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1.
Transl Psychiatry ; 14(1): 41, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38242896

RESUMO

Ibogaine (IBO) is an atypical psychedelic with a complex mechanism of action. To date, the mechanisms that may underlie its anti-addictive effects are still not defined. This study aims to identify changes in gene expression induced by a single oral dose of IBO in the cortex of mice by means of a transcriptomic analysis for the first time. Our results showed significant alterations in gene expression in mouse frontal cortex samples 4 h after a single oral dose of IBO. Specifically, genes involved in hormonal pathways and synaptogenesis exhibited upregulation, while genes associated with apoptotic processes and endosomal transports showed downregulation. The findings were further corroborated through quantitative polymerase chain reaction (qPCR) analysis. However, the validation of gene expression related to hormonal pathways did not entirely align with the transcriptomic analysis results, possibly due to the brain region from which tissue was collected. Sex differences were observed, with female mice displaying more pronounced alterations in gene expression after IBO treatment. High variability was observed across individual animals. However, this study represents a significant advancement in comprehending IBO's molecular actions. The findings highlight the influence of IBO on gene expression, particularly on hormonal pathways, synaptogenesis, apoptotic processes, and endosomal transports. The identification of sex differences underscores the importance of considering sex as a potential factor influencing IBO's effects. Further research to assess different time points after IBO exposure is warranted.


Assuntos
Alucinógenos , Ibogaína , Camundongos , Feminino , Animais , Masculino , Ibogaína/metabolismo , Ibogaína/farmacologia , Alucinógenos/farmacologia , Córtex Cerebral/metabolismo , Encéfalo/metabolismo
2.
Planta Med ; 89(2): 148-157, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35338475

RESUMO

Plants of Tabernaemontana species have several pharmacological activities including antimicrobial effects. Amoebiasis continues to be a public health problem, with increasing evidence of resistance to metronidazole. In this study, we assessed the effect of the alkaloid fraction of T. arborea root bark and the alkaloids ibogaine and voacangine on the viability and infectivity of Entamoeba histolytica trophozoites. Cultures were exposed to 0.1 - 10 µg/mL for 24, 48 and 72 h, and viability was then determined using a tetrazolium dye reduction assay and type of cellular death analyzed by flow cytometry. Results showed that the alkaloid fraction, but mainly ibogaine and voacangine alkaloids, exhibited potent dose-dependent anti-amoebic activity at 24 h post-exposure (IC50 4.5 and 8.1 µM, respectively), comparable to metronidazole (IC50 6.8 µM). However, the effect decreased after 48 and 72 h of exposure to concentrations below 10 µg/mL, suggesting that the alkaloids probably were catabolized to less active derivatives by the trophozoites. The treatment of trophozoites with the IC50 s for 24 h induced significant morphological changes in the trophozoites, slight increase in granularity, and death by apoptonecrosis. The capacity of T. arborea alkaloids to inhibit the development of amoebic liver abscesses in hamsters was evaluated. Results showed that even when the treatments reduced the number of amoebic trophozoites in tissue sections of livers, they were unable to limit the formation of abscesses, suggesting their rapid processing to inactive metabolites. This work leaves open the possibility of using Tabernaemontana alkaloids as a new alternative for amoebiasis control.


Assuntos
Alcaloides , Amebíase , Ibogaína , Tabernaemontana , Ibogaína/metabolismo , Ibogaína/farmacologia , Metronidazol/farmacologia , Metronidazol/metabolismo , Casca de Planta , Alcaloides/farmacologia , Alcaloides/metabolismo
3.
Artigo em Inglês | MEDLINE | ID: mdl-32194202

