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Dwyer GE, Johnsen E, Hugdahl K. NMDAR dysfunction and the regulation of dopaminergic transmission in schizophrenia. Schizophr Res 2024; 271:19-27. [PMID: 39002526 DOI: 10.1016/j.schres.2024.07.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/27/2024] [Accepted: 07/07/2024] [Indexed: 07/15/2024]
Abstract
A substantial body of evidence implicates dysfunction in N-methyl-d-aspartate receptors (NMDARs) in the pathophysiology of schizophrenia. This article illustrates how NMDAR dysfunction may give rise to many of the neurobiological phenomena frequently associated with schizophrenia with a particular focus on how NMDAR dysfunction affects the thalamic reticular nucleus (nRT) and pedunculopontine tegmental nucleus (PPTg). Furthermore, this article presents a model for schizophrenia illustrating how dysfunction in the nRT may interrupt prefrontal regulation of midbrain dopaminergic neurons, and how dysfunction in the PPTg may drive increased, irregular burst firing.
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Affiliation(s)
- Gerard Eric Dwyer
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway; NORMENT Centre of Excellence, Haukeland University Hospital, Bergen, Norway.
| | - Erik Johnsen
- NORMENT Centre of Excellence, Haukeland University Hospital, Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Kenneth Hugdahl
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Bergen, Norway; Department of Radiology, Haukeland University Hospital, Bergen, Norway
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Aguirre-Rodríguez CA, Delgado A, Alatorre A, Oviedo-Chávez A, Martínez-Escudero JR, Barrientos R, Querejeta E. Local activation of CB1 receptors by synthetic and endogenous cannabinoids dampens burst firing mode of reticular thalamic nucleus neurons in rats under ketamine anesthesia. Exp Brain Res 2024:10.1007/s00221-024-06889-6. [PMID: 38980339 DOI: 10.1007/s00221-024-06889-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024]
Abstract
The reticular thalamic nucleus (RTN) is a thin shell that covers the dorsal thalamus and controls the overall information flow from the thalamus to the cerebral cortex through GABAergic projections that contact thalamo-cortical neurons (TC). RTN neurons receive glutamatergic afferents fibers from neurons of the sixth layer of the cerebral cortex and from TC collaterals. The firing mode of RTN neurons facilitates the generation of sleep-wake cycles; a tonic mode or desynchronized mode occurs during wake and REM sleep and a burst-firing mode or synchronized mode is associated with deep sleep. Despite the presence of cannabinoid receptors CB1 (CB1Rs) and mRNA that encodes these receptors in RTN neurons, there are few works that have analyzed the participation of endocannabinoid-mediated transmission on the electrical activity of RTN. Here, we locally blocked or activated CB1Rs in ketamine anesthetized rats to analyze the spontaneous extracellular spiking activity of RTN neurons. Our results show the presence of a tonic endocannabinoid input, since local infusion of AM 251, an antagonist/inverse agonist, modifies RTN neurons electrical activity; furthermore, local activation of CB1Rs by anandamide or WIN 55212-2 produces heterogeneous effects in the basal spontaneous spiking activity, where the main effect is an increase in the spiking rate accompanied by a decrease in bursting activity in a dose-dependent manner; this effect is inhibited by AM 251. In addition, previous activation of GABA-A receptors suppresses the effects of CB1Rs on reticular neurons. Our results show that local activation of CB1Rs primarily diminishes the burst firing mode of RTn neurons.
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Affiliation(s)
- Carlos A Aguirre-Rodríguez
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
| | - Alfonso Delgado
- Departamento de Fisiología Experimental, Facultad de Medicina y Ciencias Biomédicas, Universidad Autónoma de Chihuahua, Circuito Universitario Campus II, 31127, Chihuahua, Chihuahua, México
| | - Alberto Alatorre
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
| | - Aldo Oviedo-Chávez
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
| | - José R Martínez-Escudero
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
| | - Rafael Barrientos
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México
| | - Enrique Querejeta
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México.
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México, 11340, México.
