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Serotonin Receptor 5-HT2A Regulates TrkB Receptor Function in Heteroreceptor Complexes. Cells 2022; 11:cells11152384. [PMID: 35954229 PMCID: PMC9368268 DOI: 10.3390/cells11152384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/22/2022] [Accepted: 07/29/2022] [Indexed: 02/04/2023] Open
Abstract
Serotonin receptor 5-HT2A and tropomyosin receptor kinase B (TrkB) strongly contribute to neuroplasticity regulation and are implicated in numerous neuronal disorders. Here, we demonstrate a physical interaction between 5-HT2A and TrkB in vitro and in vivo using co-immunoprecipitation and biophysical and biochemical approaches. Heterodimerization decreased TrkB autophosphorylation, preventing its activation with agonist 7,8-DHF, even with low 5-HT2A receptor expression. A blockade of 5-HT2A receptor with the preferential antagonist ketanserin prevented the receptor-mediated downregulation of TrkB phosphorylation without restoring the TrkB response to its agonist 7,8-DHF in vitro. In adult mice, intraperitoneal ketanserin injection increased basal TrkB phosphorylation in the frontal cortex and hippocampus, which is in accordance with our findings demonstrating the prevalence of 5-HT2A–TrkB heteroreceptor complexes in these brain regions. An expression analysis revealed strong developmental regulation of 5-HT2A and TrkB expressions in the cortex, hippocampus, and especially the striatum, demonstrating that the balance between TrkB and 5-HT2A may shift in certain brain regions during postnatal development. Our data reveal the functional role of 5-HT2A–TrkB receptor heterodimerization and suggest that the regulated expression of 5-HT2A and TrkB is a molecular mechanism for the brain-region-specific modulation of TrkB functions during development and under pathophysiological conditions.
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Gentile Polese A, Nigam S, Hurley LM. 5-HT1A Receptors Alter Temporal Responses to Broadband Vocalizations in the Mouse Inferior Colliculus Through Response Suppression. Front Neural Circuits 2021; 15:718348. [PMID: 34512276 PMCID: PMC8430226 DOI: 10.3389/fncir.2021.718348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/19/2021] [Indexed: 01/21/2023] Open
Abstract
Neuromodulatory systems may provide information on social context to auditory brain regions, but relatively few studies have assessed the effects of neuromodulation on auditory responses to acoustic social signals. To address this issue, we measured the influence of the serotonergic system on the responses of neurons in a mouse auditory midbrain nucleus, the inferior colliculus (IC), to vocal signals. Broadband vocalizations (BBVs) are human-audible signals produced by mice in distress as well as by female mice in opposite-sex interactions. The production of BBVs is context-dependent in that they are produced both at early stages of interactions as females physically reject males and at later stages as males mount females. Serotonin in the IC of males corresponds to these events, and is elevated more in males that experience less female rejection. We measured the responses of single IC neurons to five recorded examples of BBVs in anesthetized mice. We then locally activated the 5-HT1A receptor through iontophoretic application of 8-OH-DPAT. IC neurons showed little selectivity for different BBVs, but spike trains were characterized by local regions of high spike probability, which we called "response features." Response features varied across neurons and also across calls for individual neurons, ranging from 1 to 7 response features for responses of single neurons to single calls. 8-OH-DPAT suppressed spikes and also reduced the numbers of response features. The weakest response features were the most likely to disappear, suggestive of an "iceberg"-like effect in which activation of the 5-HT1A receptor suppressed weakly suprathreshold response features below the spiking threshold. Because serotonin in the IC is more likely to be elevated for mounting-associated BBVs than for rejection-associated BBVs, these effects of the 5-HT1A receptor could contribute to the differential auditory processing of BBVs in different behavioral subcontexts.