RESUMO

To determine whether (+)-catharanthine induces sedative- or anxiolytic/anxiogenic-like activity in male mice, proper animal paradigms were used. The results showed that (+)-catharanthine induces sedative-like activity in the 63-72 mg/Kg dose range in a flumazenil-insensitive manner, but neither this effect nor anxiolytic/anxiogenic-like activity was observed at lower doses. To determine the underlying molecular mechanism of the sedative-like activity, electrophysiological and radioligand binding experiments were performed with (+)-catharanthine and (±)-18-methoxycoronaridine [(±)-18-MC] on GABAA (GABAARs) and glycine receptors (GlyRs). Coronaridine congeners both activated and potentiated a variety of human (h) GABAARs, except hρ1. (+)-Catharanthine-induced potentiation followed this receptor selectivity (EC50's in µM): hα1ß2 (4.6 ± 0.8) > hα2ß2γ2 (12.6 ± 3.8) ~ hα1ß2γ2 (14.4 ± 4.6) indicating that both α1 and α2 are equally important, whereas γ2 is not necessary. (+)-Catharanthine was >2-fold more potent and efficient than (±)-18-MC at hα1ß2γ2. (+)-Catharanthine also potentiated, whereas (±)-18-MC inhibited, hα1 GlyRs with very low potency. Additional [3H]-flunitrazepam competition binding experiments using rat cerebellum membranes clearly demonstrated that these ligands do not bind to the benzodiazepine site. This is supported by the observed activity at hα1ß2 (lacking the BDZ site) and similar effects between α1- and α2-containing GABAARs. Our study shows, for the first time, that (+)-catharanthine induced sedative-like effects in mice, and coronaridine congeners potentiated human α1ß2γ2, α1ß2, and hα2ß2γ2, but not ρ1, GABAARs, both in a benzodiazepine-insensitive fashion, whereas only (+)-catharanthine slightly potentiated GlyRs.


Assuntos
Benzodiazepinas/metabolismo , Hipnóticos e Sedativos/metabolismo , Ibogaína/análogos & derivados , Ibogaína/metabolismo , Receptores de GABA-A/metabolismo , Animais , Benzodiazepinas/farmacologia , Relação Dose-Resposta a Droga , Agonistas de Receptores de GABA-A/metabolismo , Agonistas de Receptores de GABA-A/farmacologia , Células HEK293 , Humanos , Hipnóticos e Sedativos/farmacologia , Ibogaína/farmacologia , Locomoção/efeitos dos fármacos , Locomoção/fisiologia , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos
4.
J Am Chem Soc ; 141(33): 12979-12983, 2019 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-31364847

RESUMO

(-)-Ibogaine and (-)-voacangine are plant derived psychoactives that show promise as treatments for opioid addiction. However, these compounds are produced by hard to source plants, making these chemicals difficult for broad-scale use. Here we report the complete biosynthesis of (-)-voacangine, and de-esterified voacangine, which is converted to (-)-ibogaine by heating, enabling biocatalytic production of these compounds. Notably, (-)-ibogaine and (-)-voacangine are of the opposite enantiomeric configuration compared to the other major alkaloids found in this natural product class. Therefore, this discovery provides insight into enantioselective enzymatic formal Diels-Alder reactions.


Assuntos
Ibogaína/análogos & derivados , Ibogaína/metabolismo , Psicotrópicos/metabolismo , Tabernaemontana/metabolismo , Vias Biossintéticas , Humanos , Ibogaína/análise , Transtornos Relacionados ao Uso de Opioides/tratamento farmacológico , Psicotrópicos/análise , Estereoisomerismo , Tabernaemontana/química , Tabernaemontana/enzimologia
5.
Nat Commun ; 10(1): 1687, 2019 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-30976000

RESUMO

The serotonin transporter (SERT), a member of the neurotransmitter:sodium symporter family, is responsible for termination of serotonergic signaling by re-uptake of serotonin (5-HT) into the presynaptic neuron. Its key role in synaptic transmission makes it a major drug target, e.g. for the treatment of depression, anxiety and post-traumatic stress. Here, we apply hydrogen-deuterium exchange mass spectrometry to probe the conformational dynamics of human SERT in the absence and presence of known substrates and targeted drugs. Our results reveal significant changes in dynamics in regions TM1, EL3, EL4, and TM12 upon binding co-transported ions (Na+/K+) and ligand-mediated changes in TM1, EL3 and EL4 upon binding 5-HT, the drugs S-citalopram, cocaine and ibogaine. Our results provide a comprehensive direct view of the conformational response of SERT upon binding both biologically relevant substrate/ions and ligands of pharmaceutical interest, thus advancing our understanding of the structure-function relationship in SERT.


