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Pettersson F, Svensson P, Waters S, Waters N, Sonesson C. Synthesis, pharmacological evaluation and QSAR modeling of mono-substituted 4-phenylpiperidines and 4-phenylpiperazines. Eur J Med Chem 2013; 62:241-55. [PMID: 23353756 DOI: 10.1016/j.ejmech.2012.12.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/13/2012] [Accepted: 12/17/2012] [Indexed: 01/11/2023]
Abstract
A series of mono-substituted 4-phenylpiperidines and -piperazines have been synthesized and their effects on the dopaminergic system tested in vivo. The structure activity relationship (SAR) revealed that the position and physicochemical character of the aromatic substituent proved to be critical for the levels of 3,4-dihydroxyphenylacetic acid (DOPAC) in the brain of freely moving rats. In order to investigate how the structural properties of these compounds affect the response, a set of tabulated and calculated physicochemical descriptors were modeled against the in vivo effects using partial least square (PLS) regression. Furthermore, the binding affinities to the dopamine D2 (DA D2) receptor and monoamine oxidase A (MAO A) enzyme were determined for a chosen subset and QSAR models using the same descriptors as in the in vivo model were produced to investigate the mechanisms leading to the observed DOPAC response. These models, in combination with a strong correlation between the levels of striatal DOPAC and the affinities to DA D2 and MAO A, provides a comprehensive understanding of the biological response for compounds in this class.
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Mattsson C, Andreasson T, Waters N, Sonesson C. Systematic in vivo screening of a series of 1-propyl-4-arylpiperidines against dopaminergic and serotonergic properties in rat brain: a scaffold-jumping approach. J Med Chem 2012; 55:9735-50. [PMID: 23043306 DOI: 10.1021/jm300975f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A series of 1-propyl-4-arylpiperidines were synthesized and their effects on the dopaminergic and serotonergic systems tested in vivo and in vitro. Scaffold jumping among five- and six-membered bicyclic aryl rings attached to the piperidine ring had a marked impact on these effects. Potent and selective dopamine D(2) receptor antagonists were generated from 3-indoles, 3-benzoisoxazoles, 3-benzimidazol-2-one, and 3-benzothiophenes. In contrast, 3-benzofuran was a potent and selective inhibitor of monoamine oxidase (MAO) A. The effects of the synthesized compounds on 3,4-dihydroxyphenylacetic acid (DOPAC) levels correlated very well with their affinity for dopamine D(2) receptors and MAO A. In the 4-arylpiperidine series, the most promising compound for development was the 6-chloro-3-(1-propyl-4-piperidyl)-1H-benzimidazol-2-one (19), which displayed typical dopamine D(2) receptor antagonist properties in vivo but produced only a partial reduction on spontaneous locomotor activity. This indicates that the compound may have a lower propensity to induce parkinsonism in patients.
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Woollard A, Waters N, Waters S, Kullingsjö J, Svensson P, Andreasson T, Sonesson C. Q06 Multivariate classification of central nervous system-acting drugs based on in vivo response patterns – profile of pridopidine. Journal of Neurology, Neurosurgery and Psychiatry 2012. [DOI: 10.1136/jnnp-2012-303524.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Pettersson F, Svensson P, Waters S, Waters N, Sonesson C. Synthesis and Evaluation of a Set of Para-Substituted 4-Phenylpiperidines and 4-Phenylpiperazines as Monoamine Oxidase (MAO) Inhibitors. J Med Chem 2012; 55:3242-9. [DOI: 10.1021/jm201692d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Waters S, Tedroff J, Waters N. F10 Correlations between functional measures, voluntary and involuntary motor symptoms in HD -multivariate analysis of cross-sectional and longitudinal registry data. Journal of Neurology, Neurosurgery and Psychiatry 2010. [DOI: 10.1136/jnnp.2010.222620.10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Ponten H, Kullingsjö J, Lagerkvist S, Martin P, Pettersson F, Sonesson C, Waters S, Waters N. In vivo pharmacology of the dopaminergic stabilizer pridopidine. Eur J Pharmacol 2010; 644:88-95. [DOI: 10.1016/j.ejphar.2010.07.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 06/18/2010] [Accepted: 07/11/2010] [Indexed: 11/27/2022]
