Chemistry And Pharmacology Of The Piperidine-based Analogues Of Cocaine. Identification Of Potent Dat Inhibitors Lacking The Tropane Skeleton
binding-sites; dopamine transporter; esters; Pharmacology & Pharmacy; substrate
To discover agents that might be useful in the treatment of cocaine abuse, we have chosen to re-explore a class of molecules that was first reported by Clarke et al. in 1973 and that was and shown to lack locomotor stimulatory activity in mice. These compounds are piperidine-3-carboxylic acid esters bearing a 4-chlorophenyl group in position 4, and as such, these structures may be viewed as truncated versions of the WIN series compounds, i.e., they lack the two-carbon bridge of the tropanes. All members of this class were synthesized starting from arecoline hydrobromide and obtained in optically pure form through resolution methods using either (+)- or (-)-dibenzoyltartaric acid. Interestingly, we have found that these piperidines do, in fact, exhibit substantial affinity in both WIN 35,428 binding at the dopamine transporter and in the inhibition of [H-3]dopamine uptake. Of all of the compounds synthesized, the 3-n-propyl derivative (-)-9 was found to be the most potent with a binding affinity of 3 nM. This simple piperidine is thus 33-fold more potent than cocaine in binding affinity and 29-fold more potent in its inhibition of dopamine uptake. Although no efforts have presently been made to "optimize" binding affinity at the DAT, the substantive activity found for the n-propyl derivative (-)-9 is remarkable; the compound is only about 10-fold less active than the best of the high-affinity tropanes of the WIN series. As a further point of interest, it was found that the cis-disubstituted piperidine (-)-3 is only about 2-fold more potent than its trans isomer (+)-11. This result stands in sharp contrast to the data reported for the tropane series, for the epimerization of the substituent at C-2 from beta to alpha has been reported to result in a lowering of activity by 30-200-fold. This smaller spread in binding affinities for the piperidines may reflect the smaller size of these molecules relative to the tropanes, which allows both the cis and the trans isomers to adjust themselves to the binding site on the DAT. Our present demonstration that these piperidine structures do, in fact, possess significant DAT activity, taken together with their reported lack of locomotor activity, provides a compelling argument for exploring this class of molecules further in animal behavioral experiments. The present work thus broadens the scope of structures that may be considered as lead structures in the search for cocaine abuse medications.
Kozikowski A P; Araldi G L; Boja J; Meil W M; Johnson K M; Flippen-Anderson J L; George C; Saiah E
Journal of Medicinal Chemistry
1998
1998-05
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1021/jm980028+" target="_blank" rel="noreferrer noopener">10.1021/jm980028+</a>
Inhibition Of Striatal Dopamine Transporter Activity By 17 Beta-estradiol
brain; dopamine transporter; estradiol; estrous-cycle; gonadal steroid hormone; h-3 gbr-12935 binding; mptp-induced neurotoxicity; nigrostriatal; nucleus-accumbens; Pharmacology & Pharmacy; progesterone; protein-kinase-c; release; sex-differences; striatal; synaptosome; uptake inhibition; uptake sites
Disshon K A; Boja J W; Dluzen D E
European Journal of Pharmacology
1998
1998-03
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1016/s0014-2999(98)00008-9" target="_blank" rel="noreferrer noopener">10.1016/s0014-2999(98)00008-9</a>
Dopamine Transporter As A Marker Of Neuroprotection In Methamphetamine-lesioned Mice Treated Acutely With Estradiol
17-beta-estradiol; brain; depletion; dopamine transporter; Endocrinology & Metabolism; estrogen; gender-differences; gonadal steroids; induced neurotoxicity; methamphetamine; neuroprotection; Neurosciences & Neurology; parkinsons-disease; progesterone; rat; striatal dopamine; striatum; substantia nigra; system
D'Astous M; Gajjar T M; Dluzen D E; Di Paolo T
Neuroendocrinology
2004
1905-06
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1159/000079664" target="_blank" rel="noreferrer noopener">10.1159/000079664</a>
Multiple binding sites for I-125 RTI-121 and other cocaine analogs in rat frontal cerebral cortex
Neurosciences & Neurology; localization; h-3 gbr-12935 binding; transporter; membranes; dopamine transporter; cocaine; nucleus-accumbens; norepinephrine transporter; medial prefrontal cortex; brain synaptosomes; glycosylation; human dopamine; reinforcing properties; RTI-121; self-stimulation; serotonin transporter; striatal
