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Rajagopal L, Mahjour S, Huang M, Ryan CA, Elzokaky A, Csakai AJ, Orr MJ, Scheidt K, Meltzer HY. NU-1223, a simplified analog of alstonine, with 5-HT 2cR agonist-like activity, rescues memory deficit and positive and negative symptoms in subchronic phencyclidine mouse model of schizophrenia. Behav Brain Res 2023; 454:114614. [PMID: 37572758 DOI: 10.1016/j.bbr.2023.114614] [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: 03/27/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/14/2023]
Abstract
The serotonin (5-HT)2 C receptor(R) is a widely distributed G-protein-coupled receptor, expressed abundantly in the central nervous system. Alstonine is a natural product that has significant properties of atypical antipsychotic drugs (AAPDs), in part attributed to 5-HT2 CR agonism. Based on alstonine, we developed NU-1223, a simplified β carboline analog of alstonine, which shows efficacies comparable to alstonine and to other 5-HT2 CR agonists, Ro-60-0175 and lorcaserin. The 5-HT2 CR antagonism of some APDs, including olanzapine, contributes to weight gain, a major side effect which limits its tolerability, while the 5-HT2 CR agonists and/or modulators, may minimize weight gain. We used the well-established rodent subchronic phencyclidine (PCP) model to test the efficacy of NU-1223 on episodic memory, using novel object recognition (NOR) task, positive (locomotor activity), and negative symptoms (social interaction) of schizophrenia (SCH). We found that NU-1223 produced both transient and prolonged rescue of the subchronic PCP-induced deficits in NOR and SI. Further, NU-1223, but not Ro-60-0175, blocked PCP and amphetamine (AMPH)-induced increase in LMA in subchronic PCP mice. These transient efficacies in LMA were blocked by the 5-HT2 CR antagonist, SB242084. Sub-chronic NU-1223 treatment rescued NOR and SI deficits in subchronic PCP mice for at least 39 days after 3 days injection. Chronic treatment with NU-1223, ip, twice a day for 21 days, did not increase average body weight vs olanzapine. These findings clearly indicate NU-1223 as a class of small molecules with a possible 5-HT2 CR-agonist-like mechanism of action, attributing to its efficacy. Additional in-depth receptor mechanistic studies are warranted, as this small molecule, both transiently and chronically rescued PCP-induced deficits. Furthermore, NU-1223 did not induce weight gain post long-term administrations vs AAPDs such as olanzapine, making NU-1223 a putative therapeutic compound for SCH.
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Affiliation(s)
- Lakshmi Rajagopal
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Sanaz Mahjour
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Mei Huang
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Chelsea A Ryan
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ahmad Elzokaky
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Adam J Csakai
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Meghan J Orr
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Karl Scheidt
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA; Department of Pharmacology, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Herbert Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA.
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Gouda B, Sinha SN, Chalamaiah M, Vakdevi V, Shashikala P, Veeresh B, Surekha VM, Kasturi V, Boiroju NK. Sex Differences in Animal Models of Sodium-Valproate-Induced Autism in Postnatal BALB/c Mice: Whole-Brain Histoarchitecture and 5-HT2A Receptor Biomarker Evidence. BIOLOGY 2022; 11:biology11010079. [PMID: 35053076 PMCID: PMC8772829 DOI: 10.3390/biology11010079] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/27/2021] [Accepted: 12/29/2021] [Indexed: 02/04/2023]
Abstract
Simple Summary Valproic acid (VPA) is a well-known antiepileptic medication and mood stabiliser that is frequently prescribed for the treatment of epilepsy, particularly in children, and has proven human teratogenic activity. VPA inhibits histone deacetylase, which causes teratogenicity and cell toxicity. VPA-induced autism in rodents during the pre- and postnatal periods has shown the development of an autism-like phenotype. In mice, the 14th postnatal day is thought to correspond to the third trimester of human development; it is an important period in which neuronal migration, differentiation, myelination, synaptogenesis and gliogenesis occur in the cerebellum, striatum and hippocampus. Therefore, we exposed postnatal day 14 (PND 14) mice to VPA, which resulted in autistic-like behaviours manifested as reduced social interaction, increased repetitive stereotyped behaviour and anxiety, cognitive dysfunction, lowered sensitivity to pain and neurodevelopmental delay. BALB/c mice were used in this work because they are less reactive to social contact in VPA-induced autism than many other inbred mouse strains, such as C57/129 mice. In humans, two to three times more men are affected by autism spectrum disorder (ASD) than women, and, for this reason, the current study compares the histopathological changes and 5-hydroxy-tryptamine 2A (5-HT2A) receptor protein expression in the brain tissue of male and female animals with VPA-induced autism. Abstract Autism spectrum disorder (ASD) is characterised by problems with social interaction, verbal and nonverbal communication and repetitive behaviour. In mice, the 14th postnatal day is believed to correspond to the third trimester of human embryonic development and is considered a vital period for central nervous system development. It has been shown that ASD affects 2 to 3 times more male than female individuals. In the present study, ASD was induced in 14 postnatal day (PND) BALB/c mice using valproic acid (VPA). VPA administration brought about substantial differences in the histoarchitecture of the brain in both male and female mice, linked to behavioural deficits. We observed that both male and female mice showed similar morphological changes in the prefrontal cortex, hippocampus and Purkinje cells. We also observed hair loss from PND 17 to 25, which was again similar between male and female mice. However, there were higher rates of change in the cerebral cortex, frontal cortex and temporal lobe and hippocampus in VPA-treated male animals. With respect to the cerebellum, we did not observe any alterations by haematoxylin and eosin (H&E) staining, but detailed morphological observation using scanning electron microscopy (SEM) showed a higher rate of phenotype changes in VPA-treated male animals. Moreover, 5-HT2A receptor protein levels were upregulated in the cerebral cortex, hippocampus and Purkinje cells in VPA-treated male mice compared with control animals and VPA-treated female mice, as shown by immunohistochemical analysis. Based on all these findings, we conclude that male animals are more susceptible to VPA-induced ASD than females.
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Affiliation(s)
- Balaji Gouda
- Division of Food Safety, Indian Council of Medical Research, National Institute of Nutrition, Jamai-Osmania, Hyderabad 500007, India; (B.G.); (V.V.); (V.K.)
| | - Sukesh Narayan Sinha
- Division of Food Safety, Indian Council of Medical Research, National Institute of Nutrition, Jamai-Osmania, Hyderabad 500007, India; (B.G.); (V.V.); (V.K.)
- Correspondence: ; Tel.: +91-40-27197405
| | - Meram Chalamaiah
- Drug Safety Division, Indian Council of Medical Research, National Institute of Nutrition, Jamai-Osmania, Hyderabad 500007, India;
| | - Validandi Vakdevi
- Division of Food Safety, Indian Council of Medical Research, National Institute of Nutrition, Jamai-Osmania, Hyderabad 500007, India; (B.G.); (V.V.); (V.K.)
| | - Patangay Shashikala
- Department of Pharmacy, University College of Technology, Osmania University, Hyderabad 500027, India;
| | - Bantal Veeresh
- Department of Pharmacology, G. Pulla Reddy College of Pharmacy, Osmania University, Hyderabad 500028, India;
| | - Venkata Mullapudi Surekha
- Division of Pathology and Microbiology, Indian Council of Medical Research, National Institute of Nutrition, Jamai-Osmania, Hyderabad 500007, India;
| | - Vasudev Kasturi
- Division of Food Safety, Indian Council of Medical Research, National Institute of Nutrition, Jamai-Osmania, Hyderabad 500007, India; (B.G.); (V.V.); (V.K.)
