1
|
Horackova H, Vachalova V, Abad C, Karahoda R, Staud F. Perfused rat term placenta as a preclinical model to investigate placental dopamine and norepinephrine transport. Clin Sci (Lond) 2023; 137:149-161. [PMID: 36598165 DOI: 10.1042/cs20220726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/22/2022] [Accepted: 01/04/2023] [Indexed: 01/05/2023]
Abstract
The placenta represents a non-neuronal organ capable of transporting and metabolizing monoamines. Since these bioactive molecules participate in numerous processes essential for placental and fetal physiology, any imbalance in their levels during pregnancy may affect brain development, projecting a higher risk of behavioral disorders in childhood or adulthood. Notably, the monoamine system in the placenta is a target of various psychoactive drugs and can be disrupted in several pregnancy pathologies. As research in pregnant women poses significant ethical restrictions, animal models are widely employed to study monoamine homeostasis as a mechanism involved in fetal programming. However, detailed knowledge of monoamine transport in the rat placenta is still lacking. Moreover, relatability to the human placental monoamine system is not examined. The present study provides insights into the transplacental monoamine dynamics between maternal and fetal circulation. We show that norepinephrine maternal-to-fetal transport is <4% due to high metabolism within the trophoblast. In contrast, dopamine maternal-to-fetal transport exceeds 25%, likely through passive transport across the membrane. In addition, we show high clearance of norepinephrine and dopamine from the fetal circulation mediated by the organic cation transporter 3 (OCT3). Altogether, we present transcriptional and functional evidence that the in situ rat placenta perfusion represents a suitable model for (patho)physiological investigation of dopamine and norepinephrine homeostasis in the fetoplacental unit. With the rapid advancements in drug discovery and environmental toxicity, the use of rat placenta as a preclinical model could facilitate screening of possible xenobiotic effects on monoamine homeostasis in the placenta.
Collapse
Affiliation(s)
- Hana Horackova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic
| | - Veronika Vachalova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic
| | - Cilia Abad
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic
| | - Rona Karahoda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic
| | - Frantisek Staud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic
| |
Collapse
|
2
|
Vachalova V, Karahoda R, Ottaviani M, Anandam KY, Abad C, Albrecht C, Staud F. Functional reorganization of monoamine transport systems during villous trophoblast differentiation: evidence of distinct differences between primary human trophoblasts and BeWo cells. Reprod Biol Endocrinol 2022; 20:112. [PMID: 35927731 PMCID: PMC9351077 DOI: 10.1186/s12958-022-00981-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/19/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Three primary monoamines-serotonin, norepinephrine, and dopamine-play major roles in the placenta-fetal brain axis. Analogously to the brain, the placenta has transport mechanisms that actively take up these monoamines into trophoblast cells. These transporters are known to play important roles in the differentiated syncytiotrophoblast layer, but their status and activities in the undifferentiated, progenitor cytotrophoblast cells are not well understood. Thus, we have explored the cellular handling and regulation of monoamine transporters during the phenotypic transitioning of cytotrophoblasts along the villous pathway. METHODS Experiments were conducted with two cellular models of syncytium development: primary trophoblast cells isolated from the human term placenta (PHT), and the choriocarcinoma-derived BeWo cell line. The gene and protein expression of membrane transporters for serotonin (SERT), norepinephrine (NET), dopamine (DAT), and organic cation transporter 3 (OCT3) was determined by quantitative PCR and Western blot analysis, respectively. Subsequently, the effect of trophoblast differentiation on transporter activity was analyzed by monoamine uptake into cells. RESULTS We present multiple lines of evidence of changes in the transcriptional and functional regulation of monoamine transporters associated with trophoblast differentiation. These include enhancement of SERT and DAT gene and protein expression in BeWo cells. On the other hand, in PHT cells we report negative modulation of SERT, NET, and OCT3 protein expression. We show that OCT3 is the dominant monoamine transporter in PHT cells, and its main functional impact is on serotonin uptake, while passive transport strongly contributes to norepinephrine and dopamine uptake. Further, we show that a wide range of selective serotonin reuptake inhibitors affect serotonin cellular accumulation, at pharmacologically relevant drug concentrations, via their action on both OCT3 and SERT. Finally, we demonstrate that BeWo cells do not well reflect the molecular mechanisms and properties of healthy human trophoblast cells. CONCLUSIONS Collectively, our findings provide insights into the regulation of monoamine transport during trophoblast differentiation and present important considerations regarding appropriate in vitro models for studying monoamine regulation in the placenta.
