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Gibbs E, Chakrapani S. Structure, Function and Physiology of 5-Hydroxytryptamine Receptors Subtype 3. Subcell Biochem 2021; 96:373-408. [PMID: 33252737 DOI: 10.1007/978-3-030-58971-4_11] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
5-hydroxytryptamine receptor subtype 3 (5-HT3R) is a pentameric ligand-gated ion channel (pLGIC) involved in neuronal signaling. It is best known for its prominent role in gut-CNS signaling though there is growing interest in its other functions, particularly in modulating non-serotonergic synaptic activity. Recent advances in structural biology have provided mechanistic understanding of 5-HT3R function and present new opportunities for the field. This chapter gives a broad overview of 5-HT3R from a physiological and structural perspective and then discusses the specific details of ion permeation, ligand binding and allosteric coupling between these two events. Biochemical evidence is summarized and placed within a physiological context. This perspective underscores the progress that has been made as well as outstanding challenges and opportunities for future 5-HT3R research.
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Affiliation(s)
- Eric Gibbs
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, 44106-4970, USA.
| | - Sudha Chakrapani
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, 44106-4970, USA. .,Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106-4970, USA.
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2
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Castro MJ, Turani O, Faraoni MB, Gerbino D, Bouzat C. A New Antagonist of Caenorhabditis elegans Glutamate-Activated Chloride Channels With Anthelmintic Activity. Front Neurosci 2020; 14:879. [PMID: 32973433 PMCID: PMC7466757 DOI: 10.3389/fnins.2020.00879] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Nematode parasitosis causes significant mortality and morbidity in humans and considerable losses in livestock and domestic animals. The acquisition of resistance to current anthelmintic drugs has prompted the search for new compounds for which the free-living nematode Caenorhabditis elegans has emerged as a valuable platform. We have previously synthetized a small library of oxygenated tricyclic compounds and determined that dibenzo[b,e]oxepin-11(6H)-one (doxepinone) inhibits C. elegans motility. Because doxepinone shows potential anthelmintic activity, we explored its behavioral effects and deciphered its target site and mechanism of action on C. elegans. Doxepinone reduces swimming rate, induces paralysis, and decreases the rate of pharyngeal pumping required for feeding, indicating a marked anthelmintic activity. To identify the main drug targets, we performed an in vivo screening of selected strains carrying mutations in Cys-loop receptors involved in worm locomotion for determining resistance to doxepinone effects. A mutant strain that lacks subunit genes of the invertebrate glutamate-gated chloride channels (GluCl), which are targets of the widely used antiparasitic ivermectin (IVM), is resistant to doxepinone effects. To unravel the molecular mechanism, we measured whole-cell currents from GluClα1/β receptors expressed in mammalian cells. Glutamate elicits macroscopic currents whereas no responses are elicited by doxepinone, indicating that it is not an agonist of GluCls. Preincubation of the cell with doxepinone produces a statistically significant decrease of the decay time constant and net charge of glutamate-elicited currents, indicating that it inhibits GluCls, which contrasts to IVM molecular actions. Thus, we identify doxepinone as an attractive scaffold with promising anthelmintic activity and propose the inhibition of GluCls as a potential anthelmintic mechanism of action.