| | - Naveen Kumar Boiroju
- Division of Biostatistics, Indian Council of Medical Research, National Institute of Nutrition, Tarnaka, Hyderabad 500007, India;
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de la Fuente Revenga M, Shah UH, Nassehi N, Jaster AM, Hemanth P, Sierra S, Dukat M, González-Maeso J. Psychedelic-like Properties of Quipazine and Its Structural Analogues in Mice. ACS Chem Neurosci 2021; 12:831-844. [PMID: 33400504 PMCID: PMC7933111 DOI: 10.1021/acschemneuro.0c00291] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Known classic psychedelic serotonin 2A receptor (5-HT2AR) agonists retain a tryptamine or phenethylamine at their structural core. However, activation of the 5-HT2AR can be elicited by drugs lacking these fundamental scaffolds. Such is the case of the N-substituted piperazine quipazine. Here, we show that quipazine bound to and activated 5-HT2AR as measured by [3H]ketanserin binding displacement, Ca2+ mobilization, and accumulation of the canonical Gq/11 signaling pathway mediator inositol monophosphate (IP1) in vitro and in vivo. Additionally, quipazine induced via 5-HT2AR an expression pattern of immediate early genes (IEG) in the mouse somatosensory cortex consistent with that of classic psychedelics. In the mouse head-twitch response (HTR) model of psychedelic-like action, quipazine produced a lasting effect with high maximal responses during the peak effect that were successfully blocked by the 5-HT2AR antagonist M100907 and absent in 5-HT2AR knockout (KO) mice. The acute effect of quipazine on HTR appeared to be unaffected by serotonin depletion and was independent from 5-HT3R activation. Interestingly, some of these features were shared by its deaza bioisostere 2-NP, but not by other closely related piperazine congeners, suggesting that quipazine might represent a distinct cluster within the family of psychoactive piperazines. Together, our results add to the mounting evidence that quipazine's profile matches that of classic psychedelic 5-HT2AR agonists at cellular signaling and behavioral pharmacology levels.
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Affiliation(s)
- Mario de la Fuente Revenga
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
- Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia 23219, United States
| | - Urjita H Shah
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Nima Nassehi
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Alaina M Jaster
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Prithvi Hemanth
- Department of Medicinal Chemistry, Virginia Commonwealth University School of Pharmacy, Richmond, Virginia 23298, United States
| | - Salvador Sierra
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Malgorzata Dukat
- Department of Medicinal Chemistry, Virginia Commonwealth University School of Pharmacy, Richmond, Virginia 23298, United States
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
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Phan DH, Shin EJ, Sharma N, Hoang Yen TP, Dang DK, Lee YS, Lee YJ, Nah SY, Cheong JH, Jeong JH, Kim HC. 5-HT 2A receptor-mediated PKCδ phosphorylation is critical for serotonergic impairments induced by p-chloroamphetamine in mice. Food Chem Toxicol 2020; 141:111395. [PMID: 32437895 DOI: 10.1016/j.fct.2020.111395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/18/2020] [Accepted: 04/29/2020] [Indexed: 02/06/2023]
Abstract
p-Chloroamphetamine (PCA), an amphetamine derivative, has been shown to induce serotonergic toxicity. However, the precise mechanism of serotonergic toxicity induced by PCA remains unclear. In this study, PCA treatment (20 mg/kg, i.p.) did not significantly change 5-HT1A receptor gene expression, but significantly increased 5-HT2A receptor gene expression. Furthermore, 5-HT2A receptor antagonist MDL11939, but not 5-HT1A receptor antagonist WAY100635, significantly attenuated PCA-induced serotonergic impairments. We investigated whether PCA activated a specific isoform of protein kinase C (PKC), since previous evidence indicated the involvement of PKC in neurotoxicity induced by amphetamines. We observed that PCA treatment significantly increased the expression levels of PKCδ among all PKC isoforms. MDL11939 treatment significantly attenuated PCA-induced phosphorylation of PKCδ. However, PCA-induced increase in 5-HT2A receptor gene expression was not altered by rottlerin (a pharmacological inhibitor of PKCδ) in mice, suggesting that 5-HT2A receptor is an upstream molecule for the activation of PKCδ. Rottlerin or PKCδ knockout significantly attenuated serotonergic behaviors. However, MDL11939 did not show any additional effects against the attenuation caused by PKCδ knockout in mice, suggesting that PKCδ gene is a molecular target for 5-HT2A receptor-mediated serotonergic effects. Our results suggest that 5-HT2A receptor mediates PCA-induced serotonergic impairments via activation of PKC.δ.
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Affiliation(s)
- Dieu Hien Phan
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea; School of Medicine and Pharmacy - Hoa Quy Ward, The University of Da Nang, Da Nang 550000, Viet Nam
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Naveen Sharma
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Tran Phi Hoang Yen
- Faculty of Pharmacy, University of Medicine and Pharmacy of Ho Chi Minh City, 710000, Viet Nam
| | - Duy-Khanh Dang
- Pharmacy Faculty, Can Tho University of Medicine and Pharmacy, Can Tho City, 900000, Viet Nam
| | - Yong Sup Lee
- Department of Life and Nanopharmaceutical Sciences, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Yu Jeung Lee
- Clinical Pharmacy, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, Seoul, 05029, Republic of Korea
| | - Jae Hoon Cheong
- Department of Pharmacy, Sahmyook University, Seoul, 01795, Republic of Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea.
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Jensen AA, Halberstadt AL, Märcher-Rørsted E, Odland AU, Chatha M, Speth N, Liebscher G, Hansen M, Bräuner-Osborne H, Palner M, Andreasen JT, Kristensen JL. The selective 5-HT 2A receptor agonist 25CN-NBOH: Structure-activity relationship, in vivo pharmacology, and in vitro and ex vivo binding characteristics of [ 3H]25CN-NBOH. Biochem Pharmacol 2020; 177:113979. [PMID: 32298690 DOI: 10.1016/j.bcp.2020.113979] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 04/10/2020] [Indexed: 01/16/2023]
Abstract
The remarkable effects exhibited by classical psychedelics in recent clinical trials have spawned considerable interest in 5-HT2A receptor (5-HT2AR) activation as a treatment strategy for several psychiatric/cognitive disorders. In this study we have continued our development of 25CN-NBOH, one of the most 5-HT2AR-selective agonists reported to date, as a pharmacological tool for exploration of 5-HT2AR expression and functions. The importance of the 2' and 3' positions in 25CN-NBOH as structural hotspots for its 5-HT2AR activity was investigated by synthesis and pharmacological characterization of six novel analogs at 5-HT2AR and 5-HT2CR in binding and functional assays. While the 5-HT2AR activity of 25CN-NBOH was retained in 3'-methyl, 2',3'-chroman, 2',3'-dihydrofuran and 2',3'-furan analogs, the 3'-methoxy and 3'-ethyl analogs displayed substantially lower binding affinities and agonist potencies than 25CN-NBOH. Interestingly, the 2',3'-substitution pattern was also a key determinant of agonist efficacy, as all six analogs exhibited low-efficacy partial agonism or de facto antagonism at the 5-HT2AR in the functional assays. Systemic administration of 25CN-NBOH and its close structural analog 25CN-NBMD induced robust head-twitch response in mice, a well-established behavioural effect of 5-HT2AR activation in vivo, and 25CN-NBOH mediated robust reductions in the activity of mice in an anxiety-related marble burying assay, which supports the proposed beneficial effects of 5-HT2AR activation on disorders characterized by cognitive rigidity. Finally, tritiated 25CN-NBOH exhibited high 5-HT2AR binding affinity (KD ~1 nM) and selectivity against 5-HT2BR and 5-HT2CR in equilibrium and kinetic binding studies of the recombinant receptors, and in concordance [3H]25CN-NBOH displayed substantial specific, ketanserin-sensitive binding to cortex and small levels of binding to choroid plexus in rat brain slices in autoradiography studies. In conclusion, this work delineates the subtle molecular determinants of the 5-HT2AR activity in 25CN-NBOH, substantiates the potential in this compound and its analogs as tools for in vivo studies of the 5-HT2AR, and introduces a novel selective agonist radioligand as another potentially valuable tool for future explorations of this receptor.
