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Villalobos-Escobedo FS, Jijón-Lorenzo R, Avalos-Fuentes JA, Paz-Bermúdez F, Recillas-Morales S, Rojas IC, Leyva-Gómez G, Cortés H, Florán B. Dopamine D3 receptor modulates D2 receptor effects on cAMP and GABA release at striatopallidal terminals-Modulation by the Ca 2+-Calmodulin-CaMKII system. Eur J Neurosci 2024; 59:1441-1459. [PMID: 38151481 DOI: 10.1111/ejn.16237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 11/15/2023] [Accepted: 11/21/2023] [Indexed: 12/29/2023]
Abstract
Dopamine D2 receptor (D2R) is expressed in striatopallidal neurons and decreases forskolin-stimulated cyclic adenine monophosphate (cAMP) accumulation and gamma-aminobutyric acid (GABA) release. Dopamine D3 receptor (D3R) mRNA is expressed in a population of striatal D2R-expressing neurons. Also, D3R protein and binding have been reported in the neuropil of globus pallidus. We explore whether D2R and D3R colocalize in striatopallidal terminals and whether D3R modulates the D2R effect on forskolin-stimulated [3H]cAMP accumulation in pallidal synaptosomes and high K+ stimulated-[3H]GABA release in pallidal slices. Previous reports in heterologous systems indicate that calmodulin (CaM) and CaMKII modulate D2R and D3R functions; thus, we study whether this system regulates its functional interaction. D2R immunoprecipitates with CaM, and pretreatment with ophiobolin A or depolarization of synaptosomes with 15 mM of K+ decreases it. Both treatments increase the D2R inhibition of forskolin-stimulated [3H]cAMP accumulation when activated with quinpirole, indicating a negative modulation of CaM on D2R function. Quinpirole also activates D3R, potentiating D2R inhibition of cAMP accumulation in the ophiobolin A-treated synaptosomes. D2R and D3R immunoprecipitate in pallidal synaptosomes and decrease after the kainic acid striatal lesion, indicating the striatal origin of the presynaptic receptors. CaM-kinase II alfa (CaMKIIα) immunoprecipitates with D3R and increases after high K+ depolarization. In the presence of KN62, a CaMKIIα blocker, D3R potentiates D2R effects on cAMP accumulation in depolarized synaptosomes and GABA release in pallidal slices, indicating D3R function regulation by CaMKIIα. Our data indicate that D3R potentiates the D2R effect on cAMP accumulation and GABA release at pallidal terminals, an interaction regulated by the CaM-CaMKIIα system.
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Affiliation(s)
- Flor Selene Villalobos-Escobedo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Rafael Jijón-Lorenzo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - José Arturo Avalos-Fuentes
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Francisco Paz-Bermúdez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Israel Conde Rojas
- Neurobiology of Eating, FES-Iztacala, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
| | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
| | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genómica, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Mexico City, Mexico
| | - Benjamín Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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Sánchez-Zavaleta R, Ávalos-Fuentes JA, González-Hernández AV, Recillas-Morales S, Paz-Bermúdez FJ, Leyva-Gómez G, Cortés H, Florán B. Presynaptic nigral GPR55 receptors stimulate [ 3 H]-GABA release through [ 3 H]-cAMP production and PKA activation and promote motor behavior. Synapse 2022; 76:e22246. [PMID: 35831708 DOI: 10.1002/syn.22246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/16/2022] [Accepted: 07/05/2022] [Indexed: 11/09/2022]
Abstract