In an effort to identify novel binding sites for cocaine and its analogs, we carried out binding studies with the high-affinity and selective ligand [I-125]RTI-121 in rat frontal cortical tissue. Very low densities of binding sites were found. Saturation analysis revealed that the binding was to both high- and low-affinity sites. Pharmacological competition studies were carried out with inhibitors of the dopamine, norepinephrine, and serotonin transporters. The various transporter inhibitors inhibited the binding of 15 pM [I-125]RTI-121 in a biphasic fashion following a two-site binding model. The resultant data were complex and did not suggest a simple association with any single transporter. Correlational analysis supported the following hypothesis: [I-125] RTI-121 binds to known transporters and not to novel sites; these include dopamine, norepinephrine, and serotonin transporters. Immunoprecipitation of transporters photoaffinity labeled with [(125)] RTI-82 and subsequent analysis of SDS-page gels revealed the presence of authentic dopamine transporters in these samples; displacement of the photoaffinity label occurred with a typical dopamine transporter pharmacology. These data are compatible with the binding properties of RTI-181 and the presence of several known transporters in the tissue studied. Synapse 30:9-17, 1998. (C) 1998 Wiley-Liss, Inc.dagger
Boja J W; Carroll F I; Vaughan R A; Kopajtic T; Kuhar M J
Synapse
1998
1998-09
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1002/(sici)1098-2396(199809)30:1%3C9::aid-syn2%3E3.3.co;2-p" target="_blank" rel="noreferrer noopener">10.1002/(sici)1098-2396(199809)30:1%3C9::aid-syn2%3E3.3.co;2-p</a>
Oestrogen Receptors and Signalling Pathways: Implications for Neuroprotective Effects of Sex Steroids in Parkinson's Disease
17 ss-oestradiol; Akt; beta messenger-rna; central-nervous-system; dopamine transporter; Endocrinology & Metabolism; er-alpha; GPER1; growth-factor receptor; GSK3 ss; induced dopamine depletion; ischemic brain-injury; monoamine transporter; MPTP; Neurosciences & Neurology; plasma-membrane; protein-coupled receptor; rat-brain; vesicular
Parkinsons disease (PD) is an age-related neurodegenerative disorder with a higher incidence in the male population. In the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD, 17 beta-oestradiol but not androgens were shown to protect dopamine (DA) neurones. We report that oestrogen receptors (ER)a and beta distinctly contribute to neuroprotection against MPTP toxicity, as revealed by examining the membrane DA transporter (DAT), the vesicular monoamine transporter 2 (VMAT2) and tyrosine hyroxylase in ER wild-type (WT) and knockout (ERKO) C57Bl/6 male mice. Intact ERKO beta mice had lower levels of striatal DAT and VMAT2, whereas ERKOa mice were the most sensitive to MPTP toxicity compared to WT and ERKO beta mice and had the highest levels of plasma androgens. In both ERKO mice groups, treatment with 17 beta-oestradiol did not provide neuroprotection against MPTP, despite elevated plasma 17 beta-oestradiol levels. Next, the recently described membrane G protein-coupled oestrogen receptor (GPER1) was examined in female Macaca fascicularis monkeys and mice. GPER1 levels were increased in the caudate nucleus and the putamen of MPTP-monkeys and in the male mouse striatum lesioned with methamphetamine or MPTP. Moreover, neuroprotective mechanisms in response to oestrogens transmit via Akt/glycogen synthase kinase-3 (GSK3) signalling. The intact and lesioned striata of 17 beta-oestradiol treated monkeys, similar to that of mice, had increased levels of pAkt (Ser 473)/beta III-tubulin, pGSK3 (Ser 9)/beta III-tubulin and Akt/beta III-tubulin. Hence, ERa, ER beta and GPER1 activation by oestrogens is imperative in the modulation of ER signalling and serves as a basis for evaluating nigrostriatal neuroprotection.
Al Sweidi S; Sanchez M G; Bourque M; Morissette M; Dluzen D; Di Paolo T
Journal of Neuroendocrinology
2012
2012-01
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1111/j.1365-2826.2011.02193.x" target="_blank" rel="noreferrer noopener">10.1111/j.1365-2826.2011.02193.x</a>
Synthesis of 3 beta-(4- I-125 Iodophenyl)tropane-2 beta-pyrrolidine carboxamide ( I-125 RTI-229)
acid isopropyl ester; analogs; Biochemistry & Molecular Biology; brain; Chemistry; chloramine-T; cocaine; dopamine transporter; high-affinity; iodine-125 labelling; iododestannylation; ligand; nonhuman primates; Pharmacology & Pharmacy; radioiodination; RTI-229
A WIN 35,055-2 analog, 3 beta-(4-iodophenyl)tropane-2 beta-pyrrolidine carboxamide (RTI-229), has been radiolabelled with iodine-125 by radioiododestannylation of the corresponding trimethyltin derivative using carrier-free sodium iodide-125 as the isotope source. Purification by reversed-phase HPLC gives [I-125]RTI-229 in good yield (89.4%) with high radiochemical purity (>99%) and high specific activity (2125 mCi/mu mol, 78.6 GBq/mu mol, based on the specific activity of the (NaI)-I-125 used).
Zhong D S; Kotian P; Wyrick C D; Seltzman H H; Kepler J A; Boja J W; Kuhar M J; Carroll F I
Journal of Labelled Compounds & Radiopharmaceuticals
1999
1999-03
Journal Article
n/a
Valproate increases dopamine transporter expression through histone acetylation and enhanced promoter binding of Nurr1.