Assuntos
Domínios Proteicos , Proteínas da Membrana Plasmática de Transporte de Serotonina/química , Cátions Monovalentes/metabolismo , Citalopram/química , Citalopram/metabolismo , Cocaína/química , Cocaína/metabolismo , Ibogaína/química , Ibogaína/metabolismo , Ligantes , Espectrometria de Massas , Simulação de Dinâmica Molecular , Potássio/metabolismo , Ligação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Serotonina/química , Serotonina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/isolamento & purificação , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Sódio/metabolismo , Relação Estrutura-Atividade
6.
Int J Biochem Cell Biol ; 92: 202-209, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29042244

RESUMO

The inhibitory activity of coronaridine congeners on human (h) α4ß2 and α7 nicotinic acetylcholine receptors (AChRs) is determined by Ca2+ influx assays, whereas their effects on neurons in the ventral inferior (VI) aspect of the mouse medial habenula (MHb) are determined by patch-clamp recordings. The Ca2+ influx results clearly establish that coronaridine congeners inhibit hα3ß4 AChRs with higher selectivity compared to hα4ß2 and hα7 subtypes, and with the following potency sequence, for hα4ß2: (±)-18-methoxycoronaridine [(±)-18-MC]>(+)-catharanthine>(±)-18-methylaminocoronaridine [(±)-18-MAC] ∼ (±)-18-hydroxycoronaridine [(±)-18-HC]; and for hα7: (+)-catharanthine>(±)-18-MC>(±)-18-HC>(±)-18-MAC. Interestingly, the inhibitory potency of (+)-catharanthine (27±4µM) and (±)-18-MC (28±6µM) on MHb (VI) neurons was lower than that observed on hα3ß4 AChRs, suggesting that these compounds inhibit a variety of endogenous α3ß4* AChRs. In addition, the interaction of bupropion with (-)-ibogaine sites on hα3ß4 AChRs is tested by [3H]ibogaine competition binding experiments. The results indicate that bupropion binds to ibogaine sites at desensitized hα3ß4 AChRs with 2-fold higher affinity than at resting receptors, suggesting that these compounds share the same binding sites. In conclusion, coronaridine congeners inhibit hα3ß4 AChRs with higher selectivity compared to other AChRs, by interacting with the bupropion (luminal) site. Coronaridine congeners also inhibit α3ß4*AChRs expressed in MHb (VI) neurons, supporting the notion that these receptors are important endogenous targets for their anti-addictive activities.


Assuntos
Habenula/efeitos dos fármacos , Habenula/metabolismo , Ibogaína/análogos & derivados , Antagonistas Nicotínicos/química , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Animais , Ibogaína/química , Ibogaína/metabolismo , Ibogaína/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Antagonistas Nicotínicos/metabolismo , Conformação Proteica , Receptores Nicotínicos/química
7.
Behav Brain Res ; 330: 63-67, 2017 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-28479267

RESUMO

Noribogaine is the main psychoactive metabolite of the hallucinogenic drug ibogaine, and is a particularly interesting compound potentially useful to treat dependence and various psychiatric disorders. Here, we report the effects of noribogaine on anxiety and locomotion in zebrafish (Danio rerio), a new promising model organism in neurobehavioral and psychopharmacological research. Adult zebrafish were subjected to the 5min novel tank test (NTT) following an acute, 20-min drug immersion in 1, 5 and 10mg/L noribogaine. Overall, noribogaine produced robust anxiolytic-like behavior in zebrafish (increasing the time spent and transitions to the top half compartment and reducing freezing bouts) without overt effects on fish locomotion. Taken together, these results indicate that noribogaine modulates the components of the acute stress response related to emotionality and anxiety behaviors, implicating this drug as a potentially useful non-sedative anxiolytic agent.


Assuntos
Ibogaína/análogos & derivados , Estresse Fisiológico/efeitos dos fármacos , Animais , Ansiolíticos/metabolismo , Ansiolíticos/farmacologia , Ansiedade/tratamento farmacológico , Transtornos de Ansiedade/tratamento farmacológico , Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Alucinógenos/farmacologia , Ibogaína/metabolismo , Ibogaína/farmacologia , Locomoção/efeitos dos fármacos , Masculino , Peixe-Zebra/metabolismo , Peixe-Zebra/fisiologia
8.
Pol Merkur Lekarski ; 41(241): 50-55, 2016 Jul 29.
Artigo em Polonês | MEDLINE | ID: mdl-27734823

