, JPC-141 was 57-fold more selective for inhibiting VMAT2 over [3H]dofetilide binding to hERG channels expressed by HEK293, suggesting relatively low potential for cardiotoxicity. When administered in vivo to rats, JPC-141 prevented the METH-induced reduction in striatal dopamine content when given either prior to or after a high dose of METH, suggesting a reduction in METH-induced dopaminergic neurotoxicity. In behavioral assays, JPC-141 decreased METH-stimulated locomotor activity in METH-sensitized rats at doses of JPC-141 which did not alter locomotor activity in the saline control group. Moreover, JPC-141 specifically decreased iv METH self-administration at doses that had no effect on food-maintained responding. These findings support the further development of VMAT2 inhibitors as pharmacotherapies for individuals with methamphetamine use disorder.

10.
J Neurochem ; 127(2): 177-86, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23875622

RESUMEN

(R)-3-[2,6-cis-Di(4-methoxyphenethyl)piperidin-1-yl]propane-1,2-diol (GZ-793A) inhibits methamphetamine-evoked dopamine release from striatal slices and methamphetamine self-administration in rats. GZ-793A potently and selectively inhibits dopamine uptake at the vesicular monoamine transporter-2 (VMAT2). This study determined GZ-793A's ability to evoke [³H]dopamine release and inhibit methamphetamine-evoked [³H]dopamine release from isolated striatal synaptic vesicles. Results show GZ-793A concentration-dependent [³H]dopamine release; nonlinear regression revealed a two-site model of interaction with VMAT2 (High- and Low-EC50 = 15.5 nM and 29.3 µM, respectively). Tetrabenazine and reserpine completely inhibited GZ-793A-evoked [³H]dopamine release, however, only at the High-affinity site. Low concentrations of GZ-793A that interact with the extravesicular dopamine uptake site and the High-affinity intravesicular DA release site also inhibited methamphetamine-evoked [³H]dopamine release from synaptic vesicles. A rightward shift in the methamphetamine concentration-response was evident with increasing concentrations of GZ-793A, and the Schild regression slope was 0.49 ± 0.08, consistent with surmountable allosteric inhibition. These results support a hypothetical model of GZ-793A interaction at more than one site on the VMAT2 protein, which explains its potent inhibition of dopamine uptake, dopamine release via a High-affinity tetrabenazine- and reserpine-sensitive site, dopamine release via a Low-affinity tetrabenazine- and reserpine-insensitive site, and a low-affinity interaction with the dihydrotetrabenazine binding site on VMAT2. GZ-793A inhibition of the effects of methamphetamine supports its potential as a therapeutic agent for the treatment of methamphetamine abuse.


Asunto(s)
Inhibidores de Captación de Dopamina/antagonistas & inhibidores , Lobelina/análogos & derivados , Metanfetamina/antagonistas & inhibidores , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Proteínas de Transporte Vesicular de Monoaminas/metabolismo , Inhibidores de Captación Adrenérgica/farmacología , Animales , Interpretación Estadística de Datos , Dopamina/metabolismo , Inhibidores de Captación de Dopamina/farmacología , Lobelina/farmacología , Masculino , Metanfetamina/farmacología , Neostriado/efectos de los fármacos , Neostriado/metabolismo , Ratas , Ratas Sprague-Dawley , Reserpina/farmacología , Vesículas Sinápticas/efectos de los fármacos , Vesículas Sinápticas/metabolismo , Tetrabenazina/farmacología
11.
Bioorg Med Chem Lett ; 23(11): 3342-5, 2013 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-23597792

RESUMEN

Central heterocyclic ring size reduction from piperidinyl to pyrrolidinyl in the vesicular monoamine transporter-2 (VMAT2) inhibitor GZ-793A and its analogs resulted in novel N-propane-1,2(R)-diol analogs 11a-i. These compounds were evaluated for their affinity for the dihydrotetrabenazine (DTBZ) binding site on VMAT2 and for their ability to inhibit vesicular dopamine (DA) uptake. The 4-difluoromethoxyphenethyl analog 11f was the most potent inhibitor of [(3)H]-DTBZ binding (Ki=560 nM), with 15-fold greater affinity for this site than GZ-793A (Ki=8.29 µM). Analog 11f also showed similar potency of inhibition of [(3)H]-DA uptake into vesicles (Ki=45 nM) compared to that for GZ-793A (Ki=29 nM). Thus, 11f represents a new water-soluble inhibitor of VMAT function.