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Affiliation(s)
- María Julia Castro
- Departamento de Biología, Bioquímica y Farmacia, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina.,Instituto de Química del Sur (INQUISUR), Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Ornella Turani
- Departamento de Biología, Bioquímica y Farmacia, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - María Belén Faraoni
- Instituto de Química del Sur (INQUISUR), Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Darío Gerbino
- Instituto de Química del Sur (INQUISUR), Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Cecilia Bouzat
- Departamento de Biología, Bioquímica y Farmacia, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
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3
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Stuebler AG, Jansen M. Bupropion Inhibits Serotonin Type 3AB Heteromeric Channels at Clinically Relevant Concentrations. Mol Pharmacol 2019; 97:171-179. [PMID: 31871303 PMCID: PMC6978693 DOI: 10.1124/mol.119.118349] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/13/2019] [Indexed: 11/22/2022] Open
Abstract
Bupropion, a Food and Drug Administration–approved antidepressant and smoking cessation aid, blocks dopamine and norepinephrine reuptake transporters and noncompetitively inhibits nicotinic acetylcholine and serotonin (5-HT) type 3A receptors (5-HT3ARs). 5-HT3 receptors are pentameric ligand-gated ion channels that regulate synaptic activity in the central and peripheral nervous system, presynaptically and postsynaptically. In the present study, we examined and compared the effect of bupropion and its active metabolite hydroxybupropion on mouse homomeric 5-HT3A and heteromeric 5-HT3AB receptors expressed in Xenopus laevis oocytes using two-electrode voltage clamp experiments. Coapplication of bupropion or hydroxybupropion with 5-HT dose dependently inhibited 5-HT–induced currents in heteromeric 5-HT type 3AB receptors (5-HT3ABRs) (IC50 = 840 and 526 μM, respectively). The corresponding IC50s for bupropion and hydroxybupropion for homomeric 5-HT3ARs were 10- and 5-fold lower, respectively (87 and 113 μM). The inhibition of 5-HT3ARs and 5-HT3ABRs was non–use dependent and voltage independent, suggesting bupropion is not an open channel blocker. The inhibition by bupropion was reversible and time-dependent. Of note, preincubation with a low concentration of bupropion that mimics therapeutic drug conditions inhibits 5-HT–induced currents in 5-HT3A and 5-HT3AB receptors considerably. In summary, we demonstrate that bupropion inhibits heteromeric 5-HT3ABRs as well as homomeric 5-HT3ARs. This inhibition occurs at clinically relevant concentrations and may contribute to bupropion’s clinical effects.
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Affiliation(s)
- Antonia G Stuebler
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Michaela Jansen
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
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4
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Ono H, Okamura M, Fukushima A. [Similarity of Clinically Significant Neuropsychiatric Adverse Reactions Listed in Package Inserts between the Anti-influenza Drugs Oseltamivir and Amantadine (Possibility Attributable to Common Pharmacological Effects)]. YAKUGAKU ZASSHI 2018; 138:1201-1215. [PMID: 29925727 DOI: 10.1248/yakushi.18-00022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The anti-influenza virus drug oseltamivir has been reported to have several pharmacological actions including blocking of nicotinic acetylcholine receptor channels and activation of the dopaminergic system. These pharmacological actions highly overlap those of amantadine, another anti-influenza virus drug authorized in Japan, and ester-type local anesthetics. Moreover, oseltamivir and amantadine can clinically induce similar adverse neuropsychiatric reactions. In the present study, from the database of the Pharmaceuticals and Medical Devices Agency (PMDA), we surveyed 2576 drugs for which neuropsychiatric side effects similar to those of oseltamivir, amantadine and local anesthetics (abnormal behavior, confusion, consciousness disturbance, convulsion, delirium, delusion, hallucination, myoclonus, tremor) are listed as "clinically significant adverse reactions", and found 327 that had at least one of these adverse reactions. Other neuraminidase inhibitors (laninamivir, peramivir and zanamivir) did not elicit such adverse reactions. By discussing the pharmacological effects of drugs that elicit these adverse reactions, we propose that the similarity of adverse neuropsychiatric reactions between oseltamivir and amantadine is possibly attributable to their common pharmacological effects.
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Affiliation(s)
- Hideki Ono
- Laboratory of Clinical Pharmacy and Pharmacology, Faculty of Pharmacy, Musashino University.,Research Institute of Pharmaceutical Sciences, Musashino University
| | - Maya Okamura
- Laboratory of Clinical Pharmacy and Pharmacology, Faculty of Pharmacy, Musashino University
| | - Akihiro Fukushima
- Laboratory of Clinical Pharmacy and Pharmacology, Faculty of Pharmacy, Musashino University.,Research Institute of Pharmaceutical Sciences, Musashino University
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5
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Park YS, Myeong SH, Kim IB, Sung KW. Tricyclic antidepressant amitriptyline inhibits 5-hydroxytryptamine 3 receptor currents in NCB-20 cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2018; 22:585-595. [PMID: 30181705 PMCID: PMC6115347 DOI: 10.4196/kjpp.2018.22.5.585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/22/2018] [Accepted: 07/01/2018] [Indexed: 12/29/2022]
Abstract
Amitriptyline, a tricyclic antidepressant, is commonly used to treat depression and neuropathic pain, but its mechanism is still unclear. We tested the effect of amitriptyline on 5-hydroxytryptamine 3 (5-HT3) receptor currents and studied its blocking mechanism because the clinical applications of amitriptyline overlapped with 5-HT3 receptor therapeutic potentials. Using a whole-cell voltage clamp method, we recorded the currents of the 5-HT3 receptor when 5-HT was applied alone or co-applied with amitriptyline in cultured NCB-20 neuroblastoma cells known to express 5-HT3 receptors. To elucidate the mechanism of amitriptyline, we simulated the 5-HT3 receptor currents using Berkeley Madonna® software and calculated the rate constants of the agonist binding and receptor transition steps. The 5-HT3 receptor currents were inhibited by amitriptyline in a concentration-dependent, voltage-independent manner, and a competitive mode. Amitriptyline accelerated the desensitization of the 5-HT3 receptor. When amitriptyline was applied before 5-HT treatment, the currents rose slowly until the end of 5-HT treatment. When amitriptyline was co-applied with 5-HT, currents rose and decayed rapidly. Peak current amplitudes were decreased in both applications. All macroscopic currents recorded in whole cell voltage clamping experiments were reproduced by simulation and the changes of rate constants by amitriptyline were correlated with macroscopic current recording data. These results suggest that amitriptyline blocks the 5-HT3 receptor by close and open state blocking mechanisms, in a competitive manner. We could expand an understanding of pharmacological mechanisms of amitriptyline related to the modulation of a 5-HT3 receptor, a potential target of neurologic and psychiatric diseases through this study.