Striatal medium-sized spiny neurons express mRNA and protein of GPR55 receptors that stimulate neurotransmitter release; thus, GPR55 could be sent to nigral striatal projections, where it might modulate GABA release and motor behavior. Here we study the presence of GPR55 receptors at striato-nigral terminals, their modulation of GABA release, their signaling pathway, and their effect on motor activity. By double immunohistochemistry, we found the colocation of GPR55 protein and substance P in the dorsal striatum. In slices of the rat substantia nigra, the GPR55 agonists LPI and O-1602 stimulated [3 H]-GABA release induced by high K+ depolarization in a dose-dependent manner. The antagonists CID16020046 and cannabidiol prevented agonist stimulation in a dose-dependent way. The effect of GPR55 on nigral [3 H]-GABA release was prevented by lesion of the striatum with kainic acid, which was accompanied by a decrement of GPR55 protein in nigral synaptosomes, indicating the presynaptic location of receptors. The depletion of internal Ca2+ stores with thapsigargin did not prevent the effect of LPI on [3 H]-GABA release, but the remotion or chelation of external calcium did. Blockade of Gi, Gs, PLC, PKC, or dopamine D1 receptor signaling proteins did not prevent the effect of GPR55 on release. However, the activation of GPR55 stimulated [3 H]-cAMP accumulation and PKA activity. Intranigral unilateral injection of LPI induces contralateral turning. This turning was prevented by CID16020046, cannabidiol, and bicuculline but not by SCH 23390. Our data indicate that presynaptic GPR55 receptors stimulate [3 H]-GABA release at striato-nigral terminals through [3 H]-cAMP production and stimulate motor behavior. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Rodolfo Sánchez-Zavaleta
- Departamento de Fisiología, Biofísica y Neurociencias. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México
| | - José Arturo Ávalos-Fuentes
- Departamento de Fisiología, Biofísica y Neurociencias. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México
| | - Antonio Valentín González-Hernández
- Departamento de Fisiología, Biofísica y Neurociencias. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México
| | | | - Francisco Javier Paz-Bermúdez
- Departamento de Fisiología, Biofísica y Neurociencias. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México
| | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Mexico
| | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Ciudad de México, México
| | - Benjamín Florán
- Departamento de Fisiología, Biofísica y Neurociencias. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México
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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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Cdk5 phosphorylates Ca V1.3 channels and regulates GABA A-mediated miniature inhibitory post-synaptic currents in striato-nigral terminals. Biochem Biophys Res Commun 2020; 524:255-261. [PMID: 31983427 DOI: 10.1016/j.bbrc.2020.01.084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/15/2020] [Indexed: 12/24/2022]
Abstract
Neurotransmission is one of the most important processes in neuronal communication and depends largely on Ca2+ entering synaptic terminals through voltage-gated Ca2+ (CaV) channels. Although the contribution of L-type CaV channels in neurotransmission has not been unambiguously established, increasing evidence suggests a role for these proteins in noradrenaline, dopamine, and GABA release. Here we report the regulation of L-type channels by Cdk5, and its possible effect on GABA release in the substantia nigra pars reticulata (SNpr). Using patch-clamp electrophysiology, we show that Cdk5 inhibition by Olomoucine significantly increases current density through CaV1.3 (L-type) channels heterologously expressed in HEK293 cells. Likewise, in vitro phosphorylation showed that Cdk5 phosphorylates residue S1947 in the C-terminal region of the pore-forming subunit of CaV1.3 channels. Consistent with this, the mutation of serine into alanine (S1947A) prevented the regulation of Cdk5 on CaV1.3 channel activity. Our data also revealed that the inhibition of Cdk5 increased the frequency of high K+-evoked miniature inhibitory postsynaptic currents in rat SNpr neurons, acting on L-type channels. These results unveil a novel regulatory mechanism of GABA release in the SNpr that involves a direct action of Cdk5 on L-type channels.