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Pettersson F, Pontén H, Waters N, Waters S, Sonesson C. Synthesis and evaluation of a set of 4-phenylpiperidines and 4-phenylpiperazines as D2 receptor ligands and the discovery of the dopaminergic stabilizer 4-[3-(methylsulfonyl)phenyl]-1-propylpiperidine (huntexil, pridopidine, ACR16). J Med Chem 2010; 53:2510-20. [PMID: 20155917 DOI: 10.1021/jm901689v] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Modification of the partial dopamine type 2 receptor (D(2)) agonist 3-(1-benzylpiperidin-4-yl)phenol (9a) generated a series of novel functional D(2) antagonists with fast-off kinetic properties. A representative of this series, pridopidine (4-[3-(methylsulfonyl)phenyl]-1-propylpiperidine; ACR16, 12b), bound competitively with low affinity to D(2) in vitro, without displaying properties essential for interaction with D(2) in the inactive state, thereby allowing receptors to rapidly regain responsiveness. In vivo, neurochemical effects of 12b were similar to those of D(2) antagonists, and in a model of locomotor hyperactivity, 12b dose-dependently reduced activity. In contrast to classic D(2) antagonists, 12b increased spontaneous locomotor activity in partly habituated animals. The "agonist-like" kinetic profile of 12b, combined with its lack of intrinsic activity, induces a functional state-dependent D(2) antagonism that can vary with local, real-time dopamine concentration fluctuations around distinct receptor populations. These properties may contribute to its unique "dopaminergic stabilizer" characteristics, differentiating 12b from D(2) antagonists and partial D(2) agonists.
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Dyhring T, Nielsen EØ, Sonesson C, Pettersson F, Karlsson J, Svensson P, Christophersen P, Waters N. The dopaminergic stabilizers pridopidine (ACR16) and (-)-OSU6162 display dopamine D(2) receptor antagonism and fast receptor dissociation properties. Eur J Pharmacol 2009; 628:19-26. [PMID: 19919834 DOI: 10.1016/j.ejphar.2009.11.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 10/23/2009] [Accepted: 11/10/2009] [Indexed: 10/20/2022]
Abstract
A new pharmacological class of CNS ligands with the unique ability to stimulate or suppress motor and behavioral symptoms depending on the prevailing dopaminergic tone has been suggested as "dopaminergic stabilizers". The molecular mode-of-action of dopaminergic stabilizers is not yet fully understood, but they are assumed to act via normalization of dopaminergic signaling, through interactions with the dopamine D(2) receptor. Here we have evaluated the dopaminergic stabilizers pridopidine (ACR16) and (-)-OSU6162, as well as the new compound N-{[(2S)-5-chloro-7-(methylsulfonyl)-2,3-dihydro-1,4-benzodioxin-2-yl]methyl}ethanamine (NS30678) in a series of cellular in vitro dopamine D(2) receptor functional and binding assays. Neither ACR16, (-)-OSU6162, nor NS30678 displayed detectable dopamine D(2) receptor-mediated intrinsic activity, whereas they concentration-dependently antagonized dopamine-induced responses with IC(50) values of 12.9microM, 5.8microM, and 7.0nM, respectively. In contrast to the high-affinity typical antipsychotics haloperidol and raclopride, the dopaminergic stabilizers ACR16 and (-)-OSU6162 both displayed fast dopamine D(2) receptor dissociation properties, a feature that has previously been suggested as a contributing factor to antipsychotic atypicality and attributed mainly to low receptor affinity. However, the finding that NS30678, which is equipotent to haloperidol and raclopride, also displays fast receptor dissociation, suggests that the agonist-like structural motif of the dopaminergic stabilizers tested is a critical dissociation rate determinant. The results demonstrate that dopaminergic stabilizers exhibit fast competitive dopamine D(2) receptor antagonism, possibly allowing for temporally variable and activity-dependent dopamine D(2) receptor occupancy that may partly account for their unique stabilization of dopamine dependent behaviors in vivo.