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Affiliation(s)
- Yong Soo Park
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Seok Ho Myeong
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - In-Beom Kim
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Ki-Wug Sung
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
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6
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Andersen ND, Nielsen BE, Corradi J, Tolosa MF, Feuerbach D, Arias HR, Bouzat C. Exploring the positive allosteric modulation of human α7 nicotinic receptors from a single-channel perspective. Neuropharmacology 2016; 107:189-200. [PMID: 26926428 DOI: 10.1016/j.neuropharm.2016.02.032] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/20/2016] [Accepted: 02/24/2016] [Indexed: 12/30/2022]
Abstract
Enhancement of α7 nicotinic receptor (nAChR) function by positive allosteric modulators (PAMs) is a promising therapeutic strategy to improve cognitive deficits. PAMs have been classified only on the basis of their macroscopic effects as type I, which only enhance agonist-induced currents, and type II, which also decrease desensitization and reactivate desensitized nAChRs. To decipher the molecular basis underlying these distinct activities, we explored the effects on single-α7 channel currents of representative members of each type and of less characterized compounds. Our results reveal that all PAMs enhance open-channel lifetime and produce episodes of successive openings, thus indicating that both types affect α7 kinetics. Different PAM types show different sensitivity to temperature, suggesting different mechanisms of potentiation. By using a mutant α7 receptor that is insensitive to the prototype type II PAM (PNU-120596), we show that some though not all type I PAMs share the structural determinants of potentiation. Overall, our study provides novel information on α7 potentiation, which is key to the ongoing development of therapeutic compounds.
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Affiliation(s)
- Natalia D Andersen
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - Beatriz E Nielsen
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - Jeremías Corradi
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - María F Tolosa
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - Dominik Feuerbach
- Neuroscience Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA 95757, USA
| | - Cecilia Bouzat
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina.
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7
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Arias HR, Ortells MO, Feuerbach D. (-)-Reboxetine inhibits muscle nicotinic acetylcholine receptors by interacting with luminal and non-luminal sites. Neurochem Int 2013; 63:423-31. [PMID: 23917086 DOI: 10.1016/j.neuint.2013.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/23/2013] [Accepted: 07/25/2013] [Indexed: 11/27/2022]
Abstract
The interaction of (-)-reboxetine, a non-tricyclic norepinephrine selective reuptake inhibitor, with muscle-type nicotinic acetylcholine receptors (AChRs) in different conformational states was studied by functional and structural approaches. The results established that (-)-reboxetine: (a) inhibits (±)-epibatidine-induced Ca(2+) influx in human (h) muscle embryonic (hα1β1γδ) and adult (hα1β1εδ) AChRs in a non-competitive manner and with potencies IC50=3.86±0.49 and 1.92±0.48 μM, respectively, (b) binds to the [(3)H]TCP site with ~13-fold higher affinity when the Torpedo AChR is in the desensitized state compared to the resting state, (c) enhances [(3)H]cytisine binding to the resting but activatableTorpedo AChR but not to the desensitized AChR, suggesting desensitizing properties, (d) overlaps the PCP luminal site located between rings 6' and 13' in the Torpedo but not human muscle AChRs. In silico mutation results indicate that ring 9' is the minimum structural component for (-)-reboxetine binding, and (e) interacts to non-luminal sites located within the transmembrane segments from the Torpedo AChR γ subunit, and at the α1/ε transmembrane interface from the adult muscle AChR. In conclusion, (-)-reboxetine non-competitively inhibits muscle AChRs by binding to the TCP luminal site and by inducing receptor desensitization (maybe by interacting with non-luminal sites), a mechanism that is shared by tricyclic antidepressants.