Acetylation/drug effects; Animals; Butyrates/pharmacology; Cell Line; Cell Survival/drug effects; Dopamine Plasma Membrane Transport Proteins/*metabolism; Dopamine transporter; Dopaminergic Neurons/cytology/drug effects/metabolism; Dose-Response Relationship; Drug; Epigenesis; Epigenetics; Genetic; Genetic/drug effects; Group A; HDAC; Histone deacetylase; Histone Deacetylase Inhibitors/*pharmacology; Histone Deacetylases/metabolism; Histones/*drug effects/metabolism; Homeodomain Proteins/metabolism; Hydroxamic Acids/pharmacology; Member 2/*metabolism; Messenger/metabolism; Nuclear Receptor Subfamily 4; Nurr1; Pitx3; Promoter Regions; Rats; RNA; Transcription Factors/metabolism; Valproate; Valproic Acid/*pharmacology
The dopamine transporter (DAT) is the key regulator of dopaminergic transmission and is a target of several xenobiotics, including pesticides and pharmacological agents. Previously, we identified a prominent role for histone deacetylases in the regulation of DAT expression. Here, we utilized a rat dopaminergic cell line (N27) to probe the responsiveness of DAT mRNA expression to inhibitors of histone acetylation. Inhibition of histone deacetylases (HDACs) by valproate, butyrate and Trichostatin A led to a 3-10-fold increase in DAT mRNA expression, a 50% increase in protein levels, which were accompanied by increased H3 acetylation levels. To confirm the mechanism of valproate-mediated increase in DAT mRNA, chromatin immunoprecipitation (ChIP) assays were used and demonstrated a significant increase in enrichment of acetylation of histone 3 on lysines 9 and 14 (H3K9/K14ac) in the DAT promoter. Expression of Nurr1 and Pitx3, key regulators of DAT expression, were increased following valproate treatment and Nurr1 binding was enriched in the DAT promoter. Together, these results indicate that histone acetylation and subsequent enhancement of transcription factor binding are plausible mechanisms for DAT regulation by valproate and, perhaps, by other xenobiotics.
Green Ashley L; Zhan Le; Eid Aseel; Zarbl Helmut; Guo Grace L; Richardson Jason R
Neuropharmacology
2017
2017-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.neuropharm.2017.07.020" target="_blank" rel="noreferrer noopener">10.1016/j.neuropharm.2017.07.020</a>
Single low doses of MPTP decrease tyrosine hydroxylase expression in the absence of overt neuron loss.
1-Methyl-4-phenyl-1; 2; 3; 6-tetrahydropyridine/*administration & dosage; Animals; Catecholamines/metabolism; Cell Count; Corpus Striatum/*drug effects/metabolism; Dopamine; Dopamine transporter; Dopaminergic Neurons/*drug effects/metabolism; Inbred C57BL; Male; Mice; MPTP; MPTP Poisoning; Parkinsonian Disorders/*metabolism/*pathology; Stereology; Substantia Nigra/*drug effects/metabolism; Tyrosine 3-Monooxygenase/*metabolism; Tyrosine hydroxylase; Vesicular monoamine transporter
Parkinson's disease (PD) is the second most common age-related neurodegenerative disease. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a prototypical neurotoxicant used in mice to mimic primary features of PD pathology including striatal dopamine depletion and dopamine neuron loss in the substantia nigra pars compacta (SNc). In the literature, there are several experimental paradigms involving multiple doses of MPTP that are used to elicit dopamine neuron loss. However, a recent study reported that a single low dose caused significant loss of dopamine neurons. Here, we determined the effect of a single intraperitoneal injection of one of three doses of MPTP (0.1, 2 and 20mg/kg) on dopamine neurons, labeled by tyrosine hydroxylase (TH(+)), and total neuron number (Nissl(+)) in the SNc using unbiased stereological counting. Data reveal a significant loss of neurons in the SNc (TH(+) and Nissl(+)) only in the group treated with 20mg/kg MPTP. Groups treated with lower dose of MPTP (0.1 and 2mg/kg) only showed significant loss of TH(+) neurons rather than TH(+) and Nissl(+) neurons. Striatal dopamine levels were decreased in the groups treated with 2 and 20mg/kg MPTP and striatal terminal markers including, TH and the dopamine transporter (DAT), were only decreased in the groups treated with 20mg/kg MPTP. These data demonstrate that lower doses of MPTP likely result in loss of TH expression rather than actual dopamine neuron loss in the SN. This finding reinforces the need to measure both total neuron number along with TH(+) cells in determining dopamine neuron loss.
Alam Gelareh; Edler Melissa; Burchfield Shelbie L; Richardson Jason R
Neurotoxicology
2017
2017-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.neuro.2017.03.008" target="_blank" rel="noreferrer noopener">10.1016/j.neuro.2017.03.008</a>