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Affiliation(s)
- Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark.
| | - Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States; Research Service, VA San Diego Healthcare System, La Jolla, CA, United States
| | - Emil Märcher-Rørsted
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Anna U Odland
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Muhammad Chatha
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States
| | - Nikolaj Speth
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Gudrun Liebscher
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Martin Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Mikael Palner
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark; Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Jesper T Andreasen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Jesper L Kristensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
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Abiero A, Botanas CJ, Sayson LV, Custodio RJ, de la Peña JB, Kim M, Lee HJ, Seo JW, Ryu IS, Chang CM, Yang JS, Lee YS, Jang CG, Kim HJ, Cheong JH. 5-Methoxy-α-methyltryptamine (5-MeO-AMT), a tryptamine derivative, induces head-twitch responses in mice through the activation of serotonin receptor 2a in the prefrontal cortex. Behav Brain Res 2019; 359:828-835. [DOI: 10.1016/j.bbr.2018.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/10/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022]
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7
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Tran HQ, Lee Y, Shin EJ, Jang CG, Jeong JH, Mouri A, Saito K, Nabeshima T, Kim HC. PKCδ Knockout Mice Are Protected from Dextromethorphan-Induced Serotonergic Behaviors in Mice: Involvements of Downregulation of 5-HT 1A Receptor and Upregulation of Nrf2-Dependent GSH Synthesis. Mol Neurobiol 2018; 55:7802-7821. [PMID: 29468562 DOI: 10.1007/s12035-018-0938-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 01/28/2018] [Indexed: 12/12/2022]
Abstract
We investigated whether a specific serotonin (5-HT) receptor-mediated mechanism was involved in dextromethorphan (DM)-induced serotonergic behaviors. We firstly observed that the activation of 5-HT1A receptor, but not 5-HT2A receptor, contributed to DM-induced serotonergic behaviors in mice. We aimed to determine whether the upregulation of 5-HT1A receptor induced by DM facilitates the specific induction of certain PKC isoform, because previous reports suggested that 5-HT1A receptor activates protein kinase C (PKC). A high dose of DM (80 mg/kg, i.p.) induced a selective induction of PKCδ out of PKCα, PKCβI, PKCβII, PKCξ, and PKCδ in the hypothalamus of wild-type (WT) mice. More importantly, 5-HT1A receptor co-immunoprecipitated PKCδ in the presence of DM. Consistently, rottlerin, a pharmacological inhibitor of PKCδ, or PKCδ knockout significantly protected against increases in 5-HT1A receptor gene expression, 5-HT turnover rate, and serotonergic behaviors induced by DM. Treatment with DM resulted in an initial increase in nuclear factor erythroid-2-related factor 2 (Nrf2) nuclear translocation and DNA-binding activity, γ-glutamylcysteine (GCL) mRNA expression, and glutathione (GSH) level. This compensative induction was further potentiated by rottlerin or PKCδ knockout. However, GCL mRNA and GSH/GSSG levels were decreased 6 and 12 h post-DM. These decreases were attenuated by PKCδ inhibition. Our results suggest that interaction between 5-HT1A receptor and PKCδ is critical for inducing DM-induced serotonergic behaviors and that inhibition of PKCδ attenuates the serotonergic behaviors via downregulation of 5-HT1A receptor and upregulation of Nrf2-dependent GSH synthesis.
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MESH Headings
- Acetophenones/pharmacology
- Animals
- Behavior, Animal
- Benzopyrans/pharmacology
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Dextromethorphan
- Down-Regulation
- Glutamate-Cysteine Ligase/genetics
- Glutamate-Cysteine Ligase/metabolism
- Glutathione/biosynthesis
- Glutathione Disulfide/metabolism
- Hypothalamus/metabolism
- Hypothermia, Induced
- Isoenzymes/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- NF-E2-Related Factor 2/metabolism
- Neuroprotective Agents/pharmacology
- Phosphorylation/drug effects
- Piperazines/pharmacology
- Protein Kinase C-delta/metabolism
- Pyridines/pharmacology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT2A/metabolism
- Serotonin/metabolism
- Serotonin 5-HT1 Receptor Antagonists/pharmacology
- Time Factors
- Up-Regulation
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Affiliation(s)
- Hai-Quyen Tran
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Youngho Lee
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea.
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Akihiro Mouri
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Science, Toyoake, Aichi, 470-1192, Japan
| | - Kuniaki Saito
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Science, Toyoake, Aichi, 470-1192, Japan
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Science, Toyoake, Aichi, 470-1192, Japan
- Aino University, Ibaraki, 576-0012, Japan
- Japanese Drug Organization of Appropriate and Research, Nagoya, 468-0069, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea.
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Evaluating the abuse potential of psychedelic drugs as part of the safety pharmacology assessment for medical use in humans. Neuropharmacology 2018; 142:89-115. [PMID: 29427652 DOI: 10.1016/j.neuropharm.2018.01.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/07/2018] [Accepted: 01/31/2018] [Indexed: 11/21/2022]
Abstract
Psychedelics comprise drugs come from various pharmacological classes including 5-HT2A agonists, indirect 5-HT agonists, e.g., MDMA, NMDA antagonists and κ-opioid receptor agonists. There is resurgence in developing psychedelics to treat psychiatric disorders with high unmet clinical need. Many, but not all, psychedelics are schedule 1 controlled drugs (CDs), i.e., no approved medical use. For existing psychedelics in development, regulatory approval will require a move from schedule 1 to a CD schedule for drugs with medical use, i.e., schedules 2-5. Although abuse of the psychedelics is well documented, a systematic preclinical and clinical evaluation of the risks they pose in a medical-use setting does not exist. We describe the non-clinical tests required for a regulatory evaluation of abuse/dependence risks, i.e., drug-discrimination, intravenous self-administration and physical dependence liability. A synopsis of the existing data for the various types of psychedelics is provided and we describe our findings with psychedelic drugs in these models. FDA recently issued its guidance on abuse/dependence evaluation of drug-candidates (CDER/FDA, 2017). We critically review the guidance, discuss the impact this document will have on non-clinical abuse/dependence testing, and offer advice on how non-clinical abuse/dependence experiments can be designed to meet not only the expectations of FDA, but also other regulatory agencies. Finally, we offer views on how these non-clinical tests can be refined to provide more meaningful information to aid the assessment of the risks posed by CNS drug-candidates for abuse and physical dependence. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.
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Young MB, Norrholm SD, Khoury LM, Jovanovic T, Rauch SAM, Reiff CM, Dunlop BW, Rothbaum BO, Howell LL. Inhibition of serotonin transporters disrupts the enhancement of fear memory extinction by 3,4-methylenedioxymethamphetamine (MDMA). Psychopharmacology (Berl) 2017; 234:2883-2895. [PMID: 28741031 PMCID: PMC5693755 DOI: 10.1007/s00213-017-4684-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/24/2017] [Indexed: 12/23/2022]
Abstract
RATIONALE 3,4-Methylenedioxymethamphetamine (MDMA) persistently improves symptoms of post-traumatic stress disorder (PTSD) when combined with psychotherapy. Studies in rodents suggest that these effects can be attributed to enhancement of fear memory extinction. Therefore, MDMA may improve the effects of exposure-based therapy for PTSD, particularly in treatment-resistant patients. However, given MDMA's broad pharmacological profile, further investigation is warranted before moving to a complex clinical population. OBJECTIVES We aimed to inform clinical research by providing a translational model of MDMA's effect, and elucidating monoaminergic mechanisms through which MDMA enhances fear extinction. METHODS We explored the importance of monoamine transporters targeted by MDMA to fear memory extinction, as measured by reductions in conditioned freezing and fear-potentiated startle (FPS) in mice. Mice were treated with selective inhibitors of individual monoamine transporters prior to combined MDMA treatment and fear extinction training. RESULTS MDMA enhanced the lasting extinction of FPS. Acute and chronic treatment with a 5-HT transporter (5-HTT) inhibitor blocked MDMA's effect on fear memory extinction. Acute inhibition of dopamine (DA) and norepinephrine (NE) transporters had no effect. 5-HT release alone did not enhance extinction. Blockade of MDMA's effect by 5-HTT inhibition also downregulated 5-HT2A-mediated behavior, and 5-HT2A antagonism disrupted MDMA's effect on extinction. CONCLUSIONS We validate enhancement of fear memory extinction by MDMA in a translational behavioral model, and reveal the importance of 5-HTT and 5-HT2A receptors to this effect. These observations support future clinical research of MDMA as an adjunct to exposure therapy, and provide important pharmacological considerations for clinical use in a population frequently treated with 5-HTT inhibitors.