Asunto(s)
Lobelina/análogos & derivados , Pirrolidinas/química , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Animales , Sitios de Unión , Dopamina/metabolismo , Lobelina/síntesis química , Lobelina/química , Lobelina/metabolismo , Unión Proteica , Pirrolidinas/síntesis química , Pirrolidinas/metabolismo , Ratas , Vesículas Sinápticas/metabolismo , Tetrabenazina/análogos & derivados , Tetrabenazina/química , Tetrabenazina/metabolismo , Proteínas de Transporte Vesicular de Monoaminas/metabolismo
12.
Bioorg Med Chem ; 21(21): 6771-7, 2013 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-23993667

RESUMEN

Lobelane analogs that incorporate a central piperidine or pyrrolidine moiety have previously been reported by our group as potent inhibitors of VMAT2 function. Further central ring size reduction of the piperidine moiety in lobelane to a four-membered heterocyclic ring has been carried out in the current study to afford novel cis-and trans-azetidine analogs. These azetidine analogs (15a-15c and 22a-22c) potently inhibited [(3)H]dopamine (DA) uptake into isolated synaptic vesicles (Ki⩽66nM). The cis-4-methoxy analog 22b was the most potent inhibitor (Ki=24nM), and was twofold more potent that either lobelane (2a, Ki=45nM) or norlobelane (2b, Ki=43nM). The trans-methylenedioxy analog, 15c (Ki=31nM), was equipotent with the cis-analog, 22b, in this assay. Thus, cis- and trans-azetidine analogs 22b and 15c represent potential leads in the discovery of new clinical candidates for the treatment of methamphetamine abuse.


Asunto(s)
Azetidinas/química , Inhibidores de Captación de Dopamina/síntesis química , Dopamina/metabolismo , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Animales , Azetidinas/síntesis química , Azetidinas/metabolismo , Inhibidores de Captación de Dopamina/química , Inhibidores de Captación de Dopamina/metabolismo , Isomerismo , Cinética , Lobelina/análogos & derivados , Lobelina/química , Lobelina/metabolismo , Unión Proteica , Ratas , Vesículas Sinápticas/metabolismo , Tritio/química , Proteínas de Transporte Vesicular de Monoaminas/metabolismo
13.
J Pharmacol Exp Ther ; 336(3): 724-33, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20876747

RESUMEN

Lobeline attenuates the behavioral effects of methamphetamine via inhibition of the vesicular monoamine transporter (VMAT2). To increase selectivity for VMAT2, chemically defunctionalized lobeline analogs, including lobelane, were designed to eliminate nicotinic acetylcholine receptor affinity. The current study evaluated the ability of lobelane analogs to inhibit [³H]dihydrotetrabenazine (DTBZ) binding to VMAT2 and [³H]dopamine (DA) uptake into isolated synaptic vesicles and determined the mechanism of inhibition. Introduction of aromatic substituents in lobelane maintained analog affinity for the [³H]DTBZ binding site on VMAT2 and inhibitory potency in the [³H]DA uptake assay assessing VMAT2 function. The most potent (K(i) = 13-16 nM) analogs in the series included para-methoxyphenyl nor-lobelane (GZ-252B), para-methoxyphenyl lobelane (GZ-252C), and 2,4-dichlorphenyl lobelane (GZ-260C). Affinity of the analogs for the [³H]DTBZ binding site did not correlate with inhibitory potency in the [³H]DA uptake assay. It is noteworthy that the N-benzylindole-, biphenyl-, and indole-bearing meso-analogs 2,6-bis[2-(1-benzyl-1H-indole-3-yl)ethyl]-1-methylpiperidine hemifumarate (AV-1-292C), 2,6-bis(2-(biphenyl-4-yl)ethyl)piperidine hydrochloride (GZ-272B), and 2,6-bis[2-(1H-indole-3-yl)ethyl]-1-methylpiperidine monofumarate (AV-1-294), respectively] inhibited VMAT2 function (K(i) = 73, 127, and 2130 nM, respectively), yet had little to no affinity for the [³H]DTBZ binding site. These results suggest that the analogs interact at an alternate site to DTBZ on VMAT2. Kinetic analyses of [³H]DA uptake revealed a competitive mechanism for 2,6-bis(2-(4-methoxyphenyl)ethyl)piperidine hydrochloride (GZ-252B), 2,6-bis(2-(4-methoxyphenyl)ethyl)-1-methylpiperidine hydrochloride (GZ-252C), 2,6-bis(2-(2,4-dichlorophenyl)ethyl)piperidine hydrochloride (GZ-260C), and GZ-272B. Similar to methamphetamine, these analogs released [³H]DA from the vesicles, but with higher potency. In contrast to methamphetamine, these analogs had higher potency (>100-fold) at VMAT2 than DAT, predicting low abuse liability. Thus, modification of the lobelane molecule affords potent, selective inhibitors of VMAT2 function and reveals two distinct pharmacological targets on VMAT2.