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Wattiez A, Waters N, Rodriguez B. [In favour of a conservative surgical treatment of ectopic pregnancies]. GYNECOLOGIE, OBSTETRIQUE & FERTILITE 2007; 35:70-3. [PMID: 17229585 DOI: 10.1016/j.gyobfe.2006.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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Forssberg H, Fernell E, Waters S, Waters N, Tedroff J. Altered pattern of brain dopamine synthesis in male adolescents with attention deficit hyperactivity disorder. Behav Brain Funct 2006; 2:40. [PMID: 17144907 PMCID: PMC1698925 DOI: 10.1186/1744-9081-2-40] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 12/04/2006] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Limited data from positron emission tomography (PET) studies of subjects with attention-deficit/hyperactivity disorder (ADHD) indicate alterations in brain dopamine neurotransmission. However, these studies have used conventional univariate approaches that are less sensitive to detect complex interactions that may exist between different brain dopamine pathways and individual symptoms of ADHD. We aimed to investigate these potential interactions in adolescents with ADHD. METHODS We used a 3D PET scan to measure utilization of native L-[11C]-DOPA to map dopamine presynaptic function in various cortical, striatal and midbrain regions in a group of 8 male adolescents with ADHD and 6 age matched controls. To evaluate the interactions between the studied brain regions, multivariate statistical methods were used. RESULTS Abnormal dopaminergic function was found in multiple brain regions of patients with ADHD. A main finding was lower L-[11C]-DOPA utilization in adolescent with ADHD as compared to control subjects, especially in subcortical regions. This pattern of dopaminergic activity was correlated specifically with symptoms of inattention. CONCLUSION Dopamine signalling in the brain plays an important modulatory role in a variety of motor and cognitive functions. We have identified region-specific functional abnormalities in dopaminergic function, which may help better account for the symptoms of ADHD.
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Ray J, Hansen S, Waters N. Links between temperamental dimensions and brain monoamines in the rat. Behav Neurosci 2006; 120:85-92. [PMID: 16492119 DOI: 10.1037/0735-7044.120.1.85] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In 27 female Wistar rats, the authors obtained composite scores on harm avoidance and novelty seeking, as well as 57 measures of monoamines and metabolites from 10 different brain regions. A multivariate regression method was used to discover associations between individual differences in temperament and neurochemistry. Harm-avoidant subjects had low levels of striatal dopamine and high levels of cortical norepinephrine and amygdaloid 5-hydroxyindoleacetic acid. High novelty-seeking scores were linked to low levels of brainstem serotonin and dopamine and to low levels of 5-hydroxyindoleacetic acid in amygdala and accumbens. Moreover, rats scoring high on novelty seeking had higher-than-average levels of norepinephrine in the thalamus and amygdala and of serotonin in the amygdala.
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Ponten H, Sönniksen K, Abrahamsson T, Waters N, Gustafsson B, Hanse E, Groc L. Behavioral and neurochemical repercussions of hippocampal network activity blockade during the neonatal period. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 155:81-6. [PMID: 15763278 DOI: 10.1016/j.devbrainres.2004.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 12/21/2004] [Accepted: 12/22/2004] [Indexed: 11/17/2022]
Abstract
Early destruction of the ventral hippocampus from postnatal day 7 (P7) has been shown to induce behavioral alterations in post-pubertal rats, similar to those observed in models for schizophrenia. Using a single injection of tetanus toxin into the ventral hippocampus at P1, we tested the consequences of an early neonatal activity deprivation (<P7) on behavioral and neurochemical parameters of pre- and post-pubertal rats. We found no significant differences in either behavioral or biochemical pattern, indicating that an early neonate neural activity blockade does not induce behavioral alterations in pre- and post-puberty rats.