RESUMO

Ibogaine is a natural chemical compound, which belongs to the indole alkaloid family. It can be naturally found within the root bark of african plant Tabernanthe iboga. Ibogaine plays a significant role among tribal cultures. Ibogaine, in small amount, causes reduction of hunger, thirst and exhaustion. In bigger amount, however, it can cause intensive visions. Other effects include reduction or complete disappearance of absitnence symptoms visible in people addicted to the nicotine, alcohol, methamphetamine, cocaine or opioids, what has been scientifically proven after the tests on animals and small groups of people. After oral application, 80% of ibogaine is subjected to the Odemethylation into noribogaine; main catalyzing enzyme is cytochrome CYP2D6. Research suggests, that ibogaine acts in many places within central nervous system. NMDA receptors seem to play main role in its anti-addiction properties. It is important to mention the side effects of the compound, which are cardiotoxicity and neurotoxicity, what makes it harder to use its beneficial properties. Because of this, Ibogaine is included among the dangerous substance. However, there are a few clinics in the world which specializes in the use of the compound in order to interrupt the sypmtoms acute opioid withdrawal syndrome as well as a substance benficial in curing other addictions. There is more hope with synthetic derivatives of ibogaine, which although are less toxic still keep their anti-addiction properties. The aim is to collect the available knowledge related to the structure and effects on human body of alkaloid Tabernanthe iboga and consider the possibility of commercial medical use.


Assuntos
Ibogaína/uso terapêutico , Cardiotoxicidade/etiologia , Humanos , Ibogaína/efeitos adversos , Ibogaína/análogos & derivados , Ibogaína/metabolismo , Ibogaína/farmacologia , Síndromes Neurotóxicas/etiologia , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico
9.
J Pharm Biomed Anal ; 115: 467-74, 2015 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-26298394

RESUMO

Previous investigations demonstrated that pretreatment with non-cytotoxic concentrations of voacamine had a chemosensitizing effect on cultured multidrug resistant osteosarcoma cells exposed to doxorubicin; whereas when used alone at high concentrations voacamine induced apoptosis-independent cell death on both sensitive and resistant cells. To gain insight into the mechanism of action of voacamine at the subcellular level, we developed an analytical high-performance thin-layer chromatography technique to assess the intracellular content of voacamine that could be correlated with the induction of cell death and consequent morphological and ultrastructural changes. The results of the quantitative analysis not only did allow us to measure both the amount of unmodified voacamine molecules (determined by the method) and the amount of molecules which reacted with cellular components (undetectable), but also to confirm the findings of our previous studies and support the validity of this method.


Assuntos
Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/metabolismo , Cromatografia em Camada Fina/métodos , Ibogaína/análogos & derivados , Osteossarcoma/tratamento farmacológico , Osteossarcoma/metabolismo , Apoptose/efeitos dos fármacos , Transporte Biológico , Neoplasias Ósseas/ultraestrutura , Linhagem Celular Tumoral , Forma Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos , Humanos , Ibogaína/metabolismo , Ibogaína/farmacologia , Osteossarcoma/ultraestrutura , Reprodutibilidade dos Testes
10.
Int J Biochem Cell Biol ; 65: 81-90, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26022277

RESUMO

To characterize the interaction of coronaridine congeners with human (h) α3ß4 nicotinic acetylcholine receptors (AChRs), structural and functional approaches were used. The Ca(2+) influx results established that coronaridine congeners noncompetitively inhibit hα3ß4 AChRs with the following potency (IC50's in µM) sequence: (-)-ibogamine (0.62±0.23)∼(+)-catharanthine (0.68±0.10)>(-)-ibogaine (0.95±0.10)>(±)-18-methoxycoronaridine [(±)-18-MC] (1.47±0.21)>(-)-voacangine (2.28±0.33)>(±)-18-methylaminocoronaridine (2.62±0.57 µM)∼(±)-18-hydroxycoronaridine (2.81±0.54)>(-)-noribogaine (6.82±0.78). A good linear correlation (r(2)=0.771) between the calculated IC50 values and their polar surface area was found, suggesting that this is an important structural feature for its activity. The radioligand competition results indicate that (±)-18-MC and (-)-ibogaine partially inhibit [(3)H]imipramine binding by an allosteric mechanism. Molecular docking, molecular dynamics, and in silico mutation results suggest that protonated (-)-18-MC binds to luminal [i.e., ß4-Phe255 (phenylalanine/valine ring; position 13'), and α3-Leu250 and ß4-Leu251 (leucine ring; position 9')], non-luminal, and intersubunit sites. The pharmacophore model suggests that nitrogens from the ibogamine core as well as methylamino, hydroxyl, and methoxyl moieties at position 18 form hydrogen bonds. Collectively our data indicate that coronaridine congeners inhibit hα3ß4 AChRs by blocking the ion channel's lumen and probably by additional negative allosteric mechanisms by interacting with a series of non-luminal sites.


