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Schmalz JT, Kumar G. A computational model of dopaminergic modulation of hippocampal Schaffer collateral-CA1 long-term plasticity. J Comput Neurosci 2021; 50:51-90. [PMID: 34431067 DOI: 10.1007/s10827-021-00793-6] [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: 02/19/2021] [Revised: 05/14/2021] [Accepted: 05/28/2021] [Indexed: 10/20/2022]
Abstract
Dopamine plays a critical role in modulating the long-term synaptic plasticity of the hippocampal Schaffer collateral-CA1 pyramidal neuron synapses (SC-CA1), a widely accepted cellular model of learning and memory. Limited results from hippocampal slice experiments over the last four decades have shown that the timing of the activation of dopamine D1/D5 receptors relative to a high/low-frequency stimulation (HFS/LFS) in SC-CA1 synapses regulates the modulation of HFS/LFS-induced long-term potentiation/depression (LTP/LTD) in these synapses. However, the existing literature lacks a complete picture of how various concentrations of D1/D5 agonists and the relative timing between the activation of D1/D5 receptors and LTP/LTD induction by HFS/LFS, affect the spatiotemporal modulation of SC-CA1 synaptic dynamics. In this paper, we have developed a computational model, a first of its kind, to make quantitative predictions of the temporal dose-dependent modulation of the HFS/LFS induced LTP/LTD in SC-CA1 synapses by various D1/D5 agonists. Our model combines the biochemical effects with the electrical effects at the electrophysiological level. We have estimated the model parameters from the published electrophysiological data, available from diverse hippocampal CA1 slice experiments, in a Bayesian framework. Our modeling results demonstrate the capability of our model in making quantitative predictions of the available experimental results under diverse HFS/LFS protocols. The predictions from our model show a strong nonlinear dependency of the modulated LTP/LTD by D1/D5 agonists on the relative timing between the activated D1/D5 receptors and the HFS/LFS protocol and the applied concentration of D1/D5 agonists.
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Voulalas PJ, Schetz J, Undieh AS. Differential subcellular distribution of rat brain dopamine receptors and subtype-specific redistribution induced by cocaine. Mol Cell Neurosci 2011; 46:645-54. [PMID: 21236347 PMCID: PMC3055788 DOI: 10.1016/j.mcn.2011.01.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 12/07/2010] [Accepted: 01/04/2011] [Indexed: 12/01/2022] Open
Abstract
We investigated the subcellular distribution of dopamine D(1), D(2) and D(5) receptor subtypes in rat frontal cortex, and examined whether psychostimulant-induced elevation of synaptic dopamine could alter the receptor distribution. Differential detergent solubilization and density gradient centrifugation were used to separate various subcellular fractions, followed by semi-quantitative determination of the relative abundance of specific receptor proteins in each fraction. D(1) receptors were predominantly localized to detergent-resistant membranes, and a portion of these receptors also floated on sucrose gradients. These properties are characteristic of proteins found in lipid rafts and caveolae. D(2) receptors exhibited variable distribution between cytoplasmic, detergent-soluble and detergent-resistant membrane fractions, yet were not present in buoyant membranes. Most D(5) receptor immunoreactivity was distributed into the cytoplasmic fraction, failing to sediment at forces up to 300,000g, while the remainder was localized to detergent-soluble membranes in cortex. D(5) receptors were undetectable in detergent-resistant fractions or raft-like subdomains. Following daily cocaine administration for seven days, a significant portion of D(1) receptors translocated from detergent-resistant membranes to detergent-soluble membranes and the cytoplasmic fraction. The distributions of D(5) and D(2) receptor subtypes were not significantly altered by cocaine treatment. These data imply that D(5) receptors are predominantly cytoplasmic, D(2) receptors are diffusely distributed within the cell, whereas D(1) receptors are mostly localized to lipid rafts within the rat frontal cortex. Dopamine receptor subtype localization is susceptible to modulation by pharmacological manipulations that elevate synaptic dopamine, however the functional implications of such drug-induced receptor warrant further investigation.
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Affiliation(s)
- Pamela J Voulalas
- Pharmacokinetics-Biopharmaceutics Laboratory, Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201, USA.