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Affiliation(s)
- Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA, USA.
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8
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Arias HR, Fedorov NB, Benson LC, Lippiello PM, Gatto GJ, Feuerbach D, Ortells MO. Functional and structural interaction of (-)-reboxetine with the human α4β2 nicotinic acetylcholine receptor. J Pharmacol Exp Ther 2012; 344:113-23. [PMID: 23010362 DOI: 10.1124/jpet.112.197905] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The interaction of the selective norepinephrine reuptake inhibitor (-)-reboxetine with the human α4β2 nicotinic acetylcholine receptor (nAChR) in different conformational states was studied by several functional and structural approaches. Patch-clamp and Ca(2+)-influx results indicate that (-)-reboxetine does not activate hα4β2 nAChRs via interaction with the orthosteric sites, but inhibits agonist-induced hα4β2 activation by a noncompetitive mechanism. Consistently, the results from the electrophysiology-based functional approach suggest that (-)-reboxetine may act via open channel block; therefore, it is capable of producing a use-dependent type of inhibition of the hα4β2 nAChR function. We tested whether (-)-reboxetine binds to the luminal [(3)H]imipramine site. The results indicate that, although (-)-reboxetine binds with low affinity to this site, it discriminates between the resting and desensitized hα4β2 nAChR ion channels. Patch-clamp results also indicate that (-)-reboxetine progressively inhibits the hα4β2 nAChR with two-fold higher potency at the end of one-second application of agonist, compared with the peak current. The molecular docking studies show that (-)-reboxetine blocks the ion channel at the level of the imipramine locus, between M2 rings 6' and 14'. In addition, we found a (-)-reboxetine conformer that docks in the helix bundle of the α4 subunit, near the middle region. According to molecular dynamics simulations, (-)-reboxetine binding is stable for both sites, albeit less stable than imipramine. The interaction of these drugs with the helix bundle might alter allostericaly the functionality of the channel. In conclusion, the clinical action of (-)-reboxetine may be produced (at least partially) by its inhibitory action on hα4β2 nAChRs.
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Affiliation(s)
- Hugo R Arias
- Department of Medical Education, College of Medicine, California Northstate University, Elk Grove, California, USA
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9
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Akdemir A, Rucktooa P, Jongejan A, Elk RV, Bertrand S, Sixma TK, Bertrand D, Smit AB, Leurs R, de Graaf C, de Esch IJ. Acetylcholine binding protein (AChBP) as template for hierarchical in silico screening procedures to identify structurally novel ligands for the nicotinic receptors. Bioorg Med Chem 2011; 19:6107-19. [DOI: 10.1016/j.bmc.2011.08.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 08/10/2011] [Accepted: 08/12/2011] [Indexed: 12/22/2022]
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10
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Davies PA. Allosteric modulation of the 5-HT(3) receptor. Curr Opin Pharmacol 2011; 11:75-80. [PMID: 21342788 DOI: 10.1016/j.coph.2011.01.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 01/26/2011] [Accepted: 01/31/2011] [Indexed: 11/29/2022]
Abstract
5-Hydroxytryptamine type 3 (5-HT(3)) receptors are ligand-gated ion channels that play important roles in depression, anxiety, substance abuse, emesis, inflammatory pain, spinal nociception, gastrointestinal function, and cardiovascular reflexes. Probably the most studied modulators of 5-HT(3) receptors are the high affinity competitive 'setron' antagonists typified by ondansetron. However, there exists a broad range of compounds that modulate the 5-HT(3) receptor, not through the orthosteric site but by binding to allosteric sites. Most notable are therapeutic compounds ascribed to certain targets but that allosterically modulate 5-HT(3) receptors at clinically relevant concentrations.
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Affiliation(s)
- Paul A Davies
- Department of Neuroscience, Tufts University, 136 Harrison Ave, Boston, MA 02111, USA.