Asunto(s)
Dopamina/metabolismo , Lobelina/análogos & derivados , Tritio/metabolismo , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Proteínas de Transporte Vesicular de Monoaminas/metabolismo , Animales , Relación Dosis-Respuesta a Droga , Lobelina/química , Lobelina/metabolismo , Masculino , Unión Proteica/fisiología , Transporte de Proteínas/fisiología , Ratas , Ratas Sprague-Dawley
14.
J Pharmacol Exp Ther ; 332(2): 612-21, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19855096

RESUMEN

Lobeline is currently being evaluated in clinical trials as a methamphetamine abuse treatment. Lobeline interacts with nicotinic receptor subtypes, dopamine transporters (DATs), and vesicular monoamine transporters (VMAT2s). Methamphetamine inhibits VMAT2 and promotes dopamine (DA) release from synaptic vesicles, resulting ultimately in increased extracellular DA. The present study generated structure-activity relationships by defunctionalizing the lobeline molecule and determining effects on [(3)H]dihydrotetrabenazine binding, inhibition of [(3)H]DA uptake into striatal synaptic vesicles and synaptosomes, the mechanism of VMAT2 inhibition, and inhibition of methamphetamine-evoked DA release. Compared with lobeline, the analogs exhibited greater potency inhibiting DA transporter (DAT) function. Saturated analogs, lobelane and nor-lobelane, exhibited high potency (K(i) = 45 nM) inhibiting vesicular [(3)H]DA uptake, and lobelane competitively inhibited VMAT2 function. Lobeline and lobelane exhibited 67- and 35-fold greater potency, respectively, in inhibiting VMAT2 function compared to DAT function. Lobelane potently decreased (IC(50) = 0.65 microM; I(max) = 73%) methamphetamine-evoked DA overflow, and with a greater maximal effect compared with lobeline (IC(50) = 0.42 microM, I(max) = 56.1%). These results provide support for VMAT2 as a target for inhibition of methamphetamine effects. Both trans-isomers and demethylated analogs of lobelane had reduced or unaltered potency inhibiting VMAT2 function and lower maximal inhibition of methamphetamine-evoked DA release compared with lobelane. Thus, defunctionalization, cis-stereochemistry of the side chains, and presence of the piperidino N-methyl are structural features that afford greatest inhibition of methamphetamine-evoked DA release and enhancement of selectivity for VMAT2. The current results reveal that lobelane, a selective VMAT2 inhibitor, inhibits methamphetamine-evoked DA release and is a promising lead for the development of a pharmacotherapeutic for methamphetamine abuse.


Asunto(s)
Dopamina/metabolismo , Lobelina/análogos & derivados , Metanfetamina/farmacología , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Ácido 3,4-Dihidroxifenilacético/metabolismo , Trastornos Relacionados con Anfetaminas/tratamiento farmacológico , Animales , Cuerpo Estriado/efectos de los fármacos , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/antagonistas & inhibidores , Evaluación Preclínica de Medicamentos , Lobelina/farmacología , Lobelina/uso terapéutico , Masculino , Agonistas Nicotínicos/farmacología , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Vesículas Sinápticas/metabolismo , Sinaptosomas/metabolismo
15.
J Pharmacol Exp Ther ; 335(3): 841-51, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20805303