Collapse
Affiliation(s)
- Veronika Vachalova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Rona Karahoda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Martina Ottaviani
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Kasin Yadunandam Anandam
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Cilia Abad
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
| | - Frantisek Staud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic.
| |
Collapse
|
3
|
Functional characterization of dopamine and norepinephrine transport across the apical and basal plasma membranes of the human placental syncytiotrophoblast. Sci Rep 2022; 12:11603. [PMID: 35804076 PMCID: PMC9270497 DOI: 10.1038/s41598-022-15790-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/29/2022] [Indexed: 11/23/2022] Open
Abstract
The human placenta represents a unique non-neuronal site of monoamine transporter expression, with pathophysiological relevance during the prenatal period. Monoamines (serotonin, dopamine, norepinephrine) are crucial neuromodulators for proper placenta functions and fetal development, including cell proliferation, differentiation, and neuronal migration. Accumulating evidence suggests that even a transient disruption of monoamine balance during gestation may lead to permanent changes in the fetal brain structures and functions, projecting into adulthood. Nonetheless, little is known about the transfer of dopamine and norepinephrine across the placental syncytiotrophoblast. Employing the method of isolated membranes from the human term placenta, here we delineate the transport mechanisms involved in dopamine and norepinephrine passage across the apical microvillous (MVM) and basal membranes. We show that the placental uptake of dopamine and norepinephrine across the mother-facing MVM is mediated via the high-affinity and low-capacity serotonin (SERT/SLC6A4) and norepinephrine (NET/SLC6A2) transporters. In the fetus-facing basal membrane, however, the placental uptake of both monoamines is controlled by the organic cation transporter 3 (OCT3/SLC22A3). Our findings thus provide insights into physiological aspects of dopamine and norepinephrine transport across both the maternal and fetal sides of the placenta. As monoamine transporters represent targets for several neuroactive drugs such as antidepressants, our findings are pharmacologically relevant to ensure the safety of drug use during pregnancy.
Collapse
|
4
|
Pharmacological characterization and anatomical distribution of the dopamine transporter in the mouse cerebellum. THE CEREBELLUM 2009; 7:242-51. [PMID: 18418665 DOI: 10.1007/s12311-008-0005-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We studied the binding parameters, the pharmacological profile and the anatomical distribution of the dopamine transporter in the mouse cerebellum by using the specific dopamine uptake antagonist [(3)H]GBR12935 and an antidopamine transporter monoclonal antibody. Competition experiments in cerebellar and striatal membrane preparations showed that [(3)H]GBR12935 binds to a specific binding site, sensitive to dopamine and low concentrations of mazindol. The affinity of dopamine for the cerebellar binding site was one order of magnitude lower than the affinity for the striatal binding site. Saturation experiments in cerebellar membrane preparations and thin frozen sections showed that the affinity of [(3)H]GBR12935 for this binding site is similar to its affinity for the striatal dopamine transporter. Saturable binding was lobule specific and in general was higher in the molecular layer compared to the granule cell layer. The immunohistochemical signal was mostly concentrated in the Purkinje cell layer and the cerebellar nuclei. The results suggest that the cerebellar dopamine transporter is similar but not identical to the striatal dopamine transporter and that it is present in the mouse cerebellum in a lobule and lamina specific pattern.
Collapse
|
5
|
Mcgeehan AJ, Janak PH, Olive MF. Effect of the mGluR5 antagonist 6-methyl-2-(phenylethynyl)pyridine (MPEP) on the acute locomotor stimulant properties of cocaine, D-amphetamine, and the dopamine reuptake inhibitor GBR12909 in mice. Psychopharmacology (Berl) 2004; 174:266-73. [PMID: 14726993 DOI: 10.1007/s00213-003-1733-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
RATIONALE Recent evidence suggests that, in addition to ascending monoaminergic systems, glutamate systems also play a role in psychostimulant-induced locomotor activity. The present study was conducted to examine the effects of the selective type-5 metabotropic glutamate receptor (mGluR5) antagonist 6-methyl-2-(phenylethynyl)pyridine (MPEP) on the acute locomotor stimulant effects of cocaine, D-amphetamine, and the dopamine reuptake inhibitor GBR12909. METHODS Male DBA/2J mice were treated with saline or MPEP (1, 5, 20 or 30 mg/kg i.p.) 10 min prior to the administration of cocaine (15 mg/kg or 30 mg/kg i.p.), D-amphetamine (3 mg/kg or 5 mg/kg i.p.) or GBR12909 (10 mg/kg or 20 mg/kg i.p.). Locomotor activity was then monitored in an open-field environment for 30 min. The effects of MPEP alone (1, 5, 20 and 30 mg/kg i.p.) on locomotor activity were also examined. RESULTS MPEP dose dependently inhibited the acute locomotor stimulant effects of cocaine, D-amphetamine, and the 10-mg/kg dose of GBR12909. However, MPEP had no effect on the locomotor stimulant effects of the higher (20 mg/kg) dose of GBR12909. When tested alone, MPEP increased locomotor activity at doses of 5 mg/kg and 20 mg/kg. CONCLUSIONS Our data suggest that mGluR5 receptors not only mediate spontaneous locomotor activity in DBA/2J mice but also the acute locomotor stimulant effects of cocaine, D-amphetamine and lower doses of GBR12909. However, the fact that MPEP did not attenuate the locomotor stimulant effects of the high (20 mg/kg) dose of GBR12909 suggests complex interactions between metabotropic glutamate receptors, dopamine transporters and possibly other monoamines in the regulation of psychostimulant-induced locomotor activity.