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11
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Arias HR, Feuerbach D, Targowska-Duda KM, Russell M, Jozwiak K. Interaction of selective serotonin reuptake inhibitors with neuronal nicotinic acetylcholine receptors. Biochemistry 2010; 49:5734-42. [PMID: 20527991 DOI: 10.1021/bi100536t] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We compared the interaction of fluoxetine and paroxetine, two selective serotonin reuptake inhibitors (SSRIs), with the human (h) alpha4beta2, alpha3beta4, and alpha7 nicotinic acetylcholine receptors (AChRs) in different conformational states, using Ca(2+) influx, radioligand binding, and molecular docking approaches. The results established that (1) fluoxetine was more potent than paroxetine in inhibiting agonist-activated Ca(2+) influx on halpha4beta2 and halpha7 AChRs, whereas the potency of both SSRIs was practically the same in the halpha3beta4 AChR. [corrected] (2) SSRIs bind to the [(3)H]imipramine locus with a [corrected] higher affinity when the AChRs are in the desensitized states compared to the resting states. (3) The different receptor specificity for fluoxetine determined by their inhibitory potencies or binding affinities suggests different modes of interaction when the AChR is in the closed or activated state. (4) Neutral and protonated fluoxetine interacts with a binding domain located in the middle of the AChR ion channel. In conclusion, SSRIs inhibit the most important neuronal AChRs with potencies and affinities that are clinically relevant by binding to a luminal site that is shared with tricyclic antidepressants.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, Glendale, Arizona 85308, USA.
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12
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Walstab J, Rappold G, Niesler B. 5-HT(3) receptors: role in disease and target of drugs. Pharmacol Ther 2010; 128:146-69. [PMID: 20621123 DOI: 10.1016/j.pharmthera.2010.07.001] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 06/21/2010] [Indexed: 12/19/2022]
Abstract
Serotonin type 3 (5-HT(3)) receptors are pentameric ion channels belonging to the superfamily of Cys-loop receptors. Receptor activation either leads to fast excitatory responses or modulation of neurotransmitter release depending on their neuronal localisation. 5-HT(3) receptors are known to be expressed in the central nervous system in regions involved in the vomiting reflex, processing of pain, the reward system, cognition and anxiety control. In the periphery they are present on a variety of neurons and immune cells. 5-HT(3) receptors are known to be involved in emesis, pain disorders, drug addiction, psychiatric and GI disorders. Progress in molecular genetics gives direction to personalised medical strategies for treating complex diseases such as psychiatric and functional GI disorders and unravelling individual drug responses in pharmacogenetic approaches. Here we discuss the molecular basis of 5-HT(3) receptor diversity at the DNA and protein level, of which our knowledge has greatly extended in the last decade. We also evaluate their role in health and disease and describe specific case-control studies addressing the involvement of polymorphisms of 5-HT3 subunit genes in complex disorders and responses to drugs. Furthermore, we focus on the actual state of the pharmacological knowledge concerning not only classical 5-HT(3) antagonists--the setrons--but also compounds of various substance classes targeting 5-HT(3) receptors such as anaesthetics, opioids, cannabinoids, steroids, antidepressants and antipsychotics as well as natural compounds derived from plants. This shall point to alternative treatment options modulating the 5-HT(3) receptor system and open new possibilities for drug development in the future.