Assuntos
Ibogaína/análogos & derivados , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Regulação Alostérica , Ligação Competitiva , Células HEK293 , Humanos , Ibogaína/química , Ibogaína/metabolismo , Ibogaína/farmacologia , Modelos Moleculares , Simulação de Dinâmica Molecular , Antagonistas Nicotínicos/química , Antagonistas Nicotínicos/metabolismo , Ensaio Radioligante , Receptores Nicotínicos/química , Relação Estrutura-Atividade
11.
J Clin Pharmacol ; 55(6): 680-7, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25651476

RESUMO

Conversion of ibogaine to its active metabolite noribogaine appears to be mediated primarily by CYP2D6. We compared 168 hours pharmacokinetic profiles of both analytes after a single oral 20 mg dose of ibogaine in 21 healthy subjects who had been pretreated for 6 days with placebo or the CYP2D6 inhibitor paroxetine. In placebo-pretreated subjects, ibogaine was rapidly converted to noribogaine. Median peak noribogaine concentrations occurred at 4 hours. Compared with placebo-pretreated subjects, paroxetine-pretreated subjects had rapid (Tmax = 1.5 hours) and substantial absorption of ibogaine, with detectable levels out to 72 hours, and an elimination half-life of 10.2 hours. In this group, ibogaine was also rapidly converted to noribogaine with a median Tmax of 3 hours. Extent of noribogaine exposure was similar in both groups. CYP2D6 phenotype was robustly correlated with ibogaine AUC0-t (r = 0.82) and Cmax (r = 0.77). Active moiety (ibogaine plus noribogaine) exposure was ∼2-fold higher in paroxetine-pretreated subjects. Single 20 mg ibogaine doses were safe and well tolerated in all subjects. The doubling of exposure to active moiety in subjects with reduced CYP2D6 activity suggests it may be prudent to genotype patients awaiting ibogaine treatment, and to at least halve the intended dose of ibogaine in CYP2D6 poor metabolizers.


Assuntos
Citocromo P-450 CYP2D6/metabolismo , Voluntários Saudáveis , Ibogaína/análogos & derivados , Ibogaína/farmacocinética , Paroxetina/farmacocinética , Adulto , Inibidores do Citocromo P-450 CYP2D6/farmacocinética , Relação Dose-Resposta a Droga , Interações Medicamentosas , Antagonistas de Aminoácidos Excitatórios/farmacocinética , Feminino , Meia-Vida , Humanos , Ibogaína/administração & dosagem , Ibogaína/análise , Ibogaína/metabolismo , Masculino , Paroxetina/administração & dosagem , Fatores de Tempo , Adulto Jovem
12.
J Biol Chem ; 287(22): 18524-34, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-22451652

RESUMO

Ibogaine, a hallucinogenic alkaloid proposed as a treatment for opiate withdrawal, has been shown to inhibit serotonin transporter (SERT) noncompetitively, in contrast to all other known inhibitors, which are competitive with substrate. Ibogaine binding to SERT increases accessibility in the permeation pathway connecting the substrate-binding site with the cytoplasm. Because of the structural similarity between ibogaine and serotonin, it had been suggested that ibogaine binds to the substrate site of SERT. The results presented here show that ibogaine binds to a distinct site, accessible from the cell exterior, to inhibit both serotonin transport and serotonin-induced ionic currents. Ibogaine noncompetitively inhibited transport by both SERT and the homologous dopamine transporter (DAT). Ibogaine blocked substrate-induced currents also in DAT and increased accessibility of the DAT cytoplasmic permeation pathway. When present on the cell exterior, ibogaine inhibited SERT substrate-induced currents, but not when it was introduced into the cytoplasm through the patch electrode. Similar to noncompetitive transport inhibition, the current block was not reversed by increasing substrate concentration. The kinetics of inhibitor binding and dissociation, as determined by their effect on SERT currents, indicated that ibogaine does not inhibit by forming a long-lived complex with SERT, but rather binds directly to the transporter in an inward-open conformation. A kinetic model for transport describing the noncompetitive action of ibogaine and the competitive action of cocaine accounts well for the results of the present study.


Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/antagonistas & inibidores , Antagonistas de Aminoácidos Excitatórios/farmacologia , Ibogaína/farmacologia , Proteínas da Membrana Plasmática de Transporte de Serotonina/efeitos dos fármacos , Animais , Sítios de Ligação , Linhagem Celular , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Antagonistas de Aminoácidos Excitatórios/metabolismo , Humanos , Ibogaína/metabolismo , Cinética , Técnicas de Patch-Clamp , Ensaio Radioligante , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Xenopus laevis
13.
Mol Pharmacol ; 78(6): 1026-35, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20829432

RESUMO

The structure of the bacterial leucine transporter from Aquifex aeolicus (LeuT(Aa)) has been used as a model for mammalian Na(+)/Cl(-)-dependent transporters, in particular the serotonin transporter (SERT). The crystal structure of LeuT(Aa) liganded to tricyclic antidepressants predicts simultaneous binding of inhibitor and substrate. This is incompatible with the mutually competitive inhibition of substrates and inhibitors of SERT. We explored the binding modes of tricyclic antidepressants by homology modeling and docking studies. Two approaches were used subsequently to differentiate between three clusters of potential docking poses: 1) a diagnostic SERT(Y95F) mutation, which greatly reduced the affinity for [(3)H]imipramine but did not affect substrate binding; 2) competition binding experiments in the presence and absence of carbamazepine (i.e., a tricyclic imipramine analog with a short side chain that competes with [(3)H]imipramine binding to SERT). Binding of releasers (para-chloroamphetamine, methylene-dioxy-methamphetamine/ecstasy) and of carbamazepine were mutually exclusive, but Dixon plots generated in the presence of carbamazepine yielded intersecting lines for serotonin, MPP(+), paroxetine, and ibogaine. These observations are consistent with a model, in which 1) the tricyclic ring is docked into the outer vestibule and the dimethyl-aminopropyl side chain points to the substrate binding site; 2) binding of amphetamines creates a structural change in the inner and outer vestibule that precludes docking of the tricyclic ring; 3) simultaneous binding of ibogaine (which binds to the inward-facing conformation) and of carbamazepine is indicative of a second binding site in the inner vestibule, consistent with the pseudosymmetric fold of monoamine transporters. This may be the second low-affinity binding site for antidepressants.


Assuntos
Antidepressivos Tricíclicos/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/química , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Anfetaminas/metabolismo , Antidepressivos Tricíclicos/química , Sítios de Ligação/fisiologia , Carbamazepina/metabolismo , Células HEK293 , Humanos , Ibogaína/metabolismo , Paroxetina/metabolismo , Ligação Proteica/fisiologia
14.
Int J Biochem Cell Biol ; 42(9): 1525-35, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20684041

RESUMO

The interaction of ibogaine and phencyclidine (PCP) with human (h) alpha3beta4-nicotinic acetylcholine receptors (AChRs) in different conformational states was determined by functional and structural approaches including, radioligand binding assays, Ca2+ influx detections, and thermodynamic and kinetics measurements. The results established that (a) ibogaine inhibits (+/-)-epibatidine-induced Ca2+ influx in h(alpha)3beta4 AChRs with approximately 9-fold higher potency than that for PCP, (b) [3H]ibogaine binds to a single site in the h(alpha)3beta4 AChR ion channel with relatively high affinity (Kd = 0.46 +/- 0.06 microM), and ibogaine inhibits [3H]ibogaine binding to the desensitized h(alpha)3beta4 AChR with slightly higher affinity compared to the resting AChR. This is explained by a slower dissociation rate from the desensitized ion channel compared to the resting ion channel, and (c) PCP inhibits [3H]ibogaine binding to the h(alpha)3beta4 AChR, suggesting overlapping sites. The experimental results correlate with the docking simulations suggesting that ibogaine and PCP interact with a binding domain located between the serine (position 6') and valine/phenylalanine (position 13') rings. This interaction is mediated mainly by van der Waals contacts, which is in agreement with the observed enthalpic contribution determined by non-linear chromatography. However, the calculated entropic contribution also indicates local conformational changes. Collectively our data suggest that ibogaine and PCP bind to overlapping sites located between the serine and valine/phenylalanine rings, to finally block the AChR ion channel, and in the case of ibogaine, to probably maintain the AChR in the desensitized state for longer time.