Collapse
Affiliation(s)
- Andrew J Mcgeehan
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California at San Francisco, 5858 Horton Street, Suite 200, Emeryville, CA 94608, USA
| | | | | |
Collapse
|
6
|
Zhu J, Crooks PA, Ayers JT, Sumithran SP, Dwoskin LP. N-n-alkylnicotinium andN-n-alkylpyridinium analogs inhibit the dopamine transporter: Selectivity as nicotinic receptor antagonists. Drug Dev Res 2003. [DOI: 10.1002/ddr.10328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
7
|
Thümen A, Qadri F, Sarkar R, Moser A. GBR-12909 effect on dopamine outflow depends on phosphorylation in the caudate nucleus of the rat. Synapse 2002; 46:72-8. [PMID: 12211084 DOI: 10.1002/syn.10124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Modulation of the dopamine (DA) transporter inhibitor GBR-12909 effect on DA release by protein kinases and protein phosphatases was studied in slices of the rat caudate nucleus measuring DA outflow in the superfusate of static chambers. Activation of protein kinase A and C markedly enhanced the effect of GBR-12909, whereas protein kinase inhibition by H7 reduced the GBR-12909 effect. Inhibition of protein phosphatases (PPP) 1 and 2A by okadaic acid did not modify basal outflow of DA. However, after the addition of okadaic acid a dramatic and biphasic effect was found when DA outflow was enhanced by GBR-12909. Inhibition of PPP 2A enhanced extracellular DA levels, while inhibition of PPP 1 and 2A completely abolished the effect of GBR-12909. In contrast to tetrodotoxin, the voltage-activated calcium channel blocker omega-conotoxin MVIIC inhibited GBR-12909 effects on DA outflow. Additionally, in aCSF devoid of calcium GBR-12909 did not increase DA liberation. These results suggest a complex and strong influence of phosphorylation on GBR-12909 effects on calcium channel-dependent DA outflow at low-affinity piperazine binding sites in slices of the rat caudate nucleus in vitro.
Collapse
Affiliation(s)
- A Thümen
- Neurochemical Research Group, Department of Neurology, Medical University of Lübeck, Lübeck, Germany.
| | | | | | | |
Collapse
|
8
|
Abstract
Substance P receptor [neurokinin 1 (NK1] antagonists (SPAs) represent a novel mechanistic approach to antidepressant therapy with comparable clinical efficacy to selective serotonin reuptake inhibitors (SSRIs). Because SSRIs are thought to exert their therapeutic effects by enhancing central serotonergic function, we have examined whether SPAs regulate neuronal activity in the dorsal raphe nucleus (DRN), the main source of serotonergic projections to the forebrain. Using in vivo electrophysiological techniques in the guinea pig, we found that administration of the highly selective NK1 receptor antagonist 1-(5-[[(2R,3S)-2-([(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethyl]oxy)-3-(4-phenyl)morpholin-4-yl]methyl]-2H-1,2,3-triazol-4-yl)-N,N-dimethylmethanamine (L-760735) caused an increase in DRN neuronal firing rate. However, unlike chronic treatment with fluoxetine, there was no detectable 5-HT1A autoreceptor desensitization. In vitro electrophysiological investigation showed that these effects were not mediated by a direct action in the DRN, an observation supported by immunocytochemical analysis that identified the lateral habenula (LHb) as a more likely site of action. Subsequently, we found that local application of L-760735 into the LHb increased firing in the DRN, which, together with our data showing that L-760735 increased metabolic activity in the cingulate cortex, amygdala, LHb, and DRN, indicates that the effects of L-760735 may be mediated by disinhibition of forebrain structures acting via a habenulo raphe projection. These findings support other evidence for an antidepressant profile of SPAs and suggest that regulation of DRN neuronal activity may contribute to their antidepressant mechanism of action but in a manner that is distinct from monoamine reuptake inhibitors.
Collapse
|
9
|
Maubach KA, Martin K, Chicchi G, Harrison T, Wheeldon A, Swain CJ, Cumberbatch MJ, Rupniak NMJ, Seabrook GR. Chronic substance P (NK1) receptor antagonist and conventional antidepressant treatment increases burst firing of monoamine neurones in the locus coeruleus. Neuroscience 2002; 109:609-17. [PMID: 11823070 DOI: 10.1016/s0306-4522(01)00467-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The mechanism of action of conventional antidepressants (e.g. imipramine) has been linked to modulation of central monoamine systems. Substance P (NK1) receptor antagonists may have antidepressant and anxiolytic effects in patients with major depressive disorder and high anxiety but, unlike conventional antidepressants, are independent of activity at monoamine reuptake sites, transporters, receptors, or monoamine oxidase. To investigate the possibility that substance P receptor antagonists influence central monoamine systems indirectly, we have compared the effects of chronic administration of imipramine with that of the substance P receptor antagonist L-760735 on the spontaneous firing activity of locus coeruleus neurones. Electrophysiological recordings were made from brain slices prepared from guinea-pigs that had been dosed orally every day for 4 weeks with either L-760735 (3 mg/kg), imipramine (10 mg/kg), or vehicle (water), or naive animals. Chronic, but not acute, treatment with the substance P receptor antagonist L-760735, induced burst firing of neurones in the locus coeruleus. This effect resembles that of the conventional antidepressant imipramine. However, their effects are dissociable since, in contrast to chronic imipramine treatment, chronic L-760735 treatment does not cause functional desensitisation of somatic alpha2 adrenoceptors. The mechanism by which chronic substance P receptor antagonist or conventional antidepressant treatment influences the pattern of firing activity of norepinephrine neurones remains to be elucidated. However, an indirect action in the periphery or distant brain nuclei has been excluded by the use of the in vitro slice preparation, suggesting a local site of action in the locus coeruleus.