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Affiliation(s)
- Matthew B Young
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA
| | - Seth D Norrholm
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA
- Atlanta VA Medical Center, Mental Health Service Line, Decatur, GA, USA
| | | | - Tanja Jovanovic
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA
- Atlanta VA Medical Center, Mental Health Service Line, Decatur, GA, USA
| | - Sheila A M Rauch
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA
- Atlanta VA Medical Center, Mental Health Service Line, Decatur, GA, USA
| | - Collin M Reiff
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA
| | - Boadie W Dunlop
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA
| | - Barbara O Rothbaum
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA
| | - Leonard L Howell
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 954 Gatewood Rd NE #2101, Atlanta, GA, 30329, USA.
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10
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5-HT2A and mGlu2/3 receptor interactions: on their relevance to cognitive function and psychosis. Behav Pharmacol 2016; 27:1-11. [PMID: 26292187 DOI: 10.1097/fbp.0000000000000183] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Serotonin [5-hydroxytryptamine (5-HT)] and glutamate have both been implicated in the pathophysiology of neuropsychiatric disorders but also in the mechanism of antipsychotic and hallucinogenic drug actions. Furthermore, close antagonistic interactions between 5-HT2A and metabotropic glutamate (mGlu)2/3 receptors have been established over the last decades on the basis of numerous electrophysiological, biochemical, and behavioral studies. Besides synaptic mechanisms, more recent findings suggested that heterodimeric 5-HT2A-mGlu2 receptor complexes in the prefrontal cortex may account for the functional crosstalk between these two receptor subtypes. In this review, we focus on in-vitro and in-vivo studies documenting the important relationship between 5-HT2A and mGlu2/3 receptors, with relevance to both normal behavioral function and psychosis.
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11
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Abstract
Psychedelics (serotonergic hallucinogens) are powerful psychoactive substances that alter perception and mood and affect numerous cognitive processes. They are generally considered physiologically safe and do not lead to dependence or addiction. Their origin predates written history, and they were employed by early cultures in many sociocultural and ritual contexts. After the virtually contemporaneous discovery of (5R,8R)-(+)-lysergic acid-N,N-diethylamide (LSD)-25 and the identification of serotonin in the brain, early research focused intensively on the possibility that LSD and other psychedelics had a serotonergic basis for their action. Today there is a consensus that psychedelics are agonists or partial agonists at brain serotonin 5-hydroxytryptamine 2A receptors, with particular importance on those expressed on apical dendrites of neocortical pyramidal cells in layer V. Several useful rodent models have been developed over the years to help unravel the neurochemical correlates of serotonin 5-hydroxytryptamine 2A receptor activation in the brain, and a variety of imaging techniques have been employed to identify key brain areas that are directly affected by psychedelics. Recent and exciting developments in the field have occurred in clinical research, where several double-blind placebo-controlled phase 2 studies of psilocybin-assisted psychotherapy in patients with cancer-related psychosocial distress have demonstrated unprecedented positive relief of anxiety and depression. Two small pilot studies of psilocybin-assisted psychotherapy also have shown positive benefit in treating both alcohol and nicotine addiction. Recently, blood oxygen level-dependent functional magnetic resonance imaging and magnetoencephalography have been employed for in vivo brain imaging in humans after administration of a psychedelic, and results indicate that intravenously administered psilocybin and LSD produce decreases in oscillatory power in areas of the brain's default mode network.
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Affiliation(s)
- David E Nichols
- Eschelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina
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12
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Puzerey PA, Kodama NX, Galán RF. Abnormal cell-intrinsic and network excitability in the neocortex of serotonin-deficient Pet-1 knockout mice. J Neurophysiol 2015; 115:813-25. [PMID: 26609119 DOI: 10.1152/jn.00996.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 11/24/2015] [Indexed: 12/18/2022] Open
Abstract
Neurons originating from the raphe nuclei of the brain stem are the exclusive source of serotonin (5-HT) to the cortex. Their serotonergic phenotype is specified by the transcriptional regulator Pet-1, which is also necessary for maintaining their neurotransmitter identity across development. Transgenic mice in which Pet-1 is genetically ablated (Pet-1(-/-)) show a dramatic reduction (∼80%) in forebrain 5-HT levels, yet no investigations have been carried out to assess the impact of such severe 5-HT depletion on the function of target cortical neurons. Using whole cell patch-clamp methods, two-dimensional (2D) multielectrode arrays (MEAs), 3D morphological neuronal reconstructions, and animal behavior, we investigated the impact of 5-HT depletion on cortical cell-intrinsic and network excitability. We found significant changes in several parameters of cell-intrinsic excitability in cortical pyramidal cells (PCs) as well as an increase in spontaneous synaptic excitation through 5-HT3 receptors. These changes are associated with increased local network excitability and oscillatory activity in a 5-HT2 receptor-dependent manner, consistent with previously reported hypersensitivity of cortical 5-HT2 receptors. PC morphology was also altered, with a significant reduction in dendritic complexity that may possibly act as a compensatory mechanism for increased excitability. Consistent with this interpretation, when we carried out experiments with convulsant-induced seizures to asses cortical excitability in vivo, we observed no significant differences in seizure parameters between wild-type and Pet-1(-/-) mice. Moreover, MEA recordings of propagating field potentials showed diminished propagation of activity across the cortical sheath. Together these findings reveal novel functional changes in neuronal and cortical excitability in mice lacking Pet-1.
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Affiliation(s)
- Pavel A Puzerey
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Nathan X Kodama
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Roberto F Galán
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
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13
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Nichols DE, Sassano MF, Halberstadt AL, Klein LM, Brandt SD, Elliott SP, Fiedler WJ. N-Benzyl-5-methoxytryptamines as Potent Serotonin 5-HT2 Receptor Family Agonists and Comparison with a Series of Phenethylamine Analogues. ACS Chem Neurosci 2015; 6:1165-75. [PMID: 25547199 PMCID: PMC4505863 DOI: 10.1021/cn500292d] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Indexed: 11/28/2022] Open
Abstract
A series of N-benzylated-5-methoxytryptamine analogues was prepared and investigated, with special emphasis on substituents in the meta position of the benzyl group. A parallel series of several N-benzylated analogues of 2,5-dimethoxy-4-iodophenethylamine (2C-I) also was included for comparison of the two major templates (i.e., tryptamine and phenethylamine). A broad affinity screen at serotonin receptors showed that most of the compounds had the highest affinity at the 5-HT2 family receptors. Substitution at the para position of the benzyl group resulted in reduced affinity, whereas substitution in either the ortho or the meta position enhanced affinity. In general, introduction of a large lipophilic group improved affinity, whereas functional activity often followed the opposite trend. Tests of the compounds for functional activity utilized intracellular Ca(2+) mobilization. Function was measured at the human 5-HT2A, 5-HT2B, and 5-HT2C receptors, as well as at the rat 5-HT2A and 5-HT2C receptors. There was no general correlation between affinity and function. Several of the tryptamine congeners were very potent functionally (EC50 values from 7.6 to 63 nM), but most were partial agonists. Tests in the mouse head twitch assay revealed that many of the compounds induced the head twitch and that there was a significant correlation between this behavior and functional potency at the rat 5-HT2A receptor.
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Affiliation(s)
- David E. Nichols
- Division
of Chemical Biology and Medicinal Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - M. Flori Sassano
- Division
of Chemical Biology and Medicinal Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Adam L. Halberstadt
- Department of Psychiatry, and Department of Neurosciences, University of California San Diego, La Jolla, California 92093, United States
| | - Landon M. Klein
- Department of Psychiatry, and Department of Neurosciences, University of California San Diego, La Jolla, California 92093, United States
| | - Simon D. Brandt
- School
of Pharmacy and Biomolecular Sciences, Liverpool
John Moores University, Byrom Street, Liverpool L3 3AF, U.K.
| | - Simon P. Elliott
- ROAR Forensics, Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire WR14 3SZ, U.K.