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Gefvert O, Lindström LH, Waters N, Waters S, Carlsson A, Tedroff J. Different corticostriatal patterns of L-DOPA utilization in patients with untreated schizophrenia and patients treated with classical antipsychotics or clozapine. Scand J Psychol 2003; 44:289-92. [PMID: 12914593 DOI: 10.1111/1467-9450.00347] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Positron emission tomography (PET) has been shown to be of great importance in elucidating the mechanism of action of antipsychotic drugs. In psychotic patients L-[11C]DOPA PET has been used to demonstrate some differences in dopaminergic activity compared with that in healthy volunteers. Ten healthy volunteers were investigated with PET and L-[11C]DOPA. Ten drug-free patients with psychosis, nine stable schizophrenics treated with clozapine, and nine stable patients treated with classical antipsychotics were also investigated with L-[11C]DOPA. Principal-component analysis was employed for the analysis of L-[11C]DOPA Ki values across a number of corticostriatal brain regions. These data revealed a significant three-component model with clear-cut separation between healthy controls and patients with unmedicated schizophrenia. Stable optimal treatment with either classical neuroleptics or clozapine partially, albeit differentially, reversed the aberrant patterns seen in drug-free schizophrenia. It can thus be concluded that schizophrenia is associated with abnormal patterns of L-[11C]DOPA utilization in corticostriatal systems. Treatment with clozapine or classical neuroleptics induces partial, albeit differential, normalization of the abnormal patterns seen in untreated schizophrenia.
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Nilsson M, Waters S, Waters N, Carlsson A, Carlsson ML. A behavioural pattern analysis of hypoglutamatergic mice--effects of four different antipsychotic agents. J Neural Transm (Vienna) 2002; 108:1181-96. [PMID: 11725821 DOI: 10.1007/s007020170008] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In a hypoglutamatergic rodent model, we have observed certain behaviours that might have relevance for the cognitive impairments seen in autism and schizophrenia. Thus, hypoglutamatergic mice show defective habituation, impaired attention, a meagre behavioural repertoire and a general behavioural primitivization. The aim of the present study was to characterise and quantify changes in movement pattern in mice rendered hypoglutamatergic by means of MK-801 treatment, using an automated video tracking system. Further, the effects of four different antipsychotic drugs, the classical neuroleptic haloperidol, the atypical antipsychotic clozapine, the DA D2/5-HT2A antagonist risperidone and the selective 5-HT2A-receptor antagonist M100907, were compared with respect to effects on NMDA antagonist-induced movement pattern alterations. We found that each receptor antagonist had a unique effect on the MK-801-induced behavioural primitivization. Haloperidol was unable to affect the monotonous behaviour induced by MK-801, while risperidone, clozapine and M100907 produced movement patterns of high intricacy.
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Carlsson A, Waters N, Holm-Waters S, Tedroff J, Nilsson M, Carlsson ML. Interactions between monoamines, glutamate, and GABA in schizophrenia: new evidence. Annu Rev Pharmacol Toxicol 2001; 41:237-60. [PMID: 11264457 DOI: 10.1146/annurev.pharmtox.41.1.237] [Citation(s) in RCA: 530] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In spite of its proven heuristic value, the dopamine hypothesis of schizophrenia is now yielding to a multifactorial view, in which the other monoamines as well as glutamate and GABA are included, with a focus on neurotransmitter interactions in complex neurocircuits. The primary lesion(s) in schizophrenia does not necessarily involve any of these neurotransmitters directly but could deal with a more general defect, such as a faulty connectivity of developmental origin. Nevertheless, a precise identification of neurotransmitter aberrations in schizophrenia will probably provide clues for a better understanding of the disease and for the development of new treatment and prevention strategies.
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Holm J, Nilsson U, Waters N, Waters S, Jonsson O. Production of free radicals measured by spin trapping during operations for stenosis of the carotid artery. THE EUROPEAN JOURNAL OF SURGERY = ACTA CHIRURGICA 2001; 167:4-9. [PMID: 11213819 DOI: 10.1080/110241501750069738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
OBJECTIVES To analyse production of free radicals during operations for stenosis of the internal carotid artery. SETTING University hospital, Sweden. SUBJECTS 10 patients operated on for carotid artery stenosis. INTERVENTIONS Blood samples were repeatedly drawn from the sigmoid sinus through a catheter in the internal jugular vein on the same side, before, during, and after clamping of the internal carotid artery. OXANOH was added to the blood samples in vitro and the radical production calculated from the amount oxidised to OXANO as electron spin resonance. MAIN OUTCOME MEASURES The relation between radical production and certain clinical variables investigated by partial least squares regression analysis. RESULTS There were several significant relations. High systolic blood pressure and advanced age were associated with low, and severe degree of stenosis with increased, free radical production. Certain anaesthetic drugs as well as blood variables also influenced the production of radicals. CONCLUSIONS The technique used seems to offer the possibility to find and study methods to reduce free radical production during this kind of operation.