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Undieh AS. Pharmacology of signaling induced by dopamine D(1)-like receptor activation. Pharmacol Ther 2010; 128:37-60. [PMID: 20547182 DOI: 10.1016/j.pharmthera.2010.05.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 05/19/2010] [Indexed: 12/30/2022]
Abstract
Dopamine D(1)-like receptors consisting of D(1) and D(5) subtypes are intimately implicated in dopaminergic regulation of fundamental neurophysiologic processes such as mood, motivation, cognitive function, and motor activity. Upon stimulation, D(1)-like receptors initiate signal transduction cascades that are mediated through adenylyl cyclase or phosphoinositide metabolism, with subsequent enhancement of multiple downstream kinase cascades. The latter actions propagate and further amplify the receptor signals, thus predisposing D(1)-like receptors to multifaceted interactions with various other mediators and receptor systems. The adenylyl cyclase response to dopamine or selective D(1)-like receptor agonists is reliably associated with the D(1) subtype, while emerging evidence indicates that the phosphoinositide responses in native brain tissues may be preferentially mediated through stimulation of the D(5) receptor. Besides classic coupling of each receptor subtype to specific G proteins, additional biophysical models are advanced in attempts to account for differential subcellular distribution, heteromolecular oligomerization, and activity-dependent selectivity of the receptors. It is expected that significant advances in understanding of dopamine neurobiology will emerge from current and anticipated studies directed at uncovering the molecular mechanisms of D(5) coupling to phosphoinositide signaling, the structural features that might enhance pharmacological selectivity for D(5) versus D(1) subtypes, the mechanism by which dopamine may modulate phosphoinositide synthesis, the contributions of the various responsive signal mediators to D(1) or D(5) interactions with D(2)-like receptors, and the spectrum of dopaminergic functions that may be attributed to each receptor subtype and signaling pathway.
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Affiliation(s)
- Ashiwel S Undieh
- Laboratory of Integrative Neuropharmacology, Department of Pharmaceutical Sciences, Thomas Jefferson University School of Pharmacy, 130 South 9th Street, Suite 1510, Philadelphia, PA 19107, USA.
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Phosphatidylinositol-linked novel D(1) dopamine receptor facilitates long-term depression in rat hippocampal CA1 synapses. Neuropharmacology 2009; 57:164-71. [PMID: 19465033 DOI: 10.1016/j.neuropharm.2009.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Revised: 05/02/2009] [Accepted: 05/05/2009] [Indexed: 11/23/2022]
Abstract
Recent work has demonstrated that a phosphatidylinositol (PI)-linked D(1) dopamine receptor selective agonist, SKF83959, mediates phosphatidylinositol hydrolysis via activation of phospholipase C(beta) in brain. Specific contributions of SKF83959 to synaptic plasticity have not been well elucidated. The aim of the current investigation was to characterize the role of SKF83959 on long-term depression (LTD) in the CA1 region of rat hippocampal slices and to explore the molecular events leading to these changes. The results indicated that SKF83959 stimulation significantly depressed field excitatory postsynaptic potentials (fEPSPs) in a dose-dependent manner and facilitated the induction of LTD by LFS. SKF83959-facilitated LTD required activation of phospholipase C (PLC). NMDA receptors were involved in this response. Calcium chelator, BAPTA-AM prevented SKF83959-facilitated LTD, indicating that cytosolic free calcium concentration ([Ca(2+)](i)) elevation could account for this response. Furthermore, SKF83959-facilitated LTD was significantly depressed in the presence of calcineurin (PP2B) inhibitors cyclosporin A (CsA) and associated with a persistent increase in the expression of calcineurin A. Taken together, these findings demonstrate a novel role for PI-linked D(1) dopamine receptor in the neuromodulation of hippocampal LTD.
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Sahu A, Tyeryar KR, Vongtau HO, Sibley DR, Undieh AS. D5 dopamine receptors are required for dopaminergic activation of phospholipase C. Mol Pharmacol 2008; 75:447-53. [PMID: 19047479 DOI: 10.1124/mol.108.053017] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dopamine activates phospholipase C in discrete regions of the mammalian brain, and this action is believed to be mediated through a D(1)-like receptor. Although multiple lines of evidence exclude a role for the D(1) subtype of D(1)-like receptors in the phosphoinositide response, the D(5) subtype has not been similarly examined. Here, mice lacking D(5) dopamine receptors were tested for dopamine agonist-induced phosphoinositide signaling both in vitro and in vivo. The results show that hippocampal, cortical, and striatal tissues of D(5) receptor knockout mice significantly or completely lost the ability to produce inositol phosphate or diacylglycerol messengers after stimulation with dopamine or several selective D(1)-like receptor agonists. Moreover, endogenous inositol-1,4,5-trisphosphate stimulation by the phospholipase C-selective D(1)-like agonist 3-methyl-6-chloro-7,8-dihydroxy-1-[3methylphenyl]-2,3,4,5-tetrahydro-1H-3-benzazepine (SKF83959) was robust in wild-type animals but undetectable in the D(5) receptor mutants. Hence, D(5) receptors are required for dopamine and selective D(1)-like agonists to induce phospholipase C-mediated phosphoinositide signaling in the mammalian brain.