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Barrientos R, Alatorre A, Oviedo-Chávez A, Delgado A, Nielsen N, Querejeta E. Tonic serotonergic input increases the burst firing mode and diminishes the firing rate of reticular thalamic nucleus neurons through 5-HT1A receptors activation in anesthetized rats. Exp Brain Res 2022; 240:1341-1356. [PMID: 35234992 DOI: 10.1007/s00221-022-06328-4] [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: 01/04/2022] [Accepted: 02/07/2022] [Indexed: 11/30/2022]
Abstract
The reticular thalamic nucleus (RTn) is a thin shell of GABAergic neurons that covers the dorsal thalamus that regulate the global activity of all thalamic nuclei. RTn controls the flow of information between thalamus and cerebral cortex since it receives glutamatergic information from collaterals of thalamo-cortical (TCs) and cortico-thalamic neurons. It also receives aminergic information from several brain stem nuclei, including serotonergic fibers originated in the dorsal raphe nucleus. RTn neurons express serotonergic receptors including the 5-HT1A subtype, however, the role of this receptor in the RTn electrical activity has been scarcely analyzed. In this work, we recorded in vivo the unitary spontaneous electrical activity of RTn neurons in anesthetized rats; our study aimed to obtain information about the effects of 5-HT1A receptors in RTn neurons. Local application of fluoxetine (a serotonin reuptake inhibitor) increases burst firing index accompanied by a decrease in the basal spiking rate. Local application of different doses of serotonin and 8-OH-DPAT (a specific 5-HT1A receptor agonist) causes a similar response to fluoxetine effects. Local 5-HT1A receptors blockade produces opposite effects and suppresses the effect by 8-OH-DPAT. Our findings indicate the presence of a serotonergic tonic discharge in the RTn that increases the burst firing index and simultaneously decreases the basal spiking frequency through 5-HT1A receptors activation.
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Affiliation(s)
- Rafael Barrientos
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Alberto Alatorre
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Aldo Oviedo-Chávez
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Alfonso Delgado
- Departamento de Fisiología Experimental, Facultad de Medicina y Ciencias Biomédicas, Universidad Autónoma de Chihuahua, Circuito Universitario Campus II, 31127, Chihuahua, Mexico
| | - Nielsine Nielsen
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico
| | - Enrique Querejeta
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico, Nacional. Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico.
- Sección de Investigación y Posgrado de la Escuela Superior de Medicina del IPN, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340, Colonia Casco de Santo Tomás, CdMx, Mexico.
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Conde Rojas I, Acosta-García J, Caballero-Florán RN, Jijón-Lorenzo R, Recillas-Morales S, Avalos-Fuentes JA, Paz-Bermúdez F, Leyva-Gómez G, Cortés H, Florán B. Dopamine D4 receptor modulates inhibitory transmission in pallido-pallidal terminals and regulates motor behavior. Eur J Neurosci 2020; 52:4563-4585. [PMID: 33098606 DOI: 10.1111/ejn.15020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 12/28/2022]
Abstract
Two major groups of terminals release GABA within the Globus pallidus; one group is constituted by projections from striatal neurons, while endings of the intranuclear collaterals form the other one. Each neurons' population expresses different subtypes of dopamine D2-like receptors: D2 R subtype is expressed by encephalin-positive MSNs, while pallidal neurons express the D4 R subtype. The D2 R modulates the firing rate of striatal neurons and GABA release at their projection areas, while the D4 R regulates Globus pallidus neurons excitability and GABA release at their projection areas. However, it is unknown if these receptors control GABA release at pallido-pallidal collaterals and regulate motor behavior. Here, we present neurochemical evidence of protein content and binding of D4 R in pallidal synaptosomes, control of [3 H] GABA release in pallidal slices of rat, electrophysiological evidence of the presence of D4 R on pallidal recurrent collaterals in mouse slices, and turning behavior induced by D4 R antagonist microinjected in amphetamine challenged rats. As in projection areas of pallidal neurons, GABAergic transmission in pallido-pallidal recurrent synapses is under modulation of D4 R, while the D2 R subtype, as known, modulates striato-pallidal projections. Also, as in projection areas, D4 R contributes to control the motor activity differently than D2 R. This study could help to understand the organization of intra-pallidal circuitry.
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Affiliation(s)
- Israel Conde Rojas
- Departamento de Fisiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México, México
| | | | | | - Rafael Jijón-Lorenzo
- Departamento de Fisiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México, México
| | - Sergio Recillas-Morales
- Faculty of Veterinary Medicine, Universidad Autónoma del Estado de México, Toluca, Estado de México, México
| | - José Arturo Avalos-Fuentes
- Departamento de Fisiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México, México
| | - Francisco Paz-Bermúdez
- Departamento de Fisiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México, México
| | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genómica, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Ciudad de México, México
| | - Benjamín Florán
- Departamento de Fisiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México, México
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A single psychotomimetic dose of ketamine decreases thalamocortical spindles and delta oscillations in the sedated rat. Schizophr Res 2020; 222:362-374. [PMID: 32507548 DOI: 10.1016/j.schres.2020.04.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/18/2020] [Accepted: 04/19/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND In patients with psychotic disorders, sleep spindles are reduced, supporting the hypothesis that the thalamus and glutamate receptors play a crucial etio-pathophysiological role, whose underlying mechanisms remain unknown. We hypothesized that a reduced function of NMDA receptors is involved in the spindle deficit observed in schizophrenia. METHODS An electrophysiological multisite cell-to-network exploration was used to investigate, in pentobarbital-sedated rats, the effects of a single psychotomimetic dose of the NMDA glutamate receptor antagonist ketamine in the sensorimotor and associative/cognitive thalamocortical (TC) systems. RESULTS Under the control condition, spontaneously-occurring spindles (intra-frequency: 10-16 waves/s) and delta-frequency (1-4 Hz) oscillations were recorded in the frontoparietal cortical EEG, in thalamic extracellular recordings, in dual juxtacellularly recorded GABAergic thalamic reticular nucleus (TRN) and glutamatergic TC neurons, and in intracellularly recorded TC neurons. The TRN cells rhythmically exhibited robust high-frequency bursts of action potentials (7 to 15 APs at 200-700 Hz). A single administration of low-dose ketamine fleetingly reduced TC spindles and delta oscillations, amplified ongoing gamma-(30-80 Hz) and higher-frequency oscillations, and switched the firing pattern of both TC and TRN neurons from a burst mode to a single AP mode. Furthermore, ketamine strengthened the gamma-frequency band TRN-TC connectivity. The antipsychotic clozapine consistently prevented the ketamine effects on spindles, delta- and gamma-/higher-frequency TC oscillations. CONCLUSION The present findings support the hypothesis that NMDA receptor hypofunction is involved in the reduction in sleep spindles and delta oscillations. The ketamine-induced swift conversion of ongoing TC-TRN activities may have involved at least both the ascending reticular activating system and the corticothalamic pathway.
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G A, O P, E CM, M GR. Reduction of dopaminergic transmission in the globus pallidus increases anxiety-like behavior without altering motor activity. Behav Brain Res 2020; 386:112589. [PMID: 32194191 DOI: 10.1016/j.bbr.2020.112589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/29/2022]
Abstract
The globus pallidus (GP) plays an important role in the flow of information between input and output structures of the basal ganglia (BG) circuit. In addition to participating in motor control, the GP may also be involved in cognitive and emotional functions related to the symptoms of patients with Parkinson's disease (PD). Since the GP receives dopaminergic innervation from the substantia nigra pars compacta (SNc), it is important to determine whether a local dopamine (DA) deficit in the GP is related not only to motor but also to the cognitive and emotional alterations of PD. The aim of this study was to examine the effects of lesions in the GP (induced by 6-OHDA) on anxiety, depression and ambulation in rats. Such lesions are known to reduce dopaminergic innervation in this brain structure. Additionally, the effect on DA receptors in the GP was tested by local administration of the dopamine agonist PD168,077, antagonist haloperidol and psychostimulant amphetamine. Experimental anxiety was evaluated with the elevated plus maze (EPM), burying behavior test (BBT) and social interaction test, while depressive-like behavior was assessed with the sucrose preference test. Rats with unilateral and bilateral lesions showed a higher level of anxiety than intact animals in both the EPM and BBT, an effect also obtained after intrapallidal injection of haloperidol. The administration of methamphetamine or PD-168.077 caused the opposite effect. The dopaminergic lesions in the GP did not affect sucrose preference, social interaction or ambulation. These results show that dopamine in the GP, acting through D2 or D4 receptors, may be involved in the manifestation of anxiety, a non-motor symptom of PD that often appears before motor symptoms.
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Affiliation(s)
- Avila G
- Escuela Nacional de Ciencias Biológicas, Instituto Politecnico Nacional, Wilfrido Massieu sn, San Pedro Zacatenco, CP 07738, Ciudad de México, Mexico
| | - Picazo O
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Diaz Mirón, Col. Santo Tomás CP.11340, Ciudad de México, Mexico
| | - Chuc-Meza E
- Escuela Nacional de Ciencias Biológicas, Instituto Politecnico Nacional, Wilfrido Massieu sn, San Pedro Zacatenco, CP 07738, Ciudad de México, Mexico
| | - García-Ramirez M
- Escuela Nacional de Ciencias Biológicas, Instituto Politecnico Nacional, Wilfrido Massieu sn, San Pedro Zacatenco, CP 07738, Ciudad de México, Mexico.
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