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Affiliation(s)
- Jutta Walstab
- Department of Human Molecular Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
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13
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Arias HR, Rosenberg A, Targowska-Duda KM, Feuerbach D, Jozwiak K, Moaddel R, Wainer IW. Tricyclic antidepressants and mecamylamine bind to different sites in the human alpha4beta2 nicotinic receptor ion channel. Int J Biochem Cell Biol 2010; 42:1007-18. [PMID: 20223294 DOI: 10.1016/j.biocel.2010.03.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 02/18/2010] [Accepted: 03/01/2010] [Indexed: 10/19/2022]
Abstract
The interaction of tricyclic antidepressants with the human (h) alpha4beta2 nicotinic acetylcholine receptor in different conformational states was compared with that for the noncompetitive antagonist mecamylamine by using functional and structural approaches. The results established that: (a) [(3)H]imipramine binds to halpha4beta2 receptors with relatively high affinity (K(d)=0.83+/-0.08 microM), but imipramine does not differentiate between the desensitized and resting states, (b) although tricyclic antidepressants inhibit (+/-)-epibatidine-induced Ca(2+) influx in HEK293-halpha4beta2 cells with potencies that are in the same concentration range as that for (+/-)-mecamylamine, tricyclic antidepressants inhibit [(3)H]imipramine binding to halpha4beta2 receptors with affinities >100-fold higher than that for (+/-)-mecamylamine. This can be explained by our docking results where imipramine interacts with the leucine (position 9') and valine (position 13') rings by van der Waals contacts, whereas mecamylamine interacts electrostatically with the outer ring (position 20'), (c) van der Waals interactions are in agreement with the thermodynamic results, indicating that imipramine interacts with the desensitized and resting receptors by a combination of enthalpic and entropic components. However, the entropic component is more important in the desensitized state, suggesting local conformational changes. In conclusion, our data indicate that tricyclic antidepressants and mecamylamine efficiently inhibit the ion channel by interacting at different luminal sites. The high proportion of protonated mecamylamine calculated at physiological pH suggests that this drug can be attracted to the channel mouth before binding deeper within the receptor ion channel finally blocking ion flux.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, 19555 N 59th Avenue, Glendale, AZ 85308, USA.
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14
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Arias HR, Targowska-Duda KM, Feuerbach D, Sullivan CJ, Maciejewski R, Jozwiak K. Different interaction between tricyclic antidepressants and mecamylamine with the human alpha3beta4 nicotinic acetylcholine receptor ion channel. Neurochem Int 2010; 56:642-9. [PMID: 20117161 DOI: 10.1016/j.neuint.2010.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 01/21/2010] [Accepted: 01/22/2010] [Indexed: 11/29/2022]
Abstract
The interaction of tricyclic antidepressants (TCAs) with the human (h)alpha3beta4 nicotinic acetylcholine receptor (AChR) in different conformational states was compared with that for mecamylamine by using functional and structural approaches including, Ca(2+) influx, radioligand binding, and molecular docking. The results established that: (a) [(3)H]imipramine binds to a single site with relatively high affinity (K(d) = 0.41 +/- 0.04 microM), (b) imipramine inhibits [(3)H]imipramine binding to the resting/kappa-bungarotoxin-bound AChR (K(i) = 0.68 +/- 0.08 microM) with practically the same affinity as to the desensitized/epibatidine-bound AChR (K(i) = 0.83 +/- 0.08 microM), suggesting that TCAs do not discriminate between these conformational states, and (c) although TCAs (IC(50) approximately 1.8-2.7 microM) and mecamylamine (IC(50) = 3.3 +/- 0.4 microM) inhibit (+/-)-epibatidine-induced Ca(2+) influx with potencies in the same concentration range, TCAs (K(i) approximately 1-3.6 microM), but not mecamylamine (apparent IC(50) approximately 0.2 mM), inhibit [(3)H]imipramine binding to halpha3beta4 AChRs in different conformational states. This is explained by our docking results where imipramine, in the neutral and protonated states, interacts with the leucine (position 9') and valine/phenylalanine (position 13') rings, whereas protonated mecamylamine (>99% at physiological pH) interacts with the outer ring (position 20'). Our data indicate that TCAs bind to overlapping sites located between the serine and valine/phenylalanine rings in the halpha3beta4 AChR ion channel, whereas protonated mecamylamine can be attracted to the channel mouth before blocking ion flux by interacting with a luminal site in its neutral state.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, Glendale, AZ 85308, USA.
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15
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Corradi J, Gumilar F, Bouzat C. Single-channel kinetic analysis for activation and desensitization of homomeric 5-HT(3)A receptors. Biophys J 2009; 97:1335-45. [PMID: 19720021 DOI: 10.1016/j.bpj.2009.06.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 06/10/2009] [Accepted: 06/15/2009] [Indexed: 10/25/2022] Open
Abstract
The 5-HT(3)A receptor is a member of the Cys-loop family of ligand-gated ion channels. To perform kinetic analysis, we mutated the 5-HT3A subunit to obtain a high-conductance form so that single-channel currents can be detected. At all 5-HT concentrations (> 0.1 microM), channel activity appears as openings in quick succession that form bursts, which coalesce into clusters. By combining single-channel and macroscopic data, we generated a kinetic model that perfectly describes activation, deactivation, and desensitization. The model shows that full activation arises from receptors with three molecules of agonist bound. It reveals an earlier conformational change of the fully liganded receptor that occurs while the channel is still closed. From this pre-open closed state, the receptor enters into an open-closed cycle involving three open states, which form the cluster whose duration parallels the time constant of desensitization. A similar model lacking the pre-open closed state can describe the data only if the opening rates are fixed to account for the slow activation rate. The application of the model to M4 mutant receptors shows that position 10' contributes to channel opening and closing rates. Thus, our kinetic model provides a foundation for understanding structural bases of activation and drug action.