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Affiliation(s)
- Asha Sahu
- Department of Pharmaceutical Sciences, Laboratory of Integrative Neuropharmacology, Thomas Jefferson University School of Pharmacy, Philadelphia, PA 19107, USA
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Liu J, Wang F, Huang C, Long LH, Wu WN, Cai F, Wang JH, Ma LQ, Chen JG. Activation of phosphatidylinositol-linked novel D1 dopamine receptor contributes to the calcium mobilization in cultured rat prefrontal cortical astrocytes. Cell Mol Neurobiol 2008; 29:317-28. [PMID: 18975071 DOI: 10.1007/s10571-008-9323-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2008] [Accepted: 10/09/2008] [Indexed: 12/23/2022]
Abstract
Recent evidences indicate the existence of an atypical D(1) dopamine receptor other than traditional D(1) dopamine receptor in the brain that mediates PI hydrolysis via activation of phospholipase C(beta) (PLC(beta)). To further understand the basic physiological function of this receptor in brain, the effects of a selective phosphoinositide (PI)-linked D(1) dopamine receptor agonist SKF83959 on cytosolic free calcium concentration ([Ca(2+)](i)) in cultured rat prefrontal cortical astrocytes were investigated by calcium imaging. The results indicated that SKF83959 caused a transient dose-dependent increase in [Ca(2+)](i). Application of D(1) receptor, but not D(2), alpha(1) adrenergic, 5-HT receptor, or cholinergic antagonist prevented SKF83959-induced [Ca(2+)](i) rise, indicating that activation of the D(1) dopamine receptor was essential for this response. Increase in [Ca(2+)](i) was a two-step process characterized by an initial increase in [Ca(2+)](i) mediated by release from intracellular stores, supplemented by influx through voltage-gated calcium channels, receptor-operated calcium channels, and capacitative Ca(2+) entry. Furthermore, SKF83959-stimulated increase in [Ca(2+)](i) was abolished following treatment with a PLC inhibitor. Overall, these results suggested that activation of D(1) receptor by SKF83959 mediates a dose-dependent mobilization of [Ca(2+)](i) via the PLC signaling pathway in cultured rat prefrontal cortical astrocytes.
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Affiliation(s)
- Jue Liu
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, #13 Hangkong Road, Wuhan, Hubei, 430030, China
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Dai R, Ali MK, Lezcano N, Bergson C. A crucial role for cAMP and protein kinase A in D1 dopamine receptor regulated intracellular calcium transients. Neurosignals 2008; 16:112-23. [PMID: 18253052 DOI: 10.1159/000111557] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
D1-like dopamine receptors stimulate Ca(2+) transients in neurons but the effector coupling and signaling mechanisms underlying these responses have not been elucidated. Here we investigated potential mechanisms using both HEK 293 cells that stably express D1 receptors (D1HEK293) and hippocampal neurons in culture. In D1HEK293 cells, the full D1 receptor agonist SKF 81297 evoked a robust dose-dependent increase in Ca(2+)(i) following 'priming' of endogenous G(q/11)-coupled muscarinic or purinergic receptors. The effect of SKF81297 could be mimicked by forskolin or 8-Br-cAMP. Further, cholera toxin and the cAMP-dependent protein kinase (PKA) inhibitors, KT5720 and H89, as well as thapsigargin abrogated the D1 receptor evoked Ca(2+) transients. Removal of the priming agonist and treatment with the phospholipase C inhibitor U73122 also blocked the SKF81297-evoked responses. D1R agonist did not stimulate IP(3) production, but pretreatment of cells with the D1R agonist potentiated G(q)-linked receptor agonist mobilization of intracellular Ca(2+) stores. In neurons, SKF81297 and SKF83959, a partial D1 receptor agonist, promoted Ca(2+) oscillations in response to G(q/11)-coupled metabotropic glutamate receptor (mGluR) stimulation. The effects of both D1R agonists on the mGluR-evoked Ca(2+) responses were PKA dependent. Altogether the data suggest that dopamine D1R activation and ensuing cAMP production dynamically regulates the efficiency and timing of IP(3)-mediated intracellular Ca(2+) store mobilization.