Collapse
Affiliation(s)
- K A Maubach
- Department of Pharmacology, Merck Sharp & Dohme Neuroscience Research Centre, Essex CM20 2QR, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Izenwasser S, French D, Carroll FI, Kunko PM. Continuous infusion of selective dopamine uptake inhibitors or cocaine produces time-dependent changes in rat locomotor activity. Behav Brain Res 1999; 99:201-8. [PMID: 10512586 DOI: 10.1016/s0166-4328(98)00104-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chronic continuous cocaine treatment produces a unique pattern of locomotor activation over time. An initial, progressive increase in locomotion is indicative of sensitization. Unlike intermittent cocaine, this increase is subsequently reversed during the continuous exposure, and activity returns to pre-sensitization levels within days. To study the pharmacological mechanisms that underlie this phenomenon, osmotic minipumps containing cocaine or selective uptake inhibitors of dopamine (GBR 12909 or RTI-117), serotonin (fluoxetine), or norepinephrine (nisoxetine) were implanted into rats. Locomotor activity was measured for 1 h each day, beginning 4 h after pumps were implanted. In the cocaine group, activity was significantly elevated on the first day, peaked between the second and third days, then decreased to a plateau which remained significantly above control levels through 14 days. Peak activity in the GBR 12909 and RTI-117 animals occurred on the first day, followed by a significant decrease 24-48 h later, but not complete tolerance. Neither fluoxetine nor nisoxetine altered locomotor activity. The selective dopamine uptake inhibitors produced some of the effects of cocaine. The possibilities that cocaine interacts with the dopamine transporter in a qualitatively different manner from that of these selective dopamine uptake inhibitors, or that other monoamine systems are involved, are discussed.
Collapse
Affiliation(s)
- S Izenwasser
- Psychobiology Section, National Institute on Drug Abuse, Division of Intramural Research, National Institutes of Health, Baltimore, MD 21224, USA.
| | | | | | | |
Collapse
|
11
|
Kramer MS, Cutler N, Feighner J, Shrivastava R, Carman J, Sramek JJ, Reines SA, Liu G, Snavely D, Wyatt-Knowles E, Hale JJ, Mills SG, MacCoss M, Swain CJ, Harrison T, Hill RG, Hefti F, Scolnick EM, Cascieri MA, Chicchi GG, Sadowski S, Williams AR, Hewson L, Smith D, Carlson EJ, Hargreaves RJ, Rupniak NM. Distinct mechanism for antidepressant activity by blockade of central substance P receptors. Science 1998; 281:1640-5. [PMID: 9733503 DOI: 10.1126/science.281.5383.1640] [Citation(s) in RCA: 733] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The localization of substance P in brain regions that coordinate stress responses and receive convergent monoaminergic innervation suggested that substance P antagonists might have psychotherapeutic properties. Like clinically used antidepressant and anxiolytic drugs, substance P antagonists suppressed isolation-induced vocalizations in guinea pigs. In a placebo-controlled trial in patients with moderate to severe major depression, robust antidepressant effects of the substance P antagonist MK-869 were consistently observed. In preclinical studies, substance P antagonists did not interact with monoamine systems in the manner seen with established antidepressant drugs. These findings suggest that substance P may play an important role in psychiatric disorders.
Collapse
Affiliation(s)
- M S Kramer
- Merck Research Laboratories, West Point, PA 19456, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Abstract
The anxiolytic-like properties of dopamine agonists and antagonists with different receptor profiles were investigated in the ultrasonic vocalization test in rats after subcutaneous administration. Only dopamine D2 receptor agonists inhibited ultrasonic vocalization with the following ED50 values: apomorphine (0.07 mg/kg), quinelorane (0.01 mg/kg), quinpirole (0.04 mg/kg), pramipexole (0.09 mg/kg), roxindole (0.04 mg/kg), talipexole (0.04 mg/kg), (+/-)-7-OH-DPAT (0.05 mg/kg), (+/-)-PPHT (0.03 mg/kg), (-)-TNPA (0.06 mg/kg), PD128907 (0.13 mg/kg). The D2 antagonists haloperidol, mazapertine, raclopride, remoxipride, L745870, U99194A, U101958 and S(-)-DS121, the partial agonists PD143188 and preclamol, the selective D1 agonist R(+)-SKF38393 and the D1 antagonist SCH23390, and the uptake inhibitors GBR12909, GBR12935 and indatraline lacked significant inhibitory effects on ultrasonic vocalization. Because at least some of the D2 receptor agonists investigated have selectivity for dopamine autoreceptors, it is speculated that the dopamine autoreceptor may be a target for the development of new antianxiety drugs.