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Affiliation(s)
- Jeremías Corradi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur/Consejo Nacional de Investigaciones Científicas y Técnicas, Bahía Blanca, Argentina
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Arias HR, Gumilar F, Rosenberg A, Targowska-Duda KM, Feuerbach D, Jozwiak K, Moaddel R, Wainer IW, Bouzat C. Interaction of bupropion with muscle-type nicotinic acetylcholine receptors in different conformational states. Biochemistry 2009; 48:4506-18. [PMID: 19334677 DOI: 10.1021/bi802206k] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To characterize the binding sites and the mechanisms of inhibition of bupropion on muscle-type nicotinic acetylcholine receptors (AChRs), structural and functional approaches were used. The results established that bupropion (a) inhibits epibatidine-induced Ca(2+) influx in embryonic muscle AChRs, (b) inhibits adult muscle AChR macroscopic currents in the resting/activatable state with approximately 100-fold higher potency compared to that in the open state, (c) increases the desensitization rate of adult muscle AChRs from the open state and impairs channel opening from the resting state, (d) inhibits binding of [(3)H]TCP and [(3)H]imipramine to the desensitized/carbamylcholine-bound Torpedo AChR with higher affinity compared to the resting/alpha-bungarotoxin-bound AChR, (e) binds to the Torpedo AChR in either state mainly by an entropy-driven process, and (f) interacts with a binding domain located between the serine (position 6') and valine (position 13') rings, by a network of van der Waals, hydrogen bond, and polar interactions. Collectively, our data indicate that bupropion first binds to the resting AChR, decreasing the probability of ion channel opening. The remnant fraction of open ion channels is subsequently decreased by accelerating the desensitization process. Bupropion interacts with a luminal binding domain shared with PCP that is located between the serine and valine rings, and this interaction is mediated mainly by an entropy-driven process.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, Glendale, Arizona 85308, USA.
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Arias HR. Is the inhibition of nicotinic acetylcholine receptors by bupropion involved in its clinical actions? Int J Biochem Cell Biol 2009; 41:2098-108. [PMID: 19497387 DOI: 10.1016/j.biocel.2009.05.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 05/23/2009] [Accepted: 05/26/2009] [Indexed: 11/26/2022]
Abstract
In this mini review we will focus on those molecular and cellular mechanisms exerted by bupropion (BP), ultimately leading to the antidepressant and anti-nicotinic properties described for this molecule. The main pharmacological mechanism is based on the fact that BP induces the release as well as inhibits the reuptake of neurotransmitters such as a dopamine (DA) and norepinephrine (NE). Additional mechanisms of action have been also determined. For example, BP is a noncompetitive antagonist (NCA) of several nicotinic acetylcholine receptors (AChRs). Based on this evidence, the dual antidepressant and anti-nicotinic activity of BP is currently considered to be mediated by its stimulatory action on the DA and NE systems as well as its inhibitory action on AChRs. Considering the results obtained in the archetypical mouse muscle AChR, a sequential mechanism can be hypothesized to explain the inhibitory action of BP on neuronal AChRs: (1) BP first binds to AChRs in the resting state, decreasing the probability of ion channel opening, (2) the remnant fraction of open ion channels is subsequently decreased by accelerating the desensitization process, and (3), BP interacts with a binding domain located between the serine (position 6') and valine (position 13') rings that is shared with the NCA phencyclidine and other tricyclic antidepressants. This new evidence paves the way for further investigations using AChRs as targets for the action of safer antidepressants and novel anti-addictive compounds.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, 19555 N. 59th Avenue, Glendale, AZ 85308, USA.