RESUMEN

Both lobeline and lobelane attenuate methamphetamine self-administration in rats by decreasing methamphetamine-induced dopamine release via interaction with vesicular monoamine transporter-2 (VMAT2). A novel derivative of nor-lobelane, cis-2,5-di-(2-phenethyl)-pyrrolidine hydrochloride (UKCP-110), and its trans-isomers, (2R,5R)-trans-di-(2-phenethyl)-pyrrolidine hydrochloride (UKCP-111) and (2S,5S)-trans-di-(2-phenethyl)-pyrrolidine hydrochloride (UKCP-112), were evaluated for inhibition of [(3)H]dihydrotetrabenazine binding and [(3)H]dopamine uptake by using a rat synaptic vesicle preparation to assess VMAT2 interaction. Compounds were evaluated for inhibition of [(3)H]nicotine and [(3)H]methyllycaconitine binding to assess interaction with the major nicotinic receptor subtypes. In addition, compounds were evaluated for inhibition of methamphetamine-evoked endogenous dopamine release by using striatal slices. The most promising compound, UKCP-110, was evaluated for its ability to decrease methamphetamine self-administration and methamphetamine discriminative stimulus cues and for its effect on food-maintained operant responding. UKCP-110, UKCP-111, and UKCP-112 inhibited [(3)H]dihydrotetrabenazine binding (K(i) = 2.66 ± 0.37, 1.05 ± 0.10, and 3.80 ± 0.31 µM, respectively) and had high potency inhibiting [(3)H]dopamine uptake (K(i) = 0.028 ± 0.001, 0.046 ± 0.008, 0.043 ± 0.004 µM, respectively), but lacked affinity at nicotinic receptors. Although the trans-isomers did not alter methamphetamine-evoked dopamine release, UKCP-110 inhibited (IC(50) = 1.8 ± 0.2 µM; I(max) = 67.18 ± 6.11 µM) methamphetamine-evoked dopamine release. At high concentrations, UKCP-110 also increased extracellular dihydroxyphenylacetic acid. It is noteworthy that UKCP-110 decreased the number of methamphetamine self-infusions, while having no effect on food-reinforced behavior or the methamphetamine stimulus cue. Thus, UKCP-110 represents a new lead in the development of novel pharmacotherapies for the treatment of methamphetamine abuse.


Asunto(s)
Trastornos Relacionados con Anfetaminas/tratamiento farmacológico , Dopamina/metabolismo , Lobelina/análogos & derivados , Lobelina/farmacología , Metanfetamina/farmacología , Pirrolidinas/farmacología , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Ácido 3,4-Dihidroxifenilacético/metabolismo , Aconitina/análogos & derivados , Aconitina/metabolismo , Animales , Conducta Animal/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Condicionamiento Operante , Cuerpo Estriado/citología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Tolerancia a Medicamentos , Lobelina/metabolismo , Masculino , Metanfetamina/administración & dosificación , Nicotina/metabolismo , Unión Proteica/efectos de los fármacos , Pirrolidinas/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores Nicotínicos/metabolismo , Refuerzo en Psicología , Autoadministración , Vesículas Sinápticas/efectos de los fármacos , Vesículas Sinápticas/metabolismo , Tetrabenazina/análogos & derivados , Tetrabenazina/metabolismo , Proteínas de Transporte Vesicular de Monoaminas/metabolismo
16.
Eur J Pharmacol ; 795: 143-149, 2017 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-27986625

RESUMEN

Lobeline and lobelane inhibit the behavioral and neurochemical effects of methamphetamine via an interaction with the vesicular monoamine transporter-2 (VMAT2). However, lobeline has high affinity for nicotinic receptors, and tolerance develops to the behavioral effects of lobelane. A water-soluble analog of lobelane, R-N-(1,2-dihydroxypropyl)-2,6-cis-di-(4-methoxyphenethyl)piperidine hydrochloride (GZ-793A), also interacts selectively with VMAT2 to inhibit the effects of methamphetamine, but does not produce behavioral tolerance. The current study further evaluated the mechanism underlying the GZ-793A-mediated inhibition of the neurochemical effects of methamphetamine. In contrast to lobeline, GZ-793A does not interact with the agonist recognition site on α4ß2* and α7* nicotinic receptors. GZ-793A (0.3-100µM) inhibited methamphetamine (5µM)-evoked fractional dopamine release from rat striatal slices, and did not evoke dopamine release in the absence of methamphetamine. Furthermore, GZ-793A (1-100µM) inhibited neither nicotine (30µM)-evoked nor electrical field-stimulation-evoked (100Hz/1min) fractional dopamine release. Unfortunately, GZ-793A inhibited [3H]dofetilide binding to human-ether-a-go-go related gene channels expressed on human embryonic kidney cells, and further, prolonged action potentials in rabbit cardiac Purkinje fibers, suggesting the potential for GZ-793A to induce ventricular arrhythmias. Thus, GZ-793A selectively inhibits the neurochemical effects of methamphetamine and lacks nicotinic receptor interactions; however, development as a pharmacotherapy for methamphetamine use disorders will not be pursued due to its potential cardiac liabilities.