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14
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Anastasio NC, Stutz SJ, Fink LHL, Swinford-Jackson SE, Sears RM, DiLeone RJ, Rice KC, Moeller FG, Cunningham KA. Serotonin (5-HT) 5-HT2A Receptor (5-HT2AR):5-HT2CR Imbalance in Medial Prefrontal Cortex Associates with Motor Impulsivity. ACS Chem Neurosci 2015; 6:1248-58. [PMID: 26120876 DOI: 10.1021/acschemneuro.5b00094] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A feature of multiple neuropsychiatric disorders is motor impulsivity. Recent studies have implicated serotonin (5-HT) systems in medial prefrontal cortex (mPFC) in mediating individual differences in motor impulsivity, notably the 5-HT2AR receptor (5-HT2AR) and 5-HT2CR. We investigated the hypothesis that differences in the ratio of 5-HT2AR:5-HT2CR protein expression in mPFC would predict the individual level of motor impulsivity and that the engineered loss of the 5-HT2CR would result in high motor impulsivity concomitant with elevated 5-HT2AR expression and pharmacological sensitivity to the selective 5-HT2AR antagonist M100907. High and low impulsive rats were identified in a 1-choice serial reaction time task. Native protein levels of the 5-HT2AR and the 5-HT2CR predicted the intensity of motor impulsivity and the 5-HT2AR:5-HT2CR ratio in mPFC positively correlated with levels of premature responses in individual outbred rats. The possibility that the 5-HT2AR and 5-HT2CR act in concert to control motor impulsivity is supported by the observation that high phenotypic motor impulsivity associated with a diminished mPFC synaptosomal 5-HT2AR:5-HT2CR protein:protein interaction. Knockdown of mPFC 5-HT2CR resulted in increased motor impulsivity and triggered a functional disruption of the local 5-HT2AR:5-HT2CR balance as evidenced by a compensatory upregulation of 5-HT2AR protein expression and a leftward shift in the potency of M100907 to suppress impulsive behavior. We infer that there is an interactive relationship between the mPFC 5-HT2AR and 5-HT2CR, and that a 5-HT2AR:5-HT2CR imbalance may be a functionally relevant mechanism underlying motor impulsivity.
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Affiliation(s)
| | | | | | | | - Robert M. Sears
- Department
of Psychiatry, Yale University, New Haven, Connecticut 06520, United States
| | - Ralph J. DiLeone
- Department
of Psychiatry, Yale University, New Haven, Connecticut 06520, United States
| | - Kenner C. Rice
- Chemical
Biology Research Branch, National Institute on Drug Abuse, DHHS/NIH/NIDA, Bethesda, Maryland 20892, United States
| | - F. Gerard Moeller
- Department
of Psychiatry, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
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15
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Rangel-Barajas C, Malik M, Mach RH, Luedtke RR. Pharmacological modulation of abnormal involuntary DOI-induced head twitch response movements in male DBA/2J mice: II. Effects of D3 dopamine receptor selective compounds. Neuropharmacology 2015; 93:179-90. [PMID: 25698528 DOI: 10.1016/j.neuropharm.2014.10.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 12/27/2022]
Abstract
We recently reported on the characterization of the hallucinogen 2,5-dimethoxy-4-methylamphetamine's (DOI) ability to elicit a head twitch response (HTR) in DBA/2J mice and the ability of D2 vs. D3 dopamine receptor selective compounds to modulate that response. For these studies, the ability of D3 vs. D2 dopamine receptor selective compounds to attenuate the DOI-dependent HTR was examined. WC 10, a D3 dopamine receptor weak partial agonist with 40-fold binding selectivity for D3 vs. D2 dopamine receptors, produced a dose-dependent decrease in the DOI-induced HTR (IC50 = 3.7 mg/kg). WC 44, a D3 receptor selective full agonist, also inhibited the DOI-induced HTR (IC50 = 5.1 mg/kg). The effect of two D3 receptor selective partial agonists, LAX-4-136 and WW-III-55, were also evaluated. These analogs exhibit 150-fold and 800-fold D3 vs. D2 binding selectivity, respectively. Both compounds inhibited the HTR with similar potency but with different maximum efficacies. At 10 mg/kg WW-III-55 inhibited the HTR by 95%, while LAX-4-136 administration resulted in a 50% reduction. In addition, DOI (5 mg/kg) was administered at various times after LAX-4-136 or WW-III-55 administration to compare the duration of action. The homopiperazine analog LAX-4-136 exhibited greater stability. An assessment of our test compounds on motor performance and coordination was performed using a rotarod test. None of the D3 dopamine receptor selective compounds significantly altered latency to fall, suggesting that these compounds a) did not attenuate the DOI-dependent HTR due to sedative or adverse motor effects and b) may have antipsychotic/antihallucinogenic activity.
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Affiliation(s)
- Claudia Rangel-Barajas
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Maninder Malik
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Robert H Mach
- Radiochemistry Laboratory, Neurology Department, University of Pennsylvania School of Medicine, Chemistry Building, 231 S. 34th Street, Philadelphia, PA 19104, USA
| | - Robert R Luedtke
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA.
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16
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Sundqvist M, Lundahl A, Någård MB, Bredberg U, Gennemark P. Quantifying and Communicating Uncertainty in Preclinical Human Dose-Prediction. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2015. [PMID: 26225248 PMCID: PMC4429578 DOI: 10.1002/psp4.32] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Human dose-prediction is fundamental for ranking lead-optimization compounds in drug discovery and to inform design of early clinical trials. This tutorial describes how uncertainty in such predictions can be quantified and efficiently communicated to facilitate decision-making. Using three drug-discovery case studies, we show how several uncertain pieces of input information can be integrated into one single uncomplicated plot with key predictions, including their uncertainties, for many compounds or for many scenarios, or both.
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Affiliation(s)
- M Sundqvist
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - A Lundahl
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - M B Någård
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - U Bredberg
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
| | - P Gennemark
- CVMD iMed DMPK, AstraZeneca R&D SE-431, 83, Mölndal, Sweden
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17
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Buchborn T, Schröder H, Dieterich DC, Grecksch G, Höllt V. Tolerance to LSD and DOB induced shaking behaviour: differential adaptations of frontocortical 5-HT(2A) and glutamate receptor binding sites. Behav Brain Res 2015; 281:62-8. [PMID: 25513973 DOI: 10.1016/j.bbr.2014.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 12/04/2014] [Accepted: 12/06/2014] [Indexed: 12/20/2022]
Abstract
Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD) and dimethoxy-bromoamphetamine (DOB), provoke stereotype-like shaking behaviour in rodents, which is hypothesised to engage frontocortical glutamate receptor activation secondary to serotonin2A (5-HT2A) related glutamate release. Challenging this hypothesis, we here investigate whether tolerance to LSD and DOB correlates with frontocortical adaptations of 5-HT2A and/or overall-glutamate binding sites. LSD and DOB (0.025 and 0.25 mg/kg, i.p.) induce a ketanserin-sensitive (0.5 mg/kg, i.p., 30-min pretreatment) increase in shaking behaviour (including head twitches and wet dog shakes), which with repeated application (7× in 4 ds) is undermined by tolerance. Tolerance to DOB, as indexed by DOB-sensitive [(3)H]spiroperidol and DOB induced [(35)S]GTP-gamma-S binding, is accompanied by a frontocortical decrease in 5-HT2A binding sites and 5-HT2 signalling, respectively; glutamate-sensitive [(3)H]glutamate binding sites, in contrast, remain unchanged. As to LSD, 5-HT2 signalling and 5-HT2A binding, respectively, are not or only marginally affected, yet [(3)H]glutamate binding is significantly decreased. Correlation analysis interrelates tolerance to DOB to the reduced 5-HT2A (r=.80) as well as the unchanged [(3)H]glutamate binding sites (r=.84); tolerance to LSD, as opposed, shares variance with the reduction in [(3)H]glutamate binding sites only (r=.86). Given that DOB and LSD both induce tolerance, one correlating with 5-HT2A, the other with glutamate receptor adaptations, it might be inferred that tolerance can arise at either level. That is, if a hallucinogen (like LSD in our study) fails to induce 5-HT2A (down-)regulation, glutamate receptors (activated postsynaptic to 5-HT2A related glutamate release) might instead adapt and thus prevent further overstimulation of the cortex.