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Affiliation(s)
- Arianna Gentile Polese
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biology, Program in Neuroscience, Indiana University Bloomington, Bloomington, IN, United States
| | - Sunny Nigam
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Department of Physics, Indiana University Bloomington, Bloomington, IN, United States
| | - Laura M. Hurley
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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Alymov AA, Kapitsa IG, Voronina TA. Neurochemical Mechanisms of Pathogenesis and Pharmacological Correction of Autism Spectrum Disorders: Current Concepts and Prospects. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421020033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Neuropharmacological Analysis of the Antidepressant Action of 2-[3-Methyl-7-(Thietan-3-Yl)-1-Ethylxanth-8-YLTHIO] Acetic Acid Hydrazide. Pharm Chem J 2020. [DOI: 10.1007/s11094-020-02218-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Citalopram reduces glutamatergic synaptic transmission in the auditory cortex via activation of 5-HT1A receptors. Neuroreport 2020; 30:1316-1322. [PMID: 31714483 DOI: 10.1097/wnr.0000000000001366] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Serotonin modulates cognitive processes and is related to various psychiatric disorders, including major depression. Administration of citalopram reduces the amplitude of auditory evoked potentials in depressed people and animal models, suggesting that 5-HT has an inhibitory role. Here, we characterize the modulation of excitatory post-synaptic currents by application of either 5-HT or agonists of 5-HT1A and 5-HT2 receptors, or by endogenous 5-HT evoked by citalopram on pyramidal neurons from layer II/III of rat auditory cortex. We found that application of 5-HT concentration-dependently reduces excitatory post-synaptic currents amplitude without changing the paired-pulse ratio, suggesting a post-synaptic modulation. We observed that selective agonists of 5-HT1A and 5-HT2 receptors [8-OH-DPAT (10 µM) and DOI (10 µM), respectively] mimic the effect of 5-HT on the excitatory post-synaptic currents. Effect of 5-HT was entirely blocked by co-application of the antagonists NAN-190 (1 µM) and ritanserin (200 nM). Similarly, citalopram application (1 μM) reduced the amplitude of the evoked excitatory post-synaptic currents. Reduction in the magnitude of the excitatory post-synaptic currents by endogenous 5-HT was interpolated in the dose-response curve elicited by exogenous 5-HT, yielding that citalopram raised the extracellular 5-HT concentration to 823 nM. Effect of citalopram was blocked by the previous application of NAN-190 but not ritanserin, indicating that citalopram reduces glutamatergic synaptic transmission via 5-HT1A receptors in layer II/III of the auditory cortex. These results suggest that the local activity of 5-HT contributes to decrease in the basal excitability of the auditory cortex for enhancing the detection of external relevant acoustic signals.
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Gaucher Q, Yger P, Edeline JM. Increasing excitation versus decreasing inhibition in auditory cortex: consequences on the discrimination performance between communication sounds. J Physiol 2020; 598:3765-3785. [PMID: 32538485 DOI: 10.1113/jp279902] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/08/2020] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Enhancing cortical excitability can be achieved by either reducing intracortical inhibition or by enhancing intracortical excitation. Here we compare the consequences of reducing intracortical inhibition and of enhancing intracortical excitation on the processing of communication sounds in the primary auditory cortex. Local application of gabazine and of AMPA enlarged the spectrotemporal receptive fields and increased the responses to communication to the same extent. The Mutual Information (an index of the cortical neurons' ability to discriminate between natural sounds) was increased in both cases, as were the noise and signal correlations. Spike-timing reliability was only increased after gabazine application and post-excitation suppression was affected in the opposite way: it was increased when reducing the intracortical inhibition but was eliminated by enhancing the excitation. A computational model suggests that these results can be explained by an additive effect vs. a multiplicative effect ABSTRACT: The level of excitability of cortical circuits is often viewed as one of the critical factors controlling perceptive performance. In theory, enhancing cortical excitability can be achieved either by reducing inhibitory currents or by increasing excitatory currents. Here, we evaluated whether reducing inhibitory currents or increasing excitatory currents in auditory cortex similarly affects the neurons' ability to discriminate between communication sounds. We attenuated the inhibitory currents by application of gabazine (GBZ), and increased the excitatory currents by applying AMPA in the auditory cortex while testing frequency receptive fields and responses to communication sounds. GBZ and AMPA enlarged the receptive fields and increased the responses to communication sounds to the same extent. The spike-timing reliability of neuronal responses was largely increased when attenuating the intracortical inhibition but not after increasing the excitation. The discriminative abilities of cortical cells increased in both cases but this increase was more pronounced after attenuating the inhibition. The shape of the response to communication sounds was modified in the opposite direction: reducing inhibition increased post-excitation suppression whereas this suppression tended to disappear when increasing the excitation. A computational model indicates that the additive effect promoted by AMPA vs. the multiplicative effect of GBZ on neuronal responses, together with the dynamics of spontaneous cortical activity, can explain these differences. Thus, although apparently equivalent for increasing cortical excitability, acting on inhibition vs. on excitation impacts differently the cortical ability to discriminate natural stimuli, and only modulating inhibition changed efficiently the cortical representation of communication sounds.