Collapse
Affiliation(s)
- G D Bartoszyk
- Merck KGaA, Department of CNS Research, Darmstadt, Germany.
| |
Collapse
|
13
|
Chen NH, Xu C, Coffey LL, Reith ME. [3H]WIN 35,428 [2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane] binding to rat brain membranes. Comparing dopamine cell body areas with nerve terminal regions. Biochem Pharmacol 1996; 51:563-6. [PMID: 8619903 DOI: 10.1016/0006-2952(95)02208-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Potential differences between somatodendritic acid and axonal dopamine transporters were examined by comparing the binding constants of [3H]WIN 35, 428 [2 beta-carbomethoxy- 3 beta-(4-fluorophenyl)tropane] binding to membranes prepared from the rat ventral mesencephalon, containing A9 and A10 dopamine cell bodies, and from the nucleus accumbens. Saturation analysis of [3H]WIN 35,428 binding, in the presence of compounds to occlude norepinephrine and serotonin transporters, was performed by both the "unlabeled" method (varying unlabeled ligand) and "labeled" method (varying radioligand). The density of binding was substantially lower in the ventral mesencephalon than in the nucleus accumbens, but the binding affinity was only slightly different. Likewise, the differences between the two regions in the inhibitory potency of cocaine and GBR 12909 [1-(2-di(4-fluorophenyl)-methoxy-ethyl)4-(3-phenylpropyl)piperazine] were not substantial. The results suggest that somatodendritic and axonal dopamine transporters in the ventral mesencephalon and nucleus accumbens are not very different as far as their binding domains for uptake blockers such as cocaine and GBR 12909 are concerned.
Collapse
Affiliation(s)
- N H Chen
- School of Basic Medical Sciences, Nanjing Medical University, People's Republic of China
| | | | | | | |
Collapse
|
14
|
Dutta AK, Xu C, Reith ME. Structure-activity relationship studies of novel 4-[2-[bis(4-fluorophenyl)methoxy]ethyl]-1-(3-phenylpropyl)piperidine analogs: synthesis and biological evaluation at the dopamine and serotonin transporter sites. J Med Chem 1996; 39:749-56. [PMID: 8576918 DOI: 10.1021/jm9506581] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several analogs of the potent dopamine (DA) transporter ligand 4-[2-[bis(4-fluorophenyl)-methoxy]ethyl]-1-(3-phenylpropyl)piperidine, 1b, were made and biologically evaluated for their binding at the DA and serotonin (5HT) transporters in rat striatal membranes. Different alkyl chain lengths and substitutions were introduced in these molecules to generate an optimum activity and selectivity for the DA transporter. In general, unsubstituted and fluoro-substituted compounds were the most active and selective for the DA transporter. The compound 4-[2-(diphenylmethoxy)ethyl]-1-benzylpiperidine, 9a, showed high potency and was the most selective for the DA transporter (5HT/DA = 49) in this series of compounds. Some of these novel analogs were found to be more selective in binding at the DA transporter than the original GBR 12909 molecule, 1-[2-]bis(4-fluorophenyl)methoxy]ethyl]-4-(3- phenylpropyl)piperidine.
Collapse
Affiliation(s)
- A K Dutta
- Organix Inc., Woburn, Massachusetts 01801, USA
| | | | | |
Collapse
|
15
|
Dersch CM, Akunne HC, Partilla JS, Char GU, de Costa BR, Rice KC, Carroll FI, Rothman RB. Studies of the biogenic amine transporters. 1. Dopamine reuptake blockers inhibit [3H]mazindol binding to the dopamine transporter by a competitive mechanism: preliminary evidence for different binding domains. Neurochem Res 1994; 19:201-8. [PMID: 8183430 DOI: 10.1007/bf00966817] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The present study addressed the hypothesis that the DA transporter ligand, [3H]mazindol, labels multiple sites/states associated with the dopamine (DA) transporter in striatal membranes. Incubations with [3H]mazindol proceeded for 18-24 hr at 4 degrees C in 55.2 mM sodium phosphate buffer, pH 7.4, with a protease inhibitor cocktail. In order to obtain data suitable for quantitative curve fitting, it was necessary to repurify the [3H]mazindol by HPLC before a series of experiments. Under these conditions, we observed greater than 80% specific binding. The method of binding surface analysis was used to characterize the interaction of GBR12935, BTCP, mazindol, and CFT with binding site/sites labeled by [3H]mazindol. A one site model fit the data as well as the two site model: Bmax = 16911 fmol/mg protein, Kd of [3H]mazindol = 75 nM, Ki of GBR12935 = 8.1 nM, Ki of CFT = 50 nM and Ki of BTCP = 44 nM. The inhibitory mechanism (competitive or noncompetitive) of several drugs (GBR12935, CFT, BTCP, cocaine, cis-flupentixol, nomifensine, WIN35,065-2, bupropion, PCP, and benztropine) was determined. All drugs inhibited [3H]mazindol binding by a competitive mechanism. Although the ligand-selectivity of the [3H]mazindol binding site indicates that it is the uptake inhibitor recognition site of the classic DA transporter, the quantitative differences among the ligand-selectivities of different radioligands for the same site suggest that each radioligand labels different overlapping domains of the DA uptake inhibitor recognition site. It is likely that development of domain-selective drugs may further our understanding of the DA transporter.