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Effects of local activation and blockade of dopamine D4 receptors in the spiking activity of the reticular thalamic nucleus in normal and in ipsilateral dopamine-depleted rats. Brain Res 2019; 1712:34-46. [DOI: 10.1016/j.brainres.2019.01.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/08/2019] [Accepted: 01/30/2019] [Indexed: 01/01/2023]
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Addy NA, Nunes EJ, Hughley SM, Small KM, Baracz SJ, Haight JL, Rajadhyaksha AM. The L-type calcium channel blocker, isradipine, attenuates cue-induced cocaine-seeking by enhancing dopaminergic activity in the ventral tegmental area to nucleus accumbens pathway. Neuropsychopharmacology 2018; 43:2361-2372. [PMID: 29773910 PMCID: PMC6180103 DOI: 10.1038/s41386-018-0080-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/18/2018] [Accepted: 04/20/2018] [Indexed: 12/27/2022]
Abstract
Previous preclinical and clinical investigations have focused on the L-type calcium channel (LTCC) as a potential therapeutic target for substance abuse. While some clinical studies have examined the ability of LTCC blockers to alter cocaine's subjective effects, very few LTCC studies have examined cocaine relapse. Here, we examined whether ventral tegmental area (VTA)-specific or systemic administration of the LTCC inhibitor, isradipine, altered cocaine-seeking behavior in a rat model. Male Sprague-Dawley rats first received 10 days of cocaine self-administration training (2 h sessions), where active lever depression resulted in delivery of a ∼0.5 mg/kg cocaine infusion paired with a tone + light cue. Rats then underwent 10 days of forced abstinence, without access to cocaine or cocaine cues. Rats were then returned to the opertant chamber for the cue-induced cocaine-seeking test, where active lever depression in the original training context resulted in tone + light cue presentation. We found VTA specific or systemic isradipine administration robustly attenuated cocaine-seeking, without altering cocaine-taking nor natural reward seeking. Dopamine (DA) signaling in the nucleus accumbens (NAc) core is necessary and sufficient for cue-induced drug-seeking. Surprisingly in our study, isradipine enhanced tonic and phasic DA signaling in cocaine abstinent rats, with no change in sucrose abstinent nor naïve rats. Strikingly, isradipine's behavioral effects were dependent upon NAc core DA receptor activation. Together, our findings reveal a novel mechanism by which the FDA-approved drug, isradipine, could act to decrease cocaine relapse.
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Affiliation(s)
- Nii A. Addy
- 0000000419368710grid.47100.32Department of Psychiatry, Yale School of Medicine, New Haven, CT 06511 USA ,0000000419368710grid.47100.32Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06511 USA ,0000000419368710grid.47100.32Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511 USA
| | - Eric J. Nunes
- 0000000419368710grid.47100.32Department of Psychiatry, Yale School of Medicine, New Haven, CT 06511 USA
| | - Shannon M. Hughley
- 0000000419368710grid.47100.32Department of Psychiatry, Yale School of Medicine, New Haven, CT 06511 USA
| | - Keri M. Small
- 0000000419368710grid.47100.32Department of Psychiatry, Yale School of Medicine, New Haven, CT 06511 USA
| | - Sarah J. Baracz
- 0000000419368710grid.47100.32Department of Psychiatry, Yale School of Medicine, New Haven, CT 06511 USA
| | - Joshua L. Haight
- 0000000419368710grid.47100.32Department of Psychiatry, Yale School of Medicine, New Haven, CT 06511 USA
| | - Anjali M. Rajadhyaksha
- 000000041936877Xgrid.5386.8Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medical College of Cornell University, New York, NY 10065 USA ,000000041936877Xgrid.5386.8Feil Family Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY 10065 USA
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Calcium currents in striatal fast-spiking interneurons: dopaminergic modulation of Ca V1 channels. BMC Neurosci 2018; 19:42. [PMID: 30012109 PMCID: PMC6048700 DOI: 10.1186/s12868-018-0441-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/07/2018] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Striatal fast-spiking interneurons (FSI) are a subset of GABAergic cells that express calcium-binding protein parvalbumin (PV). They provide feed-forward inhibition to striatal projection neurons (SPNs), receive cortical, thalamic and dopaminergic inputs and are coupled together by electrical and chemical synapses, being important components of the striatal circuitry. It is known that dopamine (DA) depolarizes FSI via D1-class DA receptors, but no studies about the ionic mechanism of this action have been reported. Here we ask about the ion channels that are the effectors of DA actions. This work studies their Ca2+ currents. RESULTS Whole-cell recordings in acutely dissociated and identified FSI from PV-Cre transgenic mice were used to show that FSI express an array of voltage gated Ca2+ channel classes: CaV1, CaV2.1, CaV2.2, CaV2.3 and CaV3. However, CaV1 Ca2+ channel carries most of the whole-cell Ca2+ current in FSI. Activation of D1-like class of DA receptors by the D1-receptor selective agonist SKF-81297 (SKF) enhances whole-cell Ca2+ currents through CaV1 channels modulation. A previous block of CaV1 channels with nicardipine occludes the action of the DA-agonist, suggesting that no other Ca2+ channel is modulated by D1-receptor activation. Bath application of SKF in brain slices increases the firing rate and activity of FSI as measured with both whole-cell and Ca2+ imaging recordings. These actions are reduced by nicardipine. CONCLUSIONS The present work discloses one final effector of DA modulation in FSI. We conclude that the facilitatory action of DA in FSI is in part due to CaV1 Ca2+ channels positive modulation.