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Ulens C, Akdemir A, Jongejan A, van Elk R, Bertrand S, Perrakis A, Leurs R, Smit AB, Sixma TK, Bertrand D, de Esch IJP. Use of Acetylcholine Binding Protein in the Search for Novel α7 Nicotinic Receptor Ligands. In Silico Docking, Pharmacological Screening, and X-ray Analysis. J Med Chem 2009; 52:2372-83. [DOI: 10.1021/jm801400g] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chris Ulens
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Atilla Akdemir
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Aldo Jongejan
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Rene van Elk
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Sonia Bertrand
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Anastassis Perrakis
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Rob Leurs
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - August B. Smit
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Titia K. Sixma
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Daniel Bertrand
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
| | - Iwan J. P. de Esch
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Amsterdam, The Netherlands, Leiden/Amsterdam Center for Drug Research (LACDR), Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands, Department of Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands, and Department of Neuroscience, Centre Medical Universitaire, Geneva, Switzerland
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Arias HR, Santamaría A, Ali SF. Pharmacological and neurotoxicological actions mediated by bupropion and diethylpropion. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 88:223-55. [PMID: 19897080 DOI: 10.1016/s0074-7742(09)88009-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The antiappetite agent diethylpropion (DEP), and the antidepressant and antismoking aid compound bupropion (BP), not only share the same structural motif but also present similar mechanisms of action in the CNS. For example, both drugs induce the release as well as inhibit the reuptake of neurotransmitters such as a dopamine (DA) and norepinephrine (NE). In general, they produce mild side effects, including reversible psychomotor alterations mostly in geriatric patients (by BP), or moderate changes in neurotransmitter contents linked to oxidative damage (by DEP). Therefore, attention must be paid during any therapeutic use of these agents. Regarding the interaction of BP with the DA transporter, residues S359, located in the middle of TM7, and A279, located close to the extracellular end of TM5, contribute to the binding and blockade of translocation mediated by BP, respectively. Additional mechanisms of action have also been determined for each compound. For example, BP is a noncompetitive antagonist (NCA) of several nicotinic acetylcholine receptors (AChRs). Based on this evidence, the dual antidepressant and antinicotinic activity of BP is currently considered to be mediated by its stimulatory action on DA and NE systems as well as its inhibitory action on AChRs. Considering the results obtained in the archetypical mouse muscle AChR, a sequential mechanism can be hypothesized to explain the inhibitory action of BP on neuronal AChRs: (1) BP first binds to AChRs in the resting state, decreasing the probability of ion channel opening, (2) the remnant fraction of open ion channels is subsequently decreased by accelerating the desensitization process, and finally (3) BP interacts with a binding domain located between the serine (position 9') and valine (position 13') rings that is shared with the NCA phencyclidine and other tricyclic antidepressants. The homologous location in the alpha3beta4 AChR is between the serine and valine/phenylalanine rings. This new evidence opens a window for further investigation using AChRs as targets for the action of safer antidepressants and novel antiaddictive compounds.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, Glendale, Arizona 85308, USA
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The interface between extracellular and transmembrane domains of homomeric Cys-loop receptors governs open-channel lifetime and rate of desensitization. J Neurosci 2008; 28:7808-19. [PMID: 18667613 DOI: 10.1523/jneurosci.0448-08.2008] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The lifetimes of activated postsynaptic receptor channels contribute to the efficiency of synaptic transmission. Here we show that structural differences within the interface dividing extracellular and transmembrane domains of homomeric alpha7 and 5-HT(3A) receptors account for the large differences in open-channel lifetime and time of desensitization onset between these contrasting members of the Cys-loop receptor superfamily. For alpha7 receptors, agonist-evoked single-channel currents appear mainly as isolated brief openings (tau(o) = 0.35 ms), whereas macroscopic currents after a step pulse of agonist desensitize rapidly (tau(d) = 0.4 ms). In contrast for 5-HT(3A) receptors, agonist-evoked single-channel currents appear as clusters of many long openings in quick succession (tau(cluster) = 1.2 s), whereas macroscopic currents desensitize slowly (tau(d) = 1.1 s). A chimeric alpha7-5HT(3A) receptor exhibits functional properties intermediate between those of the parent receptors, but the functional signatures of each parent are reconstituted after substituting the major loops within the interface of the extracellular and transmembrane domains from the corresponding parent receptor. Furthermore, these structural loops contribute to open-channel lifetime and time of desensitization onset in a nonadditive manner. The results suggest that desensitization is the major determinant of the lifetimes of activated alpha7 and 5-HT(3A) receptors and that functional differences between the two receptors arise primarily through structural differences at the interface between extracellular and transmembrane domains.
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