Collapse
Affiliation(s)
- C M Dersch
- Clinical Psychopharmacology Section, NIDA Addiction Research Center, NIH, Baltimore, Maryland 21224
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Wheeler DD, Edwards AM, Ondo JG. Dopamine uptake in five structures of the brain: comparison of rate, sodium dependence and sensitivity to cocaine. Neuropharmacology 1993; 32:501-8. [PMID: 8321431 DOI: 10.1016/0028-3908(93)90176-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The rate of uptake of dopamine (DA) per microgram protein and the sensitivity of uptake to sodium ([Na]o) and cocaine, have been measured in synaptosomes from five structures in the brain of the rat: striatum, nucleus accumbens, neocortex, limbic cortex and thalamus. Probably reflecting the number of DA terminals, there was a wide variation in the rate of uptake in the different structures: uptake was far greater in the striatum and nucleus accumbens (10-20-fold) than in the neocortex, limbic cortex or thalamus. Uptake in all structures was inhibited by cocaine. With high [Na]o, the IC50's varied from 1.10 microM for the thalamus to 3.32 microM for the nucleus accumbens. Maximum percentage inhibition varied from 76.0 for limbic cortex to 96.8 for nucleus accumbens and 97.7 for striatum; thus most uptake was carrier-mediated. With low [Na]o, IC50 for the nucleus accumbens was unchanged, while the IC50's for the striatum and limbic cortex were less. Maximum percentage inhibition was similar to that found for high [Na]o. Although the sensitivity to [Na] varied, synaptosomes from all areas showed Na-dependent uptake; lowering [Na] in the incubation medium from 133.2 to 9.5 mM reduced the uptake by a minimum of 36.9% in the neocortex to a maximum of 78.0% in striatum. Neither the rate of uptake nor the Na-dependence correlated precisely with the sensitivity to cocaine but the two structures which showed the greatest rate of uptake (nucleus accumbens and striatum) also showed the greatest sensitivity to [Na]o. Generally, the rate of uptake correlated with the density of DA terminals and number of cocaine binding sites as reported by others.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- D D Wheeler
- Department of Physiology, Medical University of South Carolina, Charleston 29425
| | | | | |
Collapse
|
17
|
Abstract
The effects of mazindol, cocaine and D-amphetamine were studied in rhesus monkeys trained to self-administer cocaine, and in rats and squirrel monkeys trained to discriminate cocaine from saline. Non-contingent intravenous drug injections were administered to monkeys responding under a session consisting of a 5-min period during which lever-pressing produced food reinforcement and a 60-min session in which responding produced i.v. cocaine infusions (10 or 33 micrograms/kg per infusion). Acute i.v. injections of cocaine (0.1-1.7 mg/kg), D-amphetamine (0.1-1 mg/kg) and the dopamine re-uptake inhibitor mazindol (0.03-0.56 mg/kg) given 5 min before the session decreased self-administration of cocaine, but also decreased rates of behavior maintained by the presentation of food. In both rats and squirrel monkeys trained to discriminate cocaine from saline in a two-lever, food-maintained procedure, mazindol, cocaine and D-amphetamine substituted for cocaine in a dose-related manner. Despite a lack of selectivity to decrease cocaine self-administration as compared to behavior maintained by food, the present data provide some rationale for further consideration of mazindol as a potential pharmacotherapy for stimulant abuse, due to its relatively low abuse liability and cocaine-like discriminative stimulus effects.
