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Ma J, Long LH, Hu ZL, Zhang H, Han J, Ni L, Wang F, Chen JG, Wu PF. Activation of D1-like receptor-dependent phosphatidylinositol signal pathway by SKF83959 inhibits voltage-gated sodium channels in cultured striatal neurons. Brain Res 2015; 1615:71-79. [PMID: 25912434 DOI: 10.1016/j.brainres.2015.04.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 04/07/2015] [Accepted: 04/16/2015] [Indexed: 11/15/2022]
Abstract
Dopamine, a key neurotransmitter mediating the rewarding effects, exerts some of its effects by modulating neuronal excitability of striatal medium spiny neurons. A D1-like dopamine receptor-dependent phosphatidylinositol signal pathway exists in the striatum, however little is known about its role in the dopaminergic modulation of striatal neuronal excitability. 3-Methyl-6-chloro-7, 8-hydroxy-1-(3-methylphenyl)-2,3,4,5-tetrahydro-1H-3-benzazepine (SKF83959) is a selective D1 receptor agonist with high-affinity. Here, we observed its effect on the voltage-gated sodium channels (VGSCs) in primary cultured striatal neurons by whole cell patch-clamp technique. We found that SKF83959 induced an inhibition on VGSCs in a dose-dependent manner in striatal neurons (IC50 value: 3.31 ± 0.39 μM), which could be prevented by antagonist of D1 receptor, but not that of D2, α1 adrenergic, or cholinoceptor. The effect of SKF83959 on VGSCs was also prevented by pretreatment with inhibitors of phospholipase C (PLC) and protein kinases C (PKC), but the inositol-1,4,5-phosphate 3 (IP3) antagonist did not occlude SKF83959 (1μM)-induced reduction of VGSCs. These data indicate that SKF83959 inhibits VGSCs in cultured striatal neurons via D1-like receptor-phosphatidylinositol-PKC pathway, which may underlie the dopaminergic modulation on striatal neuronal excitability.
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Affiliation(s)
- Jin Ma
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China
| | - Li-Hong Long
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, Wuhan City, Hubei 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan City, Hubei 430030, China; The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhuang-Li Hu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, Wuhan City, Hubei 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan City, Hubei 430030, China
| | - Hai Zhang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China
| | - Jun Han
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China
| | - Lan Ni
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, Wuhan City, Hubei 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan City, Hubei 430030, China
| | - Fang Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, Wuhan City, Hubei 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan City, Hubei 430030, China; The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jian-Guo Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, Wuhan City, Hubei 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan City, Hubei 430030, China; The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Peng-Fei Wu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei 430030, China; Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, Wuhan City, Hubei 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan City, Hubei 430030, China; The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China.
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Lee SM, Yang Y, Mailman RB. Dopamine D1 receptor signaling: does GαQ-phospholipase C actually play a role? J Pharmacol Exp Ther 2014; 351:9-17. [PMID: 25052835 DOI: 10.1124/jpet.114.214411] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Despite numerous studies showing therapeutic potential, no central dopamine D1 receptor ligand has ever been approved, because of potential limitations, such as hypotension, seizures, and tolerance. Functional selectivity has been widely recognized as providing a potential mechanism to develop novel therapeutics from existing targets, and a highly biased, functionally selective D1 ligand might overcome some of the past limitations. SKF-83959 [6-chloro-3-methyl-1-(m-tolyl)-2,3,4,5-tetrahydro-1H-benzo[d]azepine-7,8-diol] is reported to be a highly biased D1 ligand, having full agonism at D1-mediated activation of phospholipase C (PLC) signaling (via GαQ) and antagonism at D1-mediated adenylate cyclase signaling (via GαOLF/S). For this reason, numerous studies have used this compound to elucidate the physiologic role of D1-PLC signaling, including a novel molecular mechanism (GαQ-PLC activation via D1-D2 heterodimers). There is, however, contradictory literature that suggests that SKF-83959 is actually a partial agonist at both D1-mediated adenylate cyclase and β-arrestin recruitment. Moreover, the D1-mediated PLC stimulation has also been questioned. This Minireview examines 30 years of relevant literature and proposes that the data strongly favor alternate hypotheses: first, that SKF-83959 is a typical D1 partial agonist; and second, that the reported activation of PLC by SKF-83959 and related benzazepines likely is due to off-target effects, not actions at D1 receptors. If these hypotheses are supported by future studies, it would suggest that caution should be used regarding the role of PLC and downstream pathways in D1 signaling.
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Affiliation(s)
- Sang-Min Lee
- Departments of Pharmacology (S.-M.L., Y.Y., R.B.M.) and Neurology (Y.Y., R.B.M.), Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Yang Yang
- Departments of Pharmacology (S.-M.L., Y.Y., R.B.M.) and Neurology (Y.Y., R.B.M.), Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Richard B Mailman
- Departments of Pharmacology (S.-M.L., Y.Y., R.B.M.) and Neurology (Y.Y., R.B.M.), Pennsylvania State University College of Medicine, Hershey, Pennsylvania
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3
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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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4
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Hu XT, Dong Y, Zhang XF, White FJ. Dopamine D2 receptor-activated Ca2+ signaling modulates voltage-sensitive sodium currents in rat nucleus accumbens neurons. J Neurophysiol 2004; 93:1406-17. [PMID: 15590733 DOI: 10.1152/jn.00771.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Receptor-mediated dopamine (DA) modulation of neuronal excitability in the nucleus accumbens (NAc) has been shown to be critically involved in drug addiction and a variety of brain diseases. However, the mechanisms underlying the physiological or pathological molecular process of DA modulation remain largely elusive. Here, we demonstrate that stimulation of DA D2 class receptors (D2R) enhanced voltage-sensitive sodium currents (VSSCs, I(Na)) in freshly dissociated NAc neurons via suppressing tonic activity of the cyclic AMP/PKA cascade and facilitating intracellular Ca2+ signaling. D2R-mediated I(Na) enhancement depended on activation of G(i/o) proteins and was mimicked by direct inhibition of PKA. Furthermore, increasing free [Ca2+]in by activating inositol 1,4,5-triphosphate receptors (IP3Rs), blocking Ca2+ reuptake, or adding buffered Ca2+, all enhanced I(Na). Under these circumstances, D2R-mediated I(Na) enhancement was occluded. In contrast, D2R-mediated I(Na) enhancement was blocked by inhibition of IP3Rs, chelation of free Ca2+, or inhibition of Ca2(+)/calmodulin-activated calcineurin (CaN), but not by inhibition of phospholipase C (PLC). Although stimulation of muscarinic cholinergic receptors (mAChRs) also increased I(Na), this action was blocked by PLC inhibitors. Our findings indicate that D2Rs mediate an enhancement of VSSCs in NAc neurons, in which cytosolic free Ca2+ plays a crucial role. Our results also suggest that D2R-mediated reduction in tonic PKA activity may increase free [Ca2+]in, primarily via disinhibition of IP3Rs. IP3R activation then facilitates Ca2+ signaling and subsequently enhances VSSCs via decreasing PKA-induced phosphorylation and increasing CaN-induced dephosphorylation of Na+ channels. This study provides insight into the complex and dynamic role of D2