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Le Roch K, Sestier C, Dorin D, Waters N, Kappes B, Chakrabarti D, Meijer L, Doerig C. Activation of a Plasmodium falciparum cdc2-related kinase by heterologous p25 and cyclin H. Functional characterization of a P. falciparum cyclin homologue. J Biol Chem 2000; 275:8952-8. [PMID: 10722743 DOI: 10.1074/jbc.275.12.8952] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several Plasmodium falciparum genes encoding cdc2-related protein kinases have been identified, but the modalities of their regulation remains largely unexplored. In the present study, we investigated the regulation in vitro of PfPK5, a putative homologue of Cdk1 (cdc2) in P. falciparum. We show that (i) PfPK5 is efficiently activated by heterologous (human) cyclin H and p25, a cyclin-like molecule that specifically activates human Cdk5; (ii) the activated enzyme can be inhibited by chemical Cdk inhibitors; (iii) Pfmrk, a putative P. falciparum homologue of the Cdk-activating kinase, does neither activate nor phosphorylate PfPK5; and (iv) PfPK5 is able to autophosphorylate in the presence of a cyclin. Taken together, these results suggest that the regulation of Plasmodium Cdks may differ in important aspects from that of their human counterparts. Furthermore, we cloned an open reading frame encoding a novel P. falciparum protein possessing maximal homology to cyclin H from various organisms, and we show that this protein, called Pfcyc-1, is able to activate recombinant PfPK5 in vitro with an efficiency similar to that of human cyclin H and p25. This work opens the way to the development of screening procedures aimed at identifying compounds that specifically target the parasite Cdks.
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Carlsson A, Waters N, Carlsson ML. Neurotransmitter interactions in schizophrenia-therapeutic implications. Eur Arch Psychiatry Clin Neurosci 2000; 249 Suppl 4:37-43. [PMID: 10654107 DOI: 10.1007/pl00014183] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The search for new and improved antipsychotic agents has increased in intensity during the past five years. The era of searching for non-toxic copies of clozapine has been followed by several different lines of research, some of which pursue the traditional dopamine track, although at a higher level of sophistication, whereas others focus on other neurotransmitters, such as serotonin and glutamate. Emerging knowledge about the interactions between different neurotransmitters in complex neurocircuits opens up possibilities for achieving antipsychotic activity by interfering with many different neurotransmitters. Most intriguing is the finding in animal experimental models, indicating that it should be possible to alleviate psychotic conditions by stabilizing rather than paralyzing neurocircuits, thus avoiding the risk of motor and mental side effects of the currently used drugs. Among these new classes, dopaminergic stabilizers and 5-HT2A receptor antagonists appear to offer the most promise at present. In a longer perspective, drugs interfering with glutamate function via different mechanisms may also turn out to be useful, especially in the control of negative symptoms.
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Carlsson A, Waters N, Waters S, Carlsson ML. Network interactions in schizophrenia - therapeutic implications. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2000; 31:342-9. [PMID: 10719161 DOI: 10.1016/s0165-0173(99)00050-8] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Research into the role of neurotransmitters and neural networks in the pathogenesis of schizophrenia has been remarkably successful in recent years. The hypothesis postulating a dopamine dysfunction, which has for a long time been supported only by indirect evidence, has received direct support by means of sophisticated imaging techniques. Interactions between dopamine and several other neurotransmitters in complex neural networks have been revealed, largely thanks to the advent of an array of new pharmacological probes. Two major pharmacological models of schizophrenia, based on hyperdopaminergia and hypoglutamatergia, respectively, are ready for clinical testing. In addition, the hypothesis of network stabilization as a major therapeutic strategy in psychiatry and neurology has now reached the 'proof-of-concept' level. From a therapeutic perspective, several ongoing and forthcoming clinical trials, using drugs acting on dopaminergic, serotonergic and glutamatergic receptors, give rise to optimism.