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Jijón-Lorenzo R, Caballero-Florán IH, Recillas-Morales S, Cortés H, Avalos-Fuentes JA, Paz-Bermúdez FJ, Erlij D, Florán B. Presynaptic Dopamine D2 Receptors Modulate [ 3H]GABA Release at StriatoPallidal Terminals via Activation of PLC → IP3 → Calcineurin and Inhibition of AC → cAMP → PKA Signaling Cascades. Neuroscience 2017; 372:74-86. [PMID: 29292080 DOI: 10.1016/j.neuroscience.2017.12.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/14/2017] [Accepted: 12/23/2017] [Indexed: 01/11/2023]
Abstract
Striatal dopamine D2 receptors activate the PLC → IP3 → Calcineurin-signaling pathway to modulate the neural excitability of En+ Medium-sized Spiny GABAergic neurons (MSN) through the regulation of L-type Ca2+ channels. Presynaptic dopaminergic D2 receptors modulate GABA release at striatopallidal terminals through L-type Ca2+ channels as well, but their signaling pathway is still undetermined. Since D2 receptors are Gi/o-coupled and negatively modulate adenylyl cyclase (AC), we investigated whether presynaptic D2 receptors modulate GABA release through the same signaling cascade that controls excitability in the striatum or by the inhibition of AC and decreased PKA activity. Activation of D2 receptors stimulated formation of [3H]IP1 and decreased Forskolin-stimulated [3H]cAMP accumulation in synaptosomes from rat Globus Pallidus. D2 receptor activation with Quinpirole in the presence of L 745,870 decreased, in a dose-dependent manner, K+-induced [3H]GABA release in pallidal slices. The effect was prevented by the pharmacological blockade of Gi/o βγ subunit effects with Gallein, PLC with U 73122, IP3 receptor activation with 4-APB, Calcineurin with FK506. In addition, when release was stimulated with Forskolin to activate AC, D2 receptors also decreased K+-induced [3H]GABA release, an effect occluded with the effect of the blockade of PKA with H89 or stimulation of release with the cAMP analog 8-Br-cAMP. These data indicate that D2 receptors modulate [3H]GABA release at striatopallidal terminals by activating the PLC → IP3 → Calcineurin-signaling cascade, the same one that modulates excitability in soma. Additionally, D2 receptors inhibit release when AC is active. Both mechanisms appear to converge to regulate the activity of presynaptic L-type Ca2+ channels.
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Affiliation(s)
- Rafael Jijón-Lorenzo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Isaac Hiram Caballero-Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | | | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Ciudad de México, Mexico
| | - José Arturo Avalos-Fuentes
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Francisco Javier Paz-Bermúdez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - David Erlij
- Department of Physiology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Benjamín Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico.