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Affiliation(s)
- Rujuan Dai
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912-2300, USA
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Chen L, Bohanick JD, Nishihara M, Seamans JK, Yang CR. Dopamine D1/5 receptor-mediated long-term potentiation of intrinsic excitability in rat prefrontal cortical neurons: Ca2+-dependent intracellular signaling. J Neurophysiol 2007; 97:2448-64. [PMID: 17229830 DOI: 10.1152/jn.00317.2006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Prefrontal cortex (PFC) dopamine D1/5 receptors modulate long- and short-term neuronal plasticity that may contribute to cognitive functions. Synergistic to synaptic strength modulation, direct postsynaptic D1/5 receptor activation also modulates voltage-dependent ionic currents that regulate spike firing, thus altering the neuronal input-output relationships in a process called long-term potentiation of intrinsic excitability (LTP-IE). Here, the intracellular signals that mediate this D1/5 receptor-dependent LTP-IE were determined using whole cell current-clamp recordings in layer V/VI rat pyramidal neurons from PFC slices. After blockade of all major amino acid receptors (V(hold) = -65 mV) brief tetanic stimulation (20 Hz) of local afferents or application of the D1 agonist SKF81297 (0.2-50 microM) induced LTP-IE, as shown by a prolonged (>40 min) increase in depolarizing pulse-evoked spike firing. Pretreatment with the D1/5 antagonist SCH23390 (1 microM) blocked both the tetani- and D1/5 agonist-induced LTP-IE, suggesting a D1/5 receptor-mediated mechanism. The SKF81297-induced LTP-IE was significantly attenuated by Cd(2+), [Ca(2+)](i) chelation, by inhibition of phospholipase C, protein kinase-C, and Ca(2+)/calmodulin kinase-II, but not by inhibition of adenylate cyclase, protein kinase-A, MAP kinase, or L-type Ca(2+) channels. Thus this form of D1/5 receptor-mediated LTP-IE relied on Ca(2+) influx via non-L-type Ca(2+) channels, activation of PLC, intracellular Ca(2+) elevation, activation of Ca(2+)-dependent CaMKII, and PKC to mediate modulation of voltage-dependent ion channel(s). This D1/5 receptor-mediated modulation by PKC coexists with the previously described PKA-dependent modulation of K(+) and Ca(2+) currents to dynamically regulate overall excitability of PFC neurons.
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Affiliation(s)
- Long Chen
- National Standard Lab of Pharmacology for Chinese Materia Medica, Research Center of Acupuncture and Pharmacology, Nanjing University of Traditional Chinese Medicine, Nanjing, China
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Ming Y, Zhang H, Long L, Wang F, Chen J, Zhen X. Modulation of Ca2+ signals by phosphatidylinositol-linked novel D1 dopamine receptor in hippocampal neurons. J Neurochem 2006; 98:1316-23. [PMID: 16771826 DOI: 10.1111/j.1471-4159.2006.03961.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent evidence indicates the existence of a putative novel phosphatidylinositol-linked D1 dopamine receptor in brain that mediates phosphatidylinositol hydrolysis via activation of phospholipase Cbeta. The present work was designed to characterize the Ca(2+) signals regulated by this phosphatidylinositol-linked D(1) dopamine receptor in primary cultures of hippocampal neurons. The results indicated that stimulation of phosphatidylinositol-linked D1 dopamine receptor by its newly identified selective agonist SKF83959 induced a long-lasting increase in basal [Ca(2+)](i) in a time- and dose-dependent manner. Stimulation was observable at 0.1 microm and reached the maximal effect at 30 microm. The [Ca(2+)](i) increase induced by 1 microm SKF83959 reached a plateau in 5 +/- 2.13 min, an average 96 +/- 5.6% increase over control. The sustained elevation of [Ca(2+)](i) was due to both intracellular calcium release and calcium influx. The initial component of Ca(2+) increase through release from intracellular stores was necessary for triggering the late component of Ca(2+) rise through influx. We further demonstrated that activation of phospholipase Cbeta/inositol triphosphate was responsible for SKF83959-induced Ca(2+) release from intracellular stores. Moreover, inhibition of voltage-operated calcium channel or NMDA receptor-gated calcium channel strongly attenuated SKF83959-induced Ca(2+) influx, indicating that both voltage-operated calcium channel and NMDA receptor contribute to phosphatidylinositol-linked D(1) receptor regulation of [Ca(2+)](i).
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Animals, Newborn/physiology
- Calcium/metabolism
- Calcium Channels, L-Type/drug effects
- Calcium Signaling/physiology
- Cells, Cultured
- Dopamine Agonists/pharmacology
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- Hippocampus/cytology
- Hippocampus/physiology
- Isoenzymes/metabolism
- Neurons/physiology
- Phosphatidylinositols/physiology
- Phospholipase C beta
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D1/physiology
- Second Messenger Systems/physiology
- Thapsigargin/pharmacology
- Type C Phospholipases/metabolism
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Affiliation(s)
- Yuling Ming
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, HUST, Wuhan, China
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