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Affiliation(s)
- Tobias Buchborn
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Helmut Schröder
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Daniela C Dieterich
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.
| | - Gisela Grecksch
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Volker Höllt
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
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18
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Halberstadt AL. Recent advances in the neuropsychopharmacology of serotonergic hallucinogens. Behav Brain Res 2015; 277:99-120. [PMID: 25036425 PMCID: PMC4642895 DOI: 10.1016/j.bbr.2014.07.016] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 12/12/2022]
Abstract
Serotonergic hallucinogens, such as (+)-lysergic acid diethylamide, psilocybin, and mescaline, are somewhat enigmatic substances. Although these drugs are derived from multiple chemical families, they all produce remarkably similar effects in animals and humans, and they show cross-tolerance. This article reviews the evidence demonstrating the serotonin 5-HT2A receptor is the primary site of hallucinogen action. The 5-HT2A receptor is responsible for mediating the effects of hallucinogens in human subjects, as well as in animal behavioral paradigms such as drug discrimination, head twitch response, prepulse inhibition of startle, exploratory behavior, and interval timing. Many recent clinical trials have yielded important new findings regarding the psychopharmacology of these substances. Furthermore, the use of modern imaging and electrophysiological techniques is beginning to help unravel how hallucinogens work in the brain. Evidence is also emerging that hallucinogens may possess therapeutic efficacy.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States.
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19
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Smith DA, Bailey JM, Williams D, Fantegrossi WE. Tolerance and cross-tolerance to head twitch behavior elicited by phenethylamine- and tryptamine-derived hallucinogens in mice. J Pharmacol Exp Ther 2014; 351:485-91. [PMID: 25271256 DOI: 10.1124/jpet.114.219337] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The serotonin 5-hydroxytryptamine 2A (5-HT2A) receptor is a potential therapeutic target to a host of neuropsychiatric conditions, but agonist actions at this site are linked to abuse-related hallucinogenic effects that may limit therapeutic efficacy of chronic drug administration. Tolerance to some effects of hallucinogens has been observed in humans and laboratory animals, but the understanding of tolerance and cross-tolerance between distinct structural classes of hallucinogens is limited. Here, we used the drug-elicited head twitch response (HTR) in mice to assess the development of tolerance and cross-tolerance with two phenethylamine-derived [DOI (2,5-dimethoxy-4-iodoamphetamine) and 2C-T-7 (2,5-dimethoxy-4-propylthiophenethylamine)] and two tryptamine-derived [DPT (N,N-dipropyltryptamine) and DIPT (N,N-diisopropyltryptamine)] drugs with agonist affinity for 5-HT2A receptors. Tolerance developed to HTR elicited by daily DOI or 2C-T-7, but not to HTR elicited by DPT or DIPT. DOI-elicited tolerance was not surmountable with dose, and a similar insurmountable cross-tolerance was evident when DOI-tolerant mice were tested with various doses of 2C-T-7 or DPT. These studies suggest that the use of phenethylamine-derived hallucinogens as therapeutic agents may be limited not only by their abuse potential, but also by the rapid development of tolerance that would likely be maintained even if a patient were switched to a different 5-HT2A agonist medication from a distinct structural class. However, these experiments also imply that tryptamine-derived hallucinogens might have a reduced potential for tolerance development, compared with phenethylamine-derived 5-HT2A agonists, and might therefore be more suitable for chronic administration in a therapeutic context.
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Affiliation(s)
- Douglas A Smith
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (D.A.S.); and Interdisciplinary Biomedical Sciences Program (J.M.B., D.W.), Department of Pharmacology and Toxicology (W.E.F.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Jessica M Bailey
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (D.A.S.); and Interdisciplinary Biomedical Sciences Program (J.M.B., D.W.), Department of Pharmacology and Toxicology (W.E.F.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Diarria Williams
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (D.A.S.); and Interdisciplinary Biomedical Sciences Program (J.M.B., D.W.), Department of Pharmacology and Toxicology (W.E.F.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - William E Fantegrossi
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (D.A.S.); and Interdisciplinary Biomedical Sciences Program (J.M.B., D.W.), Department of Pharmacology and Toxicology (W.E.F.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
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20
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Puzerey PA, Decker MJ, Galán RF. Elevated serotonergic signaling amplifies synaptic noise and facilitates the emergence of epileptiform network oscillations. J Neurophysiol 2014; 112:2357-73. [PMID: 25122717 DOI: 10.1152/jn.00031.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serotonin fibers densely innervate the cortical sheath to regulate neuronal excitability, but its role in shaping network dynamics remains undetermined. We show that serotonin provides an excitatory tone to cortical neurons in the form of spontaneous synaptic noise through 5-HT3 receptors, which is persistent and can be augmented using fluoxetine, a selective serotonin re-uptake inhibitor. Augmented serotonin signaling also increases cortical network activity by enhancing synaptic excitation through activation of 5-HT2 receptors. This in turn facilitates the emergence of epileptiform network oscillations (10-16 Hz) known as fast runs. A computational model of cortical dynamics demonstrates that these two combined mechanisms, increased background synaptic noise and enhanced synaptic excitation, are sufficient to replicate the emergence fast runs and their statistics. Consistent with these findings, we show that blocking 5-HT2 receptors in vivo significantly raises the threshold for convulsant-induced seizures.
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Affiliation(s)
- Pavel A Puzerey
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - Michael J Decker
- School of Nursing, Case Western Reserve University, Cleveland, Ohio
| | - Roberto F Galán
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
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Rangel-Barajas C, Malik M, Vangveravong S, Mach RH, Luedtke RR. Pharmacological modulation of abnormal involuntary DOI-induced head twitch response in male DBA/2J mice: I. Effects of D2/D3 and D2 dopamine receptor selective compounds. Neuropharmacology 2014; 83:18-27. [PMID: 24680675 DOI: 10.1016/j.neuropharm.2014.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 03/05/2014] [Accepted: 03/08/2014] [Indexed: 12/26/2022]
Abstract
Because of the complexity and heterogeneity of human neuropsychiatric disorders, it has been difficult to identify animal models that mimic the symptoms of these neuropathologies and can be used to screen for antipsychotic agents. For this study we selected the murine 5HT2A/2C receptor agonist-induced head twitch response (HTR) induced by the administration of 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), which has been proposed as an animal model of symptoms associated with a variety of behavioral and psychiatric conditions. We investigated the DOI-induced HTR in male DBA/2J mice using a panel of D2-like (D2, D3 and D4) and D2 dopamine receptor selective compounds. When DBA/2J mice were administered a daily dose of DOI (5 mg/kg), tolerance to the DOI occurs. However, administrations of the same dose of DOI every other day (48 h) or on a weekly basis did not lead to tolerance and the ability to induce tolerance after daily administration of DOI remains intact after repeated weekly administration of DOI. Subsequently, a panel of D2-like dopamine receptor antagonists was found to effectively inhibit the DOI-induced HTR in DBA/2J mice. However, the benzamide eticlopride, which is a high affinity D2-like antagonist, was a notable exception. SV 293, SV-III-130s and N-methylbenperidol, which exhibit a high affinity for D2 versus the D3 dopamine receptor subtypes (60- to 100-fold binding selectivity), were also found to inhibit the HTR in DBA/2J mice. This observation suggests a functional interaction between dopaminergic and serotonergic systems through D2 dopamine receptors and the 5-HT2A serotonin receptors in vivo.
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Affiliation(s)
- Claudia Rangel-Barajas
- University of North Texas Health Science Center, the Department of Pharmacology and Neuroscience, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Maninder Malik
- University of North Texas Health Science Center, the Department of Pharmacology and Neuroscience, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Suwanna Vangveravong
- Division of Radiological Sciences, Washington University School of Medicine, Mallinckrodt Institute of Radiology, 510 S. Kingshighway, St. Louis, MO 63110, USA
| | - Robert H Mach
- Radiochemistry Laboratory, Neurology Department, University of Pennsylvania School of Medicine, Chemistry Building, 231 S. 34th Street, Philadelphia, PA 19104, USA
| | - Robert R Luedtke
- University of North Texas Health Science Center, the Department of Pharmacology and Neuroscience, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA.