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Caballero-Florán RN, Conde-Rojas I, Oviedo Chávez A, Cortes-Calleja H, Lopez-Santiago LF, Isom LL, Aceves J, Erlij D, Florán B. Cannabinoid-induced depression of synaptic transmission is switched to stimulation when dopaminergic tone is increased in the globus pallidus of the rodent. Neuropharmacology 2016; 110:407-418. [PMID: 27506997 DOI: 10.1016/j.neuropharm.2016.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 08/02/2016] [Accepted: 08/05/2016] [Indexed: 11/27/2022]
Abstract
Because activation of D2 receptors reverses the neurochemical effects of cannabinoids, we examined whether increasing dopaminergic tone in the globus pallidus (GPe) switches cannabinoid induced depression of synaptic transmission. GABAergic synaptic currents evoked in pallidal neurons by stimulation of striatal projections (IPSCs) were depressed by perfusion with the CB1R agonist ACEA. Coactivation of D2Rs with quinpirole converted the depression into stimulation. Pretreatment with pertussis toxin (PTX) to limit Gi/o protein coupling also switched the CB1R-induced depression of IPSCs. The stimulation of IPSCs was blocked by the selective PKA blocker H89. Changes in the paired pulse ratio during both inhibitory and stimulatory responses indicate that the effects are due to changes in transmitter release. Postsynaptic depolarization induces endocannabinoid release that inhibits transmitter release (DSI). When D2Rs were activated with quinpirole, depolarization increased transmission instead of depressing it. This increase was blocked by AM251. We also examined the effects of CB1R/D2R coactivation on cAMP accumulation in the GPe to further verify that the AC/PKA cascade is involved. CB1R/D2R coactivation converted the inhibition of cAMP seen when each receptor is stimulated alone into a stimulation. We also determined the effects on turning behavior of unilateral injection of ACEA into the GPe of awake animals and its modification by dopamine antagonists. Blockade of D2 family receptors with sulpiride antagonized the motor effects of ACEA. We show, for the first time, that cannabinoid-inhibition of synaptic transmission in the GPe becomes a stimulation after D2Rs or PTX treatment and that the switch is probably relevant for the control of motor behavior.
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Affiliation(s)
- Rene Nahum Caballero-Florán
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Israel Conde-Rojas
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | | | - Hernán Cortes-Calleja
- Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute, Mexico City, Mexico
| | - Luis F Lopez-Santiago
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jorge Aceves
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - David Erlij
- Department of Physiology SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Benjamín Florán
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico.
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Region-specific effects of repeated ketamine administration on the presynaptic GABAergic neurochemistry in rat brain. Neurochem Int 2015; 91:13-25. [PMID: 26492822 DOI: 10.1016/j.neuint.2015.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 09/29/2015] [Accepted: 10/15/2015] [Indexed: 12/12/2022]
Abstract
A growing body of evidence indicates that clinical use of ketamine as a promising antidepressant can be accompanied by psychotic-like side effects. Although, the generation of such effects is thought to be attributed to dysfunction of prefrontal GABAergic interneurons, the mechanism underlying ketamine's propsychotic-like action is not fully understood. Due to wide spectrum of behavioral abnormalities, it is hypothesized that ketamine action is not limited to only cortical GABA metabolism but may also involve alterations in other functional brain areas. To test it, we treated rats with ketamine (30 mg/kg, i.p.) for 5 days, and next we analyzed GABA metabolizing enzymes in cortex, cerebellum, hippocampus and striatum. Our results demonstrated that diminished GAD67 expression in cortex, cerebellum (by ∼60%) and in hippocampus (by ∼40%) correlated with lowered protein level in these areas. The expression of GAD65 isoform decreased by ∼45% in striatum, but pronounced increase by ∼90% was observed in hippocampus. Consecutively, reduction in glutamate decarboxylase activity and GABA concentration were detected in cortex, cerebellum and striatum, but not in hippocampus. Ketamine administration decreased GABA transaminase protein in cortex and striatum (by ∼50% and 30%, respectively), which was reflected in diminished activity of the enzyme. Also, a significant drop in succinic semialdehyde dehydrogenase activity in cortex, cerebellum and striatum was present. These data suggest a reduced utilization of GABA for energetic purposes. In addition, we observed synaptic GABA release to be reduced by ∼30% from striatal terminals. It correlated with lowered KCl-induced Ca(2+) influx and decreased amount of L-type voltage-dependent calcium channel. Our results indicate that unique changes in GABA metabolism triggered by chronic ketamine treatment in functionally distinct brain regions may be involved in propsychotic-like effects of this drug.
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