Asunto(s)
Lobelina/análogos & derivados , Metanfetamina/farmacología , Proteínas de Transporte Vesicular de Monoaminas/metabolismo , Animales , Conducta Animal/efectos de los fármacos , Dopamina/metabolismo , Canal de Potasio ERG1/metabolismo , Estimulación Eléctrica , Células HEK293 , Humanos , Lobelina/metabolismo , Lobelina/farmacología , Masculino , Conejos , Ratas , Especificidad por Sustrato
17.
Neuropharmacology ; 109: 320-331, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27371135

RESUMEN

Stimulus-reward learning has been heavily linked to the reward-prediction error learning hypothesis and dopaminergic function. However, some evidence suggests dopaminergic function may not strictly underlie reward-prediction error learning, but may be specific to incentive salience attribution. Utilizing a Pavlovian conditioned approach procedure consisting of two stimuli that were equally reward-predictive (both undergoing reward-prediction error learning) but functionally distinct in regard to incentive salience (levers that elicited sign-tracking and tones that elicited goal-tracking), we tested the differential role of D1 and D2 dopamine receptors and nucleus accumbens dopamine in the acquisition of sign- and goal-tracking behavior and their associated conditioned reinforcing value within individuals. Overall, the results revealed that both D1 and D2 inhibition disrupted performance of sign- and goal-tracking. However, D1 inhibition specifically prevented the acquisition of sign-tracking to a lever, instead promoting goal-tracking and decreasing its conditioned reinforcing value, while neither D1 nor D2 signaling was required for goal-tracking in response to a tone. Likewise, nucleus accumbens dopaminergic lesions disrupted acquisition of sign-tracking to a lever, while leaving goal-tracking in response to a tone unaffected. Collectively, these results are the first evidence of an intraindividual dissociation of dopaminergic function in incentive salience attribution from reward-prediction error learning, indicating that incentive salience, reward-prediction error, and their associated dopaminergic signaling exist within individuals and are stimulus-specific. Thus, individual differences in incentive salience attribution may be reflective of a differential balance in dopaminergic function that may bias toward the attribution of incentive salience, relative to reward-prediction error learning only.


Asunto(s)
Condicionamiento Operante/fisiología , Dopamina/fisiología , Motivación/fisiología , Recompensa , Animales , Condicionamiento Operante/efectos de los fármacos , Antagonistas de los Receptores de Dopamina D2/farmacología , Relación Dosis-Respuesta a Droga , Masculino , Motivación/efectos de los fármacos , Núcleo Accumbens/efectos de los fármacos , Núcleo Accumbens/fisiología , Ratas , Ratas Sprague-Dawley , Receptores de Dopamina D1/antagonistas & inhibidores , Receptores de Dopamina D1/fisiología , Receptores de Dopamina D2/fisiología
18.
Adv Pharmacol ; 69: 71-106, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24484975

RESUMEN

Methamphetamine abuse escalates, but no approved therapeutics are available to treat addicted individuals. Methamphetamine increases extracellular dopamine in reward-relevant pathways by interacting at vesicular monoamine transporter-2 (VMAT2) to inhibit dopamine uptake and promote dopamine release from synaptic vesicles, increasing cytosolic dopamine available for reverse transport by the dopamine transporter (DAT). VMAT2 is the target of our iterative drug discovery efforts to identify pharmacotherapeutics for methamphetamine addiction. Lobeline, the major alkaloid in Lobelia inflata, potently inhibited VMAT2, methamphetamine-evoked striatal dopamine release, and methamphetamine self-administration in rats but exhibited high affinity for nicotinic acetylcholine receptors (nAChRs). Defunctionalized, unsaturated lobeline analog, meso-transdiene (MTD), exhibited lobeline-like in vitro pharmacology, lacked nAChR affinity, but exhibited high affinity for DAT, suggesting potential abuse liability. The 2,4-dicholorophenyl MTD analog, UKMH-106, exhibited selectivity for VMAT2 over DAT, inhibited methamphetamine-evoked dopamine release, but required a difficult synthetic approach. Lobelane, a saturated, defunctionalized lobeline analog, inhibited the neurochemical and behavioral effects of methamphetamine; tolerance developed to the lobelane-induced decrease in methamphetamine self-administration. Improved drug-likeness was afforded by the incorporation of a chiral N-1,2-dihydroxypropyl moiety into lobelane to afford GZ-793A, which inhibited the neurochemical and behavioral effects of methamphetamine, without tolerance. From a series of 2,5-disubstituted pyrrolidine analogs, AV-2-192 emerged as a lead, exhibiting high affinity for VMAT2 and inhibiting methamphetamine-evoked dopamine release. Current results support the hypothesis that potent, selective VMAT2 inhibitors provide the requisite preclinical behavioral profile for evaluation as pharmacotherapeutics for methamphetamine abuse and emphasize selectivity for VMAT2 relative to DAT as a criterion for reducing abuse liability of the therapeutic.