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Abstract
The search for new and improved antipsychotic agents has escalated during the past five years. The era of searching for non-toxic copies of clozapine has been followed by several different lines of research, some of which pursue the traditional dopamine track, although at a higher level of sophistication, whereas others focus on other neurotransmitters, such as serotonin and glutamate. Emerging knowledge about the interactions between different neurotransmitters in complex neurocircuits opens up possibilities for achieving antipsychotic activity by interfering with many different neurotransmitters. Most intriguing is the finding in animal experimental models, indicating that it should be possible to alleviate psychotic conditions by stabilizing rather than paralyzing neurocircuits, thus avoiding the risk of motor and mental side effects of the currently used drugs. Among these new classes dopaminergic stabilizers and 5-HT2A receptor antagonists seem to offer most promise at present. In a longer perspective, drugs interfering with glutamate function via different mechanisms may also turn out to be useful, especially in the control of negative symptoms.
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Tedroff J, Ekesbo A, Sonesson C, Waters N, Carlsson A. Long-lasting improvement following (-)-OSU6162 in a patient with Huntington's disease. Neurology 1999; 53:1605-6. [PMID: 10534281 DOI: 10.1212/wnl.53.7.1605] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Carlsson ML, Martin P, Nilsson M, Sorensen SM, Carlsson A, Waters S, Waters N. The 5-HT2A receptor antagonist M100907 is more effective in counteracting NMDA antagonist- than dopamine agonist-induced hyperactivity in mice. J Neural Transm (Vienna) 1999; 106:123-9. [PMID: 10226932 DOI: 10.1007/s007020050144] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The purpose of the present study was to compare the effectiveness of the selective 5-HT2A antagonist M100907 in different psychosis models. The classical neuroleptic haloperidol was used as reference compound. Two hyperdopaminergia and two hypoglutamatergia mouse models were used. Hyperdopaminergia was produced by the DA releaser d-amphetamine or the DA uptake inhibitor GBR 12909. Hypoglutamatergia was produced by the un-competitive NMDA receptor antagonist MK-801 or the competitive NMDA receptor antagonist D-CPPene. M100907 was found to counteract the locomotor stimulant effects of the NMDA receptor antagonists MK-801 and D-CPPene, but spontaneous locomotion, d-amphetamine- and GBR-12909-induced hyperactivity were not significantly affected. Haloperidol, on the other hand, antagonized both NMDA antagonist- and DA agonist-induced hyperactivity, as well as spontaneous locomotion in the highest dose used. Based on the present and previous results we draw the conclusion that 5-HT2A receptor antagonists are particularly effective against behavioural anomalies resulting from hypoglutamatergia of various origins. The clinical implications of our results and conclusions would be that a 5-HT2A receptor antagonist, due to i a the low side effect liability, could be the preferable treatment strategy in various disorders associated with hypoglutamatergia; such conditions might include schizophrenia, childhood autism and dementia disorders.
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Carlsson A, Hansson LO, Waters N, Carlsson ML. A glutamatergic deficiency model of schizophrenia. Br J Psychiatry Suppl 1999:2-6. [PMID: 10211132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Although the presence of hyperdopaminergia has been demonstrated in the brains of people with schizophrenia, at least in some circumstances, other neurotransmitters are important in this disorder, and a glutamatergic deficiency model of schizophrenia is proposed. It is suggested that the amount of sensory input allowed to reach the cerebral cortex is restricted by an inhibitory effect of the striatal complexes on the thalamus, thereby protecting it from being overwhelmed. Several strands of evidence are presented to support the concept that a weakened glutamatergic tone increases the risk of sensory overload and of exaggerated responses in the monoaminergic systems that could result in psychosis.