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Affiliation(s)
- Quentin Gaucher
- Paris-Saclay Institute of Neurosciences (Neuro-PSI), Department Cognition and Behaviour, CNRS UMR 9197, Orsay Cedex, 91405, France.,Université Paris-Sud, Bâtiment 446, Orsay Cedex, 91405, France
| | - Pierre Yger
- Institut de la Vision, INSERM UMRS 968, UPMC UM 80, CNRS UMR 7210, Paris, France
| | - Jean-Marc Edeline
- Paris-Saclay Institute of Neurosciences (Neuro-PSI), Department Cognition and Behaviour, CNRS UMR 9197, Orsay Cedex, 91405, France.,Université Paris-Sud, Bâtiment 446, Orsay Cedex, 91405, France
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Keesom SM, Hurley LM. Silence, Solitude, and Serotonin: Neural Mechanisms Linking Hearing Loss and Social Isolation. Brain Sci 2020; 10:brainsci10060367. [PMID: 32545607 PMCID: PMC7349698 DOI: 10.3390/brainsci10060367] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/06/2020] [Accepted: 06/09/2020] [Indexed: 12/11/2022] Open
Abstract
For social animals that communicate acoustically, hearing loss and social isolation are factors that independently influence social behavior. In human subjects, hearing loss may also contribute to objective and subjective measures of social isolation. Although the behavioral relationship between hearing loss and social isolation is evident, there is little understanding of their interdependence at the level of neural systems. Separate lines of research have shown that social isolation and hearing loss independently target the serotonergic system in the rodent brain. These two factors affect both presynaptic and postsynaptic measures of serotonergic anatomy and function, highlighting the sensitivity of serotonergic pathways to both types of insult. The effects of deficits in both acoustic and social inputs are seen not only within the auditory system, but also in other brain regions, suggesting relatively extensive effects of these deficits on serotonergic regulatory systems. Serotonin plays a much-studied role in depression and anxiety, and may also influence several aspects of auditory cognition, including auditory attention and understanding speech in challenging listening conditions. These commonalities suggest that serotonergic pathways are worthy of further exploration as potential intervening mechanisms between the related conditions of hearing loss and social isolation, and the affective and cognitive dysfunctions that follow.
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Affiliation(s)
- Sarah M. Keesom
- Department of Biology, Utica College, Utica, NY 13502, USA
- Correspondence:
| | - Laura M. Hurley
- Center for the Integrative Study of Animal Behavior, Department of Biology, Indiana University, Bloomington, IN 47405, USA;
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Sizemore TR, Hurley LM, Dacks AM. Serotonergic modulation across sensory modalities. J Neurophysiol 2020; 123:2406-2425. [PMID: 32401124 PMCID: PMC7311732 DOI: 10.1152/jn.00034.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/04/2020] [Accepted: 05/12/2020] [Indexed: 12/24/2022] Open
Abstract
The serotonergic system has been widely studied across animal taxa and different functional networks. This modulatory system is therefore well positioned to compare the consequences of neuromodulation for sensory processing across species and modalities at multiple levels of sensory organization. Serotonergic neurons that innervate sensory networks often bidirectionally exchange information with these networks but also receive input representative of motor events or motivational state. This convergence of information supports serotonin's capacity for contextualizing sensory information according to the animal's physiological state and external events. At the level of sensory circuitry, serotonin can have variable effects due to differential projections across specific sensory subregions, as well as differential serotonin receptor type expression within those subregions. Functionally, this infrastructure may gate or filter sensory inputs to emphasize specific stimulus features or select among different streams of information. The near-ubiquitous presence of serotonin and other neuromodulators within sensory regions, coupled with their strong effects on stimulus representation, suggests that these signaling pathways should be considered integral components of sensory systems.