Assuntos
Ibogaína/metabolismo , Receptores Nicotínicos/química , Receptores Nicotínicos/metabolismo , Transporte Biológico/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Cálcio/metabolismo , Linhagem Celular , Humanos , Cinética , Fenciclidina/farmacologia , Ligação Proteica , Estrutura Secundária de Proteína , Piridinas/farmacologia , Termodinâmica
15.
Neurochem Int ; 57(2): 153-61, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20493225

RESUMO

We compared the interaction of several catharanthine alkaloids including, ibogaine, vincristine, and vinblastine, with that for the noncompetitive antagonist phencyclidine (PCP) at muscle nicotinic acetylcholine receptors (AChRs) in different conformational states. The results established that catharanthine alkaloids: (a) inhibit, in a noncompetitive manner, (+/-)-epibatidine-induced Ca(2+) influx in TE671-halpha1beta1gammadelta cells with similar potencies (IC(50)=17-25microM), (b) inhibit [(3)H]TCP binding to the desensitized Torpedo AChR with higher affinity compared to the resting AChR, and (c) enhance [(3)H]cytisine binding to resting but activatable Torpedo AChRs, suggesting desensitizing properties. Interestingly, PCP inhibits [(3)H]ibogaine binding to the AChR in a steric fashion. This is corroborated by additional docking experiments indicating that the amino groups of neutral ibogaine form hydrogen bonds with the serine ring (position 6'), a location shared with PCP. Since protonated ibogaine forms a salt bridge with one of the acidic residues at the outer ring (position 20'), this ligand could be first attracted to the entrance of the channel by electrostatic interactions. Our data indicate that the catharanthine moiety is a minimum structural requirement for AChR inhibition including, ion channel blocking and desensitization, and that ibogaine and PCP bind to overlapping sites in the desensitized AChR ion channel.


Assuntos
Músculos/efeitos dos fármacos , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Alcaloides de Vinca/farmacologia , Animais , Cálcio/metabolismo , Linhagem Celular , Humanos , Ibogaína/metabolismo , Canais Iônicos/metabolismo , Transporte de Íons , Músculos/metabolismo , Ensaio Radioligante , Torpedo , Trítio
16.
Int J Neuropsychopharmacol ; 13(7): 905-15, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19887017

RESUMO

Drug interaction with P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) may influence its tissue disposition including blood-brain barrier transport and result in potent drug-drug interactions. The limited data obtained using in-vitro models indicate that methadone, buprenorphine, and cannabinoids may interact with human P-gp; but almost nothing is known about drugs of abuse and BCRP. We used in vitro P-gp and BCRP inhibition flow cytometric assays with hMDR1- and hBCRP-transfected HEK293 cells to test 14 compounds or metabolites frequently involved in addiction, including buprenorphine, norbuprenorphine, methadone, ibogaine, cocaine, cocaethylene, amphetamine, N-methyl-3,4-methylenedioxyamphetamine, 3,4-methylenedioxyamphetamine, nicotine, ketamine, Delta9-tetrahydrocannabinol (THC), naloxone, and morphine. Drugs that in vitro inhibited P-gp or BCRP were tested in hMDR1- and hBCRP-MDCKII bidirectional transport studies. Human P-gp was significantly inhibited in a concentration-dependent manner by norbuprenorphine>buprenorphine>methadone>ibogaine and THC. Similarly, BCRP was inhibited by buprenorphine>norbuprenorphine>ibogaine and THC. None of the other tested compounds inhibited either transporter, even at high concentration (100 microm). Norbuprenorphine (transport efflux ratio approoximately 11) and methadone (transport efflux ratio approoximately 1.9) transport was P-gp-mediated; however, with no significant stereo-selectivity regarding methadone enantiomers. BCRP did not transport any of the tested compounds. However, the clinical significance of the interaction of norbuprenorphine with P-gp remains to be evaluated.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Buprenorfina/análogos & derivados , Buprenorfina/metabolismo , Ibogaína/metabolismo , Drogas Ilícitas/metabolismo , Proteínas de Neoplasias/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Linhagem Celular Tumoral/metabolismo , Interações Medicamentosas , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Humanos
17.
J Anal Toxicol ; 30(7): 434-40, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16959135