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Ekesbo A, Torstenson R, Hartvig P, Carlsson A, Sonesson C, Waters N, Tedroff J, Långström B. Effects of the substituted (S)-3-phenylpiperidine (-)-OSU6162 on PET measurements of [11C]SCH23390 and [11C]raclopride binding in primate brains. Neuropharmacology 1999; 38:331-8. [PMID: 10219971 DOI: 10.1016/s0028-3908(98)00200-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The substituted (S)-3-phenylpiperidine (-)-OSU6162 belongs to a novel class of functional modulators of dopaminergic systems. In vivo, (-)-OSU6162 has a unique stabilising profile on dopaminergic functions. In vitro this compound exhibits low affinity for the dopamine D2 receptor, but due to its similarity to neuroleptics on brain dopaminergic neurochemistry and different postsynaptic effects it has been characterised as a preferential dopamine autoreceptor antagonist. To further clarify the effects of (-)-OSU6162 on the postjunctional nigrostriatal dopaminergic system, dopamine receptor binding was measured in rhesus monkeys (Macaca mulatta) by positron emission tomography (PET) using the D1 and D2 dopamine receptor radioligands [11C]SCH23390 and [11C]raclopride respectively, before and during continuous intravenous infusions of(-)-OSU6162. Additionally, the test-retest variability of sequential [11C]SCH23390 scans was estimated. Following the administration of (-)-OSU6162, [11C]raclopride binding in striatum was dose-dependently decreased with a 76% reduction occurring after 3.0 mg/kg per h continuous infusion. Whereas (-)-OSU6162 in the lower doses had no effect on [11C]SCH23390 binding, the highest dose, 3.0 mg/kg per h, increased [11C]SCH23390 binding, which may indicate a potentiating effect on D1 dopamine receptor mediated functions. Thus, in contrast to the conditions in vitro, (-)-OSU6162 produces a high displacement of raclopride from D2 receptors in vivo.
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Martin P, Waters N, Schmidt CJ, Carlsson A, Carlsson ML. Rodent data and general hypothesis: antipsychotic action exerted through 5-Ht2A receptor antagonism is dependent on increased serotonergic tone. J Neural Transm (Vienna) 1998; 105:365-96. [PMID: 9720968 DOI: 10.1007/s007020050064] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The locomotor stimulation induced by the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (dizocilpine) in mice was regarded as a model of at least some aspects of schizophrenia. The serotonin synthesis inhibitor dl-p-chlorophenylalanine (PCPA) was used to evaluate the involvement of endogenous serotonin in (a) the induction of MK-801-induced hyperlocomotion in NMRI mice, and (b) the inhibition of MK-801-induced hyperlocomotion by each of five monoaminergic antagonists (M100907, clozapine, olanzapine, raclopride, SCH23390). Further, brain monoaminergic biochemistry was characterised in rats and mice after various drug treatments. PCPA pretreatment did not significantly reduce MK-801-induced hyperlocomotion in any of the experiments performed; however in a meta-analysis of six experiments, the locomotion displayed by MK-801-treated animals was diminished 17% by PCPA pretreatment. The selective 5-HT2A receptor antagonist M100907 exerted a dose-dependent inhibition of MK-801-induced hyperlocomotion. This effect was abolished in mice pretreated with PCPA, but could be restored in a dose-dependent manner by restitution of endogenous 5-HT by means of 5-hydroxytryptophan (5-HTP). On the other hand, the inhibition of MK-801-induced hyperlocomotion exerted by the selective dopamine D-2 receptor antagonist raclopride or the dopamine D-1 receptor antagonist SCH23390 was unaffected by PCPA pretreatment. The antipsychotics clozapine and olanzapine displayed a split profile. Hence, the inhibitory effect on MK-801-induced hyperlocomotion exerted by low doses of these compounds was diminished after PCPA pretreatment, while inhibition exerted by higher doses was unaffected by PCPA. These results suggest that (1) MK-801-induced hyperlocomotion is accompanied by an activation of, but is not fully dependent upon, brain serotonergic systems. (2) In the hypoglutamatergic state induced by MK-801, endogenous serotonin exerts a stimulatory effect on locomotion through an action at 5-HT2A receptors, an effect that is almost completely counterbalanced by a concomitant inhibitory impact on locomotion, mediated through stimulation of serotonin receptors other than 5-HT2A receptors. M100907, by blocking 5-HT2A receptors, unveils the inhibitory effect exerted on locomotion by these other serotonin receptors. (3) Dopamine D-2 receptor antagonistic properties of antipsychotic compounds, when they come into play, override 5-HT2A receptor antagonism. Possible implications for the treatment of schizophrenia with 5-HT2A receptor antagonists are discussed. It is hypothesized that treatment response to such agents is dependent on increased serotonergic tone.
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