Collapse
Affiliation(s)
- R S Mansbach
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298
| | | |
Collapse
|
18
|
Paulus MP, Callaway CW, Geyer MA. Quantitative assessment of the microstructure of rat behavior: II. Distinctive effects of dopamine releasers and uptake inhibitors. Psychopharmacology (Berl) 1993; 113:187-98. [PMID: 7855180 DOI: 10.1007/bf02245696] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effects of four indirect dopamine agonists, d-amphetamine (0.25-4.0 mg/kg), cocaine (2.5-40.0 mg/kg), GBR 12909 (10.0-30.0 mg/kg), and nomifensine (5.0-20.0 mg/kg), on the behavioral organization of movements in an unconditioned motor paradigm were investigated in rats. The extended scaling hypothesis using the fluctuation spectrum of local spatial scaling exponents was used to quantify the geometrical characteristics of movements. The results reveal a qualitatively similar disruption of behavioral organization by lower doses of these drugs. Specifically, rats treated with d-amphetamine (< 2.0 mg/kg), cocaine (< 20.0 mg/kg), GBR 12909 (< 20.0 mg/kg), or nomifensine (< 10.0 mg/kg) exhibited a reduced range in the fluctuation spectrum, reflecting a predominance of meandering movements with local spatial scaling exponents between 1.3 and 1.7. This reduction was accompanied dynamically by a reduced predictability of movement sequences as measured by the dynamical entropy, h. By contrast, higher doses of these drugs produced distinctly different changes in behavioral organization. In particular, 4.0 mg/kg d-amphetamine and 40.0 mg/kg cocaine increased the fluctuation range, reflecting relative increases in both straight and circumscribed movements that are interpreted as a combination of spatially extended and local perseveration. In contrast, high doses of 30.0 mg/kg GBR 12909 and 20.0 mg/kg nomifensine induced only local perseveration. High doses of d-amphetamine, cocaine, GBR 12909 and nomifensine reduced the dynamical entropy, h, indicating an increased predictability of the movement sequences. These results suggest that the generic behavioral change induced by low doses of dopamine agonists is characterized by a reduced variety of path patterns coupled with an increased variability in sequential movement sequences. The differential effects of higher doses of these drugs may be due to their influences on other neurotransmitter systems or differential affinities for different dopamine subsystems.
Collapse
Affiliation(s)
- M P Paulus
- Laboratory of Biological Dynamics and Theoretical Medicine, School of Medicine, University of California, San Diego, La Jolla 92093-0804
| | | | | |
Collapse
|
19
|
Rothman RB, Grieg N, Kim A, De Costa BR, Rice KC, Carroll FI, Pert A. Cocaine and GBR12909 produce equivalent motoric responses at different occupancy of the dopamine transporter. Pharmacol Biochem Behav 1992; 43:1135-42. [PMID: 1475296 DOI: 10.1016/0091-3057(92)90493-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The motoric-stimulating effect of dopamine (DA) reuptake blockers is thought to result from the increase in synaptic dopamine levels, which occurs as a consequence of blockade of DA reuptake. The present study tested measured occupancy of the DA transporter in vivo produced by behaviorally equivalent doses of the DA reuptake blockers GBR12909 (20 mg/kg), cocaine (20 mg/kg), WIN35-065-2 (1 mg/kg), and nomifensine (5 mg/kg). Two methods were used to measure in vivo occupancy of the DA transporter: a) an ex vivo method, in which the ability of whole brain supernatants, prepared from rats administered the test drugs, were tested for their ability to inhibit the reuptake of [3H]DA by striatal synaptosomes; and b) an in vivo binding assay using [3H]N-[1-(2-benzo(b)thiophenyl)cyclohexyl]piperidine ([3H]BTCP) to label the striatal DA transporter in vivo. Considerable data support the notion that this measurement is predictive of transporter occupancy in the nucleus accumbens. Similar results were obtained with both methods: The order of potency for apparent transporter occupancy was GBR12909 >> nomifensine > WIN35-065-2 = cocaine. These data indicate that it takes greater occupancy of the DA transporter by GBR12909 to produce behavioral effects equivalent to those produced by cocaine at lower transporter occupancy. The data of the present study suggest, therefore, that studies relating the effects of DA reuptake inhibitors on DA-mediated motoric behaviors to DA transporter occupancy might facilitate the identification of novel compounds potentially useful for the pharmacotherapy of cocaine abuse.
Collapse
Affiliation(s)
- R B Rothman
- Clinical Psychopharmacology Section, NIDA Addiction Research Center, Baltimore, MD 21224
| | | | | | | | | | | | | |
Collapse
|
20
|
Vaugeois JM, Bonnet JJ, Costentin J. In vivo labelling of the neuronal dopamine uptake complex in the mouse striatum by [3H]GBR 12783. Eur J Pharmacol 1992; 210:77-84. [PMID: 1350989 DOI: 10.1016/0014-2999(92)90654-m] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Various characteristics of the in vivo striatal binding of [3H]GBR 12783 (1-[2-(diphenylmethoxy)-ethyl]-4-(3-phenyl-1[3H]-2-propenyl)pipera zine), a specific ligand of the neuronal dopamine uptake complex, were determined in mice. Increasing doses of the ligand revealed the saturability of the binding at a single site with half-maximal saturation at a dose of approximately 7 mumol/kg and an apparent maximal number of binding sites (Bmax) of 12.8 pmol/mg protein in striatum. Specific binding was prevented by various dopamine uptake blockers, pyrovalerone, GBR 13069, GBR 12783, N-[1-2-benzo(b)thiophenyl)cyclohexyl] piperidine, cocaine, methylphenidate and was inhibited in a stereoselective manner by the enantiomers of nomifensine. Other drugs which are not dopamine uptake blockers either did not modify [3H]GBR 12783 binding (the diphenylbutylpiperazine derivative flupenthixol) or increased it (the diphenylpiperazine derivative flunarizine or the chemically unrelated compounds fenfluramine and SKF 525A). A close correlation was found between occupancy of the striatal [3H]GBR 12783 binding site and the stimulant locomotor effect of the drug. A similar specific striatal binding of [3H]GBR 12783 was evidenced in both NMRI and CD1 strains. It was concluded that [3H]GBR 12783 administered in vivo provides a measure of the density of dopamine uptake sites in mouse striatum.