RESUMO

In the present paper, we report for the first time the tissue distribution of ibogaine and noribogaine, the main metabolite of ibogaine, in a 48-year-old Caucasian male, with a history of drug abuse, found dead at his home after a poisoning involving the ingestion of root bark from the shrub Tabernanthe iboga. Ibogaine and noribogaine were quantified in tissues and fluids using a fully validated liquid chromatography-electrospray mass spectrometry method. Apart from cardiac tissue, ibogaine and noribogaine were identified in all matrices investigated. The highest concentrations were found in spleen, liver, brain, and lung. The tissue/subclavian blood concentration ratios averaged 1.78, 3.75, 1.16, and 4.64 for ibogaine and 0.83, 2.43, 0.90, and 2.69 for noribogaine for spleen, liver, brain, and lung, respectively. Very low concentrations of the two drugs were found in the prostatic tissue. Both ibogaine and noribogaine are secreted in the bile and cross the blood-brain barrier. Four other compounds were detected in most of the studied matrices. One of them was identified as ibogamine. Unfortunately, we were not able to positively identify the other three compounds because of the unavailability of reference substances. Two of them could possibly be attributed to the following oxidation products: iboluteine and desmethoxyiboluteine. The third compound could be ibogaline.


Assuntos
Ibogaína/análogos & derivados , Medicinas Tradicionais Africanas , Extratos Vegetais/intoxicação , Intoxicação por Plantas/metabolismo , Tabernaemontana , Cromatografia Líquida , Medicina Legal , Humanos , Ibogaína/metabolismo , Ibogaína/intoxicação , Masculino , Pessoa de Meia-Idade , Casca de Planta , Extratos Vegetais/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Distribuição Tecidual
19.
Rev Neurosci ; 16(4): 277-85, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16519005

RESUMO

Biochemical adaptations to drugs of abuse and alcohol are especially profound in midbrain dopaminergic neurons. Long-lasting molecular and structural changes in mesolimbic dopaminergic neurons that result from chronic exposure to drugs of abuse and alcohol are thought to underlie adverse behaviors such as compulsive drug seeking and relapse. Recent studies suggest that a subset of these changes is prevented/reversed by activation of the glial cell line-derived neurotrophic factor (GDNF) signaling pathway. Behavioral effects of drugs of abuse such as cocaine and alcohol are also negatively regulated by GDNF: inhibition of the endogenous GDNF pathway enhances the activity of drugs of abuse, while administration of GDNF reduces the severity of the effects. In this review, we summarize the data implicating GDNF as a negative regulator of drug and alcohol addiction. We also provide evidence to suggest that therapies that activate GDNF signaling may be useful for the treatment of drug and alcohol addiction.


Assuntos
Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Transdução de Sinais/fisiologia , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Antagonistas de Aminoácidos Excitatórios/metabolismo , Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Humanos , Ibogaína/metabolismo , Ibogaína/uso terapêutico , Microdomínios da Membrana/metabolismo , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico
20.
Medicina (Kaunas) ; 40(3): 216-9, 2004.
Artigo em Lituano | MEDLINE | ID: mdl-15064541

RESUMO

The review of scientific literature, concerning the indol alkaloid Ibogaine, which is extracted from the bush Tabernanthe Iboga, is presented in this article. Used as a stimulating factor for hundred of years in non-traditional medicine, this alkaloid could be important for modern pharmacology because of potential anti-addictive properties. The mechanism of action of this alkaloid is closely related to different neurotransmitting systems. Studies with animals allow concluding that Ibogaine or medicines based on this alkaloid can be used for treatment of drug dependencies.


Assuntos
Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Alucinógenos/uso terapêutico , Ibogaína/uso terapêutico , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico , Animais , Antagonistas de Aminoácidos Excitatórios/administração & dosagem , Antagonistas de Aminoácidos Excitatórios/metabolismo , Antagonistas de Aminoácidos Excitatórios/farmacocinética , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Cobaias , Alucinógenos/administração & dosagem , Alucinógenos/metabolismo , Alucinógenos/farmacocinética , Alucinógenos/farmacologia , Humanos , Ibogaína/administração & dosagem , Ibogaína/metabolismo , Ibogaína/farmacocinética , Ibogaína/farmacologia , Masculino , Camundongos , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
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