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Canal CE, Cordova-Sintjago T, Liu Y, Kim MS, Morgan D, Booth RG. Molecular pharmacology and ligand docking studies reveal a single amino acid difference between mouse and human serotonin 5-HT2A receptors that impacts behavioral translation of novel 4-phenyl-2-dimethylaminotetralin ligands. J Pharmacol Exp Ther 2013; 347:705-16. [PMID: 24080681 DOI: 10.1124/jpet.113.208637] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
During translational studies to develop 4-phenyl-2-dimethylaminotetralin (PAT) compounds for neuropsychiatric disorders, the (2R,4S)-trans-(+)- and (2S,4R)-trans-(-)-enantiomers of the analog 6-hydroxy-7-chloro-PAT (6-OH-7-Cl-PAT) demonstrated unusual pharmacology at serotonin (5-HT) 5-HT2 G protein-coupled receptors (GPCRs). The enantiomers had similar affinities (Ki) at human (h) 5-HT2A receptors (≈ 70 nM). In an in vivo mouse model of 5-HT2A receptor activation [(±)-(2,5)-dimethoxy-4-iodoamphetamine (DOI)-elicited head twitch], however, (-)-6-OH-7-Cl-PAT was about 5-fold more potent than the (+)-enantiomer at attenuating the DOI-elicited response. It was discovered that (+)-6-OH-7-Cl-PAT (only) had ≈ 40-fold-lower affinity at mouse (m) compared with h5-HT2A receptors. Molecular modeling and computational ligand docking studies indicated that the 6-OH moiety of (+)- but not (-)-6-OH-7-Cl-PAT could form a hydrogen bond with serine residue 5.46 of the h5-HT2A receptor. The m5-HT2A as well as m5-HT2B, h5-HT2B, m5-HT2C, and h5-HT2C receptors have alanine at position 5.46, obviating this interaction; (+)-6-OH-7-Cl-PAT also showed ≈ 50-fold lower affinity than (-)-6-OH-7-Cl-PAT at m5-HT2C and h5-HT2C receptors. Mutagenesis studies confirmed that 5-HT2A S5.46 is critical for (+)- but not (-)-6-OH-7-Cl-PAT binding, as well as function. The (+)-6-OH-7-Cl-PAT enantiomer showed partial agonist effects at h5-HT2A wild-type (WT) and m5-HT2A A5.46S point-mutated receptors but did not activate m5-HT2A WT and h5-HT2A S5.46A point-mutated receptors, or h5-HT2B, h5-HT2C, and m5-HT2C receptors; (-)-6-OH-7-Cl-PAT did not activate any of the 5-HT2 receptors. Experiments also included the (2R,4S)-trans-(+)- and (2S,4R)-trans-(-)-enantiomers of 6-methoxy-7-chloro-PAT to validate hydrogen bonding interactions proposed for the corresponding 6-OH analogs. Results indicate that PAT ligand three-dimensional structure impacts target receptor binding and translational outcomes, supporting the hypothesis that GPCR ligand structure governs orthosteric binding pocket molecular determinants and resulting pharmacology.
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Affiliation(s)
- Clinton E Canal
- Center for Drug Discovery (C.E.C., T.C.-S., Y.L., R.G.B.), Department of Pharmaceutical Sciences (C.E.C., T.C.-S., Y.L., R.G.B.), and Department of Chemistry and Chemical Biology (R.G.B.), Northeastern University, Boston, Massachusetts; and Department of Medicinal Chemistry (M.S.K., T.C.-S.) and Department of Psychiatry (D.M.), University of Florida, Gainesville, Florida
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Dougherty JP, Oristaglio J. Chronic treatment with the serotonin 2A/2C receptor antagonist SR 46349B enhances the retention and efficiency of rule-guided behavior in mice. Neurobiol Learn Mem 2013; 103:50-63. [PMID: 23587729 DOI: 10.1016/j.nlm.2013.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 03/13/2013] [Accepted: 04/04/2013] [Indexed: 01/21/2023]
Abstract
Animal studies have established that drugs activating the serotonin 2A (5-HT2A) receptor can enhance learning and memory in a variety of classical and operant conditioning tasks. Unfortunately, long-term agonism typically results in receptor downregulation, which can negate such nootropic effects. Conversely, chronic antagonism can act to increase receptor density, an adaptation which, in principle, should enhance cognition in a manner similar to acute agonism. In this study, we questioned whether chronic treatment with the 5-HT2A receptor antagonist, SR 46349B, a drug known to increase 5-HT2A receptor density in vivo, would improve cognitive performance in normal mice. To address this question, we administered SR 46349B to mice for 4 days following initial training on a simple rule-based reward acquisition task. We subsequently tested their recall of this task and, finally, their ability to adapt to a reversal in reward contingency (reversal learning). For comparison, two additional groups were treated with the 5-HT2A/2C receptor agonist, DOI, which downregulates the 5-HT2A receptor. SR 46349B improved retention of the previously-learned task but did not affect reversal learning. Subjects treated with SR 46349B also completed trials faster and with greater motor efficiency than vehicle- or DOI-treated subjects. We hypothesize that long-term drug treatments resulting in 5-HT2A receptor up-regulation may be useful in enhancing recall of learned behaviors and, thus, may have potential for treating cognitive impairment associated with neurodegenerative disorders.
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Affiliation(s)
- John P Dougherty
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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Guimarães dos Santos R. Safety and Side Effects of Ayahuasca in Humans—An Overview Focusing on Developmental Toxicology. J Psychoactive Drugs 2013; 45:68-78. [DOI: 10.1080/02791072.2013.763564] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Support for 5-HT2C receptor functional selectivity in vivo utilizing structurally diverse, selective 5-HT2C receptor ligands and the 2,5-dimethoxy-4-iodoamphetamine elicited head-twitch response model. Neuropharmacology 2013; 70:112-21. [PMID: 23353901 DOI: 10.1016/j.neuropharm.2013.01.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 01/03/2013] [Accepted: 01/10/2013] [Indexed: 11/22/2022]
Abstract
There are seemingly conflicting data in the literature regarding the role of serotonin (5-HT) 5-HT2C receptors in the mouse head-twitch response (HTR) elicited by the hallucinogenic 5-HT2A/2B/2C receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI). Namely, both 5-HT2C receptor agonists and antagonists, regarding 5-HT2C receptor-mediated Gq-phospholipase C (PLC) signaling, reportedly attenuate the HTR response. The present experiments tested the hypothesis that both classes of 5-HT2C receptor compounds could attenuate the DOI-elicited-HTR in a single strain of mice, C57Bl/6J. The expected results were considered in accordance with ligand functional selectivity. Commercially-available 5-HT2C agonists (CP 809101, Ro 60-0175, WAY 161503, mCPP, and 1-methylpsilocin), novel 4-phenyl-2-N,N-dimethyl-aminotetralin (PAT)-type 5-HT2C agonists (with 5-HT2A/2B antagonist activity), and antagonists selective for 5-HT2A (M100907), 5-HT2C (SB-242084), and 5-HT2B/2C (SB-206553) receptors attenuated the DOI-elicited-HTR. In contrast, there were differential effects on locomotion across classes of compounds. The 5-HT2C agonists and M100907 decreased locomotion, SB-242084 increased locomotion, SB-206553 resulted in dose-dependent biphasic effects on locomotion, and the PATs did not alter locomotion. In vitro molecular pharmacology studies showed that 5-HT2C agonists potent for attenuating the DOI-elicited-HTR also reduced the efficacy of DOI to activate mouse 5-HT2C receptor-mediated PLC signaling in HEK cells. Although there were differences in affinities of a few compounds at mouse compared to human 5-HT2A or 5-HT2C receptors, all compounds tested retained their selectivity for either receptor, regardless of receptor species. Results indicate that 5-HT2C receptor agonists and antagonists attenuate the DOI-elicited-HTR in C57Bl/6J mice, and suggest that structurally diverse 5-HT2C ligands result in different 5-HT2C receptor signaling outcomes compared to DOI.