Asunto(s)
Trastornos Relacionados con Anfetaminas/tratamiento farmacológico , Sistemas de Liberación de Medicamentos/tendencias , Descubrimiento de Drogas/tendencias , Metanfetamina , Proteínas de Transporte Vesicular de Monoaminas/antagonistas & inhibidores , Trastornos Relacionados con Anfetaminas/metabolismo , Animales , Humanos , Lobelina/administración & dosificación , Lobelina/análogos & derivados , Lobelina/química , Lobelina/metabolismo , Metanfetamina/efectos adversos , Unión Proteica/efectos de los fármacos , Unión Proteica/fisiología , Resultado del Tratamiento , Proteínas de Transporte Vesicular de Monoaminas/metabolismo
19.
J Med Chem ; 57(14): 6083-91, 2014 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-24950374

RESUMEN

Inhibition of the catalytic subunit of the heterodimeric methionine S-adenosyl transferase-2 (MAT2A) with fluorinated N,N-dialkylaminostilbenes (FIDAS agents) offers a potential avenue for the treatment of liver and colorectal cancers where upregulation of this enzyme occurs. A study of structure-activity relationships led to the identification of the most active compounds as those with (1) either a 2,6-difluorostyryl or 2-chloro-6-fluorostyryl subunit, (2) either an N-methylamino or N,N-dimethylamino group attached in a para orientation relative to the 2,6-dihalostyryl subunit, and (3) either an N-methylaniline or a 2-(N,N-dimethylamino)pyridine ring. These modifications led to FIDAS agents that were active in the low nanomolar range, that formed water-soluble hydrochloride salts, and that possessed the desired property of not inhibiting the human hERG potassium ion channel at concentrations at which the FIDAS agents inhibit MAT2A. The active FIDAS agents may inhibit cancer cells through alterations of methylation reactions essential for cancer cell survival and growth.


Asunto(s)
Compuestos de Anilina/farmacología , Antineoplásicos/farmacología , Dominio Catalítico/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Metionina Adenosiltransferasa/antagonistas & inhibidores , Piridinas/farmacología , Pirimidinas/farmacología , Estilbenos/farmacología , Compuestos de Anilina/síntesis química , Compuestos de Anilina/química , Antineoplásicos/síntesis química , Antineoplásicos/química , Biocatálisis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Células HEK293 , Humanos , Metionina Adenosiltransferasa/metabolismo , Estructura Molecular , Subunidades de Proteína/efectos de los fármacos , Piridinas/síntesis química , Piridinas/química , Pirimidinas/síntesis química , Pirimidinas/química , Estilbenos/síntesis química , Estilbenos/química , Relación Estructura-Actividad , Células Tumorales Cultivadas
20.
Pharmacol Biochem Behav ; 108: 28-43, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23603417

RESUMEN

Mecamylamine (3-methylaminoisocamphane hydrochloride) is a nicotinic parasympathetic ganglionic blocker, originally utilized as a therapeutic agent to treat hypertension. Mecamylamine administration produces several deleterious side effects at therapeutically relevant doses. As such, mecamylamine's use as an antihypertensive agent was phased out, except in severe hypertension. Mecamylamine easily traverses the blood-brain barrier to reach the central nervous system (CNS), where it acts as a nicotinic acetylcholine receptor (nAChR) antagonist, inhibiting all known nAChR subtypes. Since nAChRs play a major role in numerous physiological and pathological processes, it is not surprising that mecamylamine has been evaluated for its potential therapeutic effects in a wide variety of CNS disorders, including addiction. Importantly, mecamylamine produces its therapeutic effects on the CNS at doses 3-fold lower than those used to treat hypertension, which diminishes the probability of peripheral side effects. This review focuses on the pharmacological properties of mecamylamine, the differential effects of its stereoisomers, S(+)- and R(-)-mecamylamine, and the potential for effectiveness in treating CNS disorders, including nicotine and alcohol addiction, mood disorders, cognitive impairment and attention deficit hyperactivity disorder.


Asunto(s)
Mecamilamina/uso terapéutico , Antagonistas Nicotínicos/uso terapéutico , Animales , Evaluación Preclínica de Medicamentos , Humanos , Mecamilamina/química , Antagonistas Nicotínicos/química , Estereoisomerismo
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