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Affiliation(s)
- Tyler R Sizemore
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Laura M Hurley
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, West Virginia
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia
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Pillai RLI, Bartlett EA, Ananth MR, Zhu C, Yang J, Hajcak G, Parsey RV, DeLorenzo C. Examining the underpinnings of loudness dependence of auditory evoked potentials with positron emission tomography. Neuroimage 2020; 213:116733. [PMID: 32169543 DOI: 10.1016/j.neuroimage.2020.116733] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 11/30/2022] Open
Abstract
Loudness dependence of auditory evoked potentials (LDAEP) has long been considered to reflect central basal serotonin transmission. However, the relationship between LDAEP and individual serotonin receptors and transporters has not been fully explored in humans and may involve other neurotransmitter systems. To examine LDAEP's relationship with the serotonin system, we performed PET using serotonin-1A (5-HT1A) imaging via [11C]CUMI-101 and serotonin transporter (5-HTT) imaging via [11C]DASB on a mixed sample of healthy controls (n = 4: 4 females, 0 males), patients with unipolar (MDD, n = 11: 4 females, 7 males) and bipolar depression (BD, n = 8: 4 females, 4 males). On these same participants, we also performed electroencephalography (EEG) within a week of PET scanning, using 1000 Hz tones of varying intensity to evoke LDAEP. We then evaluated the relationship between LDAEP and 5-HT1A or 5-HTT binding in both the raphe (5-HT1A)/midbrain (5-HTT) areas and in the temporal cortex. We found that LDAEP was significantly correlated with 5-HT1A positively and with 5-HTT negatively in the temporal cortex (p < 0.05), but not correlated with either in midbrain or raphe. In males only, exploratory analysis showed multiple regions in which LDAEP significantly correlated with 5-HT1A throughout the brain; we did not find this with 5-HTT. This multimodal study partially validates preclinical models of a serotonergic influence on LDAEP. Replication in larger samples is necessary to further clarify our understanding of the role of serotonin in perception of auditory tones.
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Affiliation(s)
| | - Elizabeth A Bartlett
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, United States
| | - Mala R Ananth
- Department of Psychiatry, Stony Brook University, United States
| | - Chencan Zhu
- Department of Applied Mathematics and Statistics, Stony Brook University, United States
| | - Jie Yang
- Department of Family, Population, and Preventive Medicine, Stony Brook University, United States
| | - Greg Hajcak
- Department of Biomedical Sciences and Psychology, Florida State University, United States
| | - Ramin V Parsey
- Department of Psychiatry, Stony Brook University, United States
| | - Christine DeLorenzo
- Department of Psychiatry, Stony Brook University, United States; Department of Biomedical Engineering, Stony Brook University, United States
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10
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Bourin M. Experimental Anxiety Model for Anxiety Disorders: Relevance to Drug Discovery. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1191:169-184. [DOI: 10.1007/978-981-32-9705-0_11] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Steinberg LJ, Underwood MD, Bakalian MJ, Kassir SA, Mann JJ, Arango V. 5-HT1A receptor, 5-HT2A receptor and serotonin transporter binding in the human auditory cortex in depression. J Psychiatry Neurosci 2019; 44:294-302. [PMID: 31120232 PMCID: PMC6710086 DOI: 10.1503/jpn.180190] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Serotonergic system abnormalities are implicated in many psychiatric disorders, including major depression. The temporal lobe receives a high density of serotonergic afferent projections, and responses in the primary auditory cortex to sound are modulated by serotonergic tone. However, the associations between changes in serotonergic tone, disease state and changes in auditory cortical function remain to be clarified. METHODS We quantified serotonin 1A (5-HT1A) receptor binding, serotonin 2A (5-HT2A) receptor binding, and serotonin transporter (SERT) binding in Brodmann areas (BA) 41/42, 22, 9 and 4 from postmortem brain sections of 40 psychiatrically healthy controls and 39 individuals who had a history of a major depressive episode (MDE). RESULTS There was 33% lower 5-HT2A receptor binding in BA 41/42 in individuals who had an MDE than in controls (p = 0.0069). Neither 5-HT1A nor SERT binding in BA 41/42 differed between individuals who had an MDE and controls. We also found 14% higher 5-HT1A receptor binding (p = 0.045) and 21% lower SERT binding in BA 9 of individuals who had an MDE (p = 0.045). LIMITATIONS The study was limited by the small number of postmortem brain samples including BA 41/42 available for binding assays and the large overlap between suicide and depression in the MDE sample. CONCLUSION Depression may be associated with altered serotonergic function in the auditory cortex involving the 5-HT2A receptor and is part of a wider view of the pathophysiology of mood disorders extending beyond psychopathology.
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Affiliation(s)
- Louisa J. Steinberg
- From the Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Bakalian, Kassir, Mann, Arango); the Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Mann, Arango); and the Department of Radiology, Columbia University, New York, NY, USA (Mann)
| | - Mark D. Underwood
- From the Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Bakalian, Kassir, Mann, Arango); the Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Mann, Arango); and the Department of Radiology, Columbia University, New York, NY, USA (Mann)
| | - Mihran J. Bakalian
- From the Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Bakalian, Kassir, Mann, Arango); the Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Mann, Arango); and the Department of Radiology, Columbia University, New York, NY, USA (Mann)
| | - Suham A. Kassir
- From the Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Bakalian, Kassir, Mann, Arango); the Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Mann, Arango); and the Department of Radiology, Columbia University, New York, NY, USA (Mann)
| | - J. John Mann
- From the Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Bakalian, Kassir, Mann, Arango); the Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Mann, Arango); and the Department of Radiology, Columbia University, New York, NY, USA (Mann)
| | - Victoria Arango
- From the Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Bakalian, Kassir, Mann, Arango); the Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, USA (Steinberg, Underwood, Mann, Arango); and the Department of Radiology, Columbia University, New York, NY, USA (Mann)
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Huang M, Kwon S, Rajagopal L, He W, Meltzer HY. 5-HT 1A parital agonism and 5-HT 7 antagonism restore episodic memory in subchronic phencyclidine-treated mice: role of brain glutamate, dopamine, acetylcholine and GABA. Psychopharmacology (Berl) 2018; 235:2795-2808. [PMID: 30066135 DOI: 10.1007/s00213-018-4972-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 07/11/2018] [Indexed: 12/12/2022]
Abstract
RATIONALE The effect of atypical antipsychotic drugs (AAPDs), e.g., lurasidone, to improve cognitive impairment associated with schizophrenia (CIAS), has been suggested to be due, in part, to enhancing release of dopamine (DA), acetylcholine (ACh), and glutamate (Glu) in cortex and hippocampus. RESULTS The present study found acute lurasidone reversed the cognitive deficit in novel object recognition (NOR) in subchronic (sc) phencyclidine (PCP)-treated mice, an animal model for CIAS. This effect of lurasidone was blocked by pretreatment with the 5-HT1AR antagonist, WAY-100635, or the 5-HT7R agonist, AS 19. Lurasidone significantly increased medial prefrontal cortex (mPFC) ACh, DA, and Glu efflux, all of which were blocked by WAY-100635, with similar effects in the dorsal striatum (dSTR), except for the absence of an effect on Glu increase. AS 19 inhibited Glu, but not DA efflux, in the dSTR. The selective 5-HT7R antagonist, SB-26970, increased mPFC DA, 5-HT, Glu, and, importantly, also GABA efflux and striatal DA, NE, 5-HT, and Glu efflux, indicating tonic inhibition of the release of these neurotransmitters by 5-HT7R stimulation. These results provide new evidence that GABA release in the mPFC is tonically inhibited by 5-HT7R stimulation and suggest that a selective 5-HT7R antagonist might be clinically useful to enhance cortical GABAergic release. All SB-269970 effects were blocked by AS 19 or WAY-100635, suggesting 5-HT1AR agonism is necessary for the release of these neurotransmitters by SB-269970. Lurasidone increased ACh, DA, and NE but not Glu efflux in mPFC and dSTR DA and Glu efflux in 5-HT7 KO mice. CONCLUSION We conclude that lurasidone-induced Glu efflux in mPFC requires 5-HT7R antagonism while its effects on cortical ACh and DA efflux are mainly due to 5-HT1AR stimulation.
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Affiliation(s)
- Mei Huang
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave., Ward Building 7-014, Chicago, IL, 60611, USA
| | - Sunoh Kwon
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave., Ward Building 7-014, Chicago, IL, 60611, USA.,K-herb Research Center, Korea Institute of Oriental Medicine, Daejeon, 34054, Republic of Korea
| | - Lakshmi Rajagopal
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave., Ward Building 7-014, Chicago, IL, 60611, USA
| | - Wenqi He
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave., Ward Building 7-014, Chicago, IL, 60611, USA
| | - Herbert Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave., Ward Building 7-014, Chicago, IL, 60611, USA.
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Lee KKY, Soutar CN, Dringenberg HC. Gating of long-term potentiation (LTP) in the thalamocortical auditory system of rats by serotonergic (5-HT) receptors. Brain Res 2018; 1683:1-11. [PMID: 29325855 DOI: 10.1016/j.brainres.2018.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 11/24/2017] [Accepted: 01/02/2018] [Indexed: 01/01/2023]
Abstract
The neuromodulator serotonin (5-hydroxytryptamine, 5-HT) plays an important role in controlling the induction threshold and maintenance of long-term potentiation (LTP) in the visual cortex and hippocampus of rodents. Serotonergic fibers also innervate the rodent primary auditory cortex (A1), but the regulation of A1 plasticity by 5-HT receptors (5-HTRs) is largely uncharted. Thus, we examined the role of several, predominant 5-HT receptor classes (5-HT1ARs, 5-HT2Rs, and 5-HT3Rs) in gating in vivo LTP induction at A1 synapses of adult, urethane-anesthetized rats. Theta-burst stimulation (TBS) applied to the medial geniculate nucleus resulted in successful LTP induction of field postsynaptic potentials (fPSPs) generated by excitation of thalamocortical and intracortical A1 synapses. Local application (by reverse microdialysis in A1) of the broad-acting 5-HTR antagonist methiothepin suppressed LTP at both thalamocortical and intracortical synapses. In fact, rather than LTP, TBS elicited long-term depression during methiothepin application, an effect that was mimicked by the selective 5-HT2R antagonist ketanserin, but not the 5-HT1AR blocker WAY 100635. Interestingly, antagonism of 5-HT3Rs by granisetron selectively blocked LTP at thalamocortical, but not intracortical A1 synapses. Further, in the absence of TBS, granisetron application resulted in a pronounced increase in fPSP amplitude, suggesting that 5-HT3Rs play an important role in regulating baseline (non-potentiated) transmission at A1 synapses. Together, these results indicate that activation of 5-HT2Rs and 5-HT3Rs, but not 5-HT1ARs, exerts a clear, facilitating effect on LTP induction at A1 synapses, allowing 5-HT to act as a powerful regulator of long-term plasticity induction in the fully matured A1 of mammalian species.
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Affiliation(s)
- Karen K Y Lee
- Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Chloe N Soutar
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Hans C Dringenberg
- Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada; Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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