Collapse
Affiliation(s)
- J M Vaugeois
- Unité de Neuropsychopharmacologie Expérimentale, U.R.A. 1170 CNRS, Faculté de Médecine et Pharmacie de Rouen, Saint-Etienne du Rouvray, France
| | | | | |
Collapse
|
21
|
Irifune M, Shimizu T, Nomoto M. Ketamine-induced hyperlocomotion associated with alteration of presynaptic components of dopamine neurons in the nucleus accumbens of mice. Pharmacol Biochem Behav 1991; 40:399-407. [PMID: 1805243 DOI: 10.1016/0091-3057(91)90571-i] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The underlying mechanisms of ketamine-induced hyperlocomotion were examined in mice. An intraperitoneal (IP) injection of ketamine (3-150 mg/kg) increased locomotor activity in a dose-dependent fashion. A low dose of ketamine (30 mg/kg) produced peak locomotion within the first 10 min followed by a rapid decline. In contrast, a high dose (150 mg/kg) inhibited locomotor activity to the control level during the first 30 min. Thereafter the activity gradually increased and reached a peak at approximately 2 h followed by a gradual decline. The hyperactivities induced by both low and high doses of ketamine were inhibited by a low dose of haloperidol (0.10 mg/kg, IP), a dopamine (DA) receptor antagonist. However, neither a high dose of phenoxybenzamine (10 mg/kg, IP), an alpha-blocker nor a high dose of propranolol (20 mg/kg, IP), a beta-blocker inhibited the hyperactivities. Destruction of catecholaminergic terminals by 6-hydroxydopamine suppressed ketamine-induced hyperlocomotion. Regional brain monoamine assays revealed that, at peak locomotion, a low dose of ketamine (30 mg/kg) selectively increased DA turnover in the nucleus accumbens which is a forebrain region believed to be involved in the initiation and regulation of locomotor activity, while a high dose (150 mg/kg) increased not only DA but also norepinephrine and serotonin turnover in many regions of the brain. In vitro, ketamine slightly provoked [3H]DA release from nucleus accumbens and striatal slices to a similar extent, but inhibited synaptosomal uptake of [3H]DA in the nucleus accumbens to a greater degree than in the striatum.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- M Irifune
- Department of Pharmacology, Faculty of Medicine, Kagoshima University, Japan
| | | | | |
Collapse
|
22
|
Abstract
The recent cloning of the gamma-aminobutyric acid and norepinephrine Na(+)-dependent neurotransmitter transporters has led to new approaches for understanding the structure and function of these important synaptic proteins and provides a conceptual model in which to consider recent advances in the physiology, pharmacology and biochemistry of this gene family.
Collapse
Affiliation(s)
- S G Amara
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510
| | | |
Collapse
|
23
|
Jatlow P, Elsworth JD, Bradberry CW, Winger G, Taylor JR, Russell R, Roth RH. Cocaethylene: a neuropharmacologically active metabolite associated with concurrent cocaine-ethanol ingestion. Life Sci 1991; 48:1787-94. [PMID: 2020260 DOI: 10.1016/0024-3205(91)90217-y] [Citation(s) in RCA: 177] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
High concentrations of cocaethylene (EC), the ethyl ester of benzoylecgonine, were measured in the blood of individuals who had concurrently used cocaine and ethanol. Since the powerful reinforcing effects of cocaine appear to be dependent on inhibition of dopamine reuptake in brain, we compared the effects of EC on the dopamine uptake system and its behavioral effects with those of cocaine. EC was equipotent to cocaine with respect to inhibition of binding of [3H]GBR 12935 to the dopamine reuptake complex, inhibition of [3H]dopamine uptake into synaptosomes and in its ability to increase extracellular dopamine concentration in the nucleus accumbens following its systemic administration to rats. Moreover, in rats, EC and cocaine each increased locomotor activity and rearing to the same extent following i.p. administration. In self-administration studies in primates, EC was approximately equipotent to cocaine in maintaining responding. The in vivo formation of this active, transesterified ethyl homolog of cocaine may contribute to the effects and consequences of combined cocaine and ethanol abuse.
Collapse
Affiliation(s)
- P Jatlow
- Department of Laboratory of Medicine, Yale University School of Medicine, New Haven, CT 06510
| | | | | | | | | | | | | |
Collapse
|