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Williams AA, Ingram WM, Levine S, Resnik J, Kamel CM, Lish JR, Elizalde DI, Janowski SA, Shoker J, Kozlenkov A, González-Maeso J, Gallitano AL. Reduced levels of serotonin 2A receptors underlie resistance of Egr3-deficient mice to locomotor suppression by clozapine. Neuropsychopharmacology 2012; 37:2285-98. [PMID: 22692564 PMCID: PMC3422493 DOI: 10.1038/npp.2012.81] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/06/2012] [Accepted: 04/26/2012] [Indexed: 02/06/2023]
Abstract
The immediate-early gene early growth response 3 (Egr3) is associated with schizophrenia and expressed at reduced levels in postmortem patients' brains. We have previously reported that Egr3-deficient (Egr3(-/-)) mice display reduced sensitivity to the sedating effects of clozapine compared with wild-type (WT) littermates, paralleling the heightened tolerance of schizophrenia patients to antipsychotic side effects. In this study, we have used a pharmacological dissection approach to identify a neurotransmitter receptor defect in Egr3(-/-) mice that may mediate their resistance to the locomotor suppressive effects of clozapine. We report that this response is specific to second-generation antipsychotic agents (SGAs), as first-generation medications suppress the locomotor activity of Egr3(-/-) and WT mice to a similar degree. Further, in contrast to the leading theory that sedation by clozapine results from anti-histaminergic effects, we show that H1 histamine receptors are not responsible for this effect in C57BL/6 mice. Instead, selective serotonin 2A receptor (5HT(2A)R) antagonists ketanserin and MDL-11939 replicate the effect of SGAs, repressing the activity in WT mice at a dosage that fails to suppress the activity of Egr3(-/-) mice. Radioligand binding revealed nearly 70% reduction in 5HT(2A)R expression in the prefrontal cortex of Egr3(-/-) mice compared with controls. Egr3(-/-) mice also exhibit a decreased head-twitch response to 5HT(2A)R agonist 1-(2,5-dimethoxy 4-iodophenyl)-2-amino propane (DOI). These findings provide a mechanism to explain the reduced sensitivity of Egr3(-/-) mice to the locomotor suppressive effects of SGAs, and suggest that 5HT(2A)Rs may also contribute to the sedating properties of these medications in humans. Moreover, as the deficit in cortical 5HT(2A)R in Egr3(-/-) mice aligns with numerous studies reporting decreased 5HT(2A)R levels in the brains of schizophrenia patients, and the gene encoding the 5HT(2A)R is itself a leading schizophrenia candidate gene, these findings suggest a potential mechanism by which putative dysfunction in EGR3 in humans may influence risk for schizophrenia.
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Affiliation(s)
| | - Wendy M Ingram
- Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley, CA, USA
| | - Sarah Levine
- University of Arizona College of Medicine—Tucson, Tucson, AZ, USA
| | - Jack Resnik
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Christy M Kamel
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - James R Lish
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Diana I Elizalde
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Scott A Janowski
- University of Arizona College of Medicine—Tucson, Tucson, AZ, USA
| | - Joseph Shoker
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Alexey Kozlenkov
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
| | - Javier González-Maeso
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Amelia L Gallitano
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
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Canal CE, Morgan D. Head-twitch response in rodents induced by the hallucinogen 2,5-dimethoxy-4-iodoamphetamine: a comprehensive history, a re-evaluation of mechanisms, and its utility as a model. Drug Test Anal 2012; 4:556-76. [PMID: 22517680 DOI: 10.1002/dta.1333] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/09/2012] [Accepted: 01/10/2012] [Indexed: 11/06/2022]
Abstract
Two primary animal models persist for assessing hallucinogenic potential of novel compounds and for examining the pharmacological and neurobiological substrates underlying the actions of classical hallucinogens, the two-lever drug discrimination procedure and the drug-induced head-twitch response (HTR) in rodents. The substituted amphetamine hallucinogen, serotonin 2 (5-HT(2) ) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI) has emerged as the most popular pharmacological tool used in HTR studies of hallucinogens. Synthesizing classic, recent, and relatively overlooked findings, addressing ostensibly conflicting observations, and considering contemporary theories in receptor and behavioural pharmacology, this review provides an up-to-date and comprehensive synopsis of DOI and the HTR model, from neural mechanisms to utility for understanding psychiatric diseases. Also presented is support for the argument that, although both the two-lever drug discrimination and the HTR models in rodents are useful for uncovering receptors, interacting proteins, intracellular signalling pathways, and neurochemical processes affected by DOI and related classical hallucinogens, results from both models suggest they are not reporting hallucinogenic experiences in animals.
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Affiliation(s)
- Clint E Canal
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
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Pharmacology of ayahuasca administered in two repeated doses. Psychopharmacology (Berl) 2012; 219:1039-53. [PMID: 21842159 DOI: 10.1007/s00213-011-2434-x] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/27/2011] [Indexed: 10/17/2022]
Abstract
RATIONALE Ayahuasca is an Amazonian tea containing the natural psychedelic 5-HT(2A/2C/1A) agonist N,N-dimethyltryptamine (DMT). It is used in ceremonial contexts for its visionary properties. The human pharmacology of ayahuasca has been well characterized following its administration in single doses. OBJECTIVES To evaluate the human pharmacology of ayahuasca in repeated doses and assess the potential occurrence of acute tolerance or sensitization. METHODS In a double-blind, crossover, placebo-controlled clinical trial, nine experienced psychedelic drug users received PO the two following treatment combinations at least 1 week apart: (a) a lactose placebo and then, 4 h later, an ayahuasca dose; and (b) two ayahuasca doses 4 h apart. All ayahuasca doses were freeze-dried Amazonian-sourced tea encapsulated to a standardized 0.75 mg DMT/kg bodyweight. Subjective, neurophysiological, cardiovascular, autonomic, neuroendocrine, and cell immunity measures were obtained before and at regular time intervals until 12 h after first dose administration. RESULTS DMT plasma concentrations, scores in subjective and neurophysiological variables, and serum prolactin and cortisol were significantly higher after two consecutive doses. When effects were standardized by plasma DMT concentrations, no differences were observed for subjective, neurophysiological, autonomic, or immunological effects. However, we observed a trend to reduced systolic blood pressure and heart rate, and a significant decrease for growth hormone (GH) after the second ayahuasca dose. CONCLUSIONS Whereas there was no clear-cut tolerance or sensitization in the psychological sphere or most physiological variables, a trend to lower cardiovascular activation was observed, together with significant tolerance to GH secretion.
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Abstract
A variety of serotonin (5-HT) receptors, especially 5-HT(2A), 5-HT(1A), 5-HT(6), 5-HT(7), and 5-HT(2C), have been postulated to contribute to the mechanism of action of atypical antipsychotic drugs (APDs), i.e., APDs which cause fewer extrapyramidal side effects (EPS) at clinically optimal doses, in contrast with typical APDs, which are more likely to cause EPS. This advantage, rarely disputed, has made such drugs the preferred treatment for schizophrenia and other indications for APDs. These 5-HT receptors are still of interest as components of novel multireceptor or stand-alone APDs, and potentially to remediate cognitive deficits in schizophrenia. Almost all currently available atypical APDs are 5-HT(2A) receptor inverse agonists, as well as dopamine (DA) D(2) receptor antagonists or partial agonists. Amisulpride, an exceptional atypical APD, has 5-HT(7) antagonism to complement its DA D(2/3) antagonism. Some atypical APDs are also 5-HT(1A) partial agonists, 5-HT(6), or 5-HT(7) antagonists, or some combination of the above. 5-HT(2C) antagonism has been found to contribute to the metabolic side effects of some atypical APDs, whereas 5-HT(2C) agonists have potential as stand-alone APDs and/or cognitive enhancers. This review will provide an update of current preclinical and clinical evidence for the role of these five 5-HT receptors in the actions of current APDs and for the development of novel psychotropic drugs.
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Affiliation(s)
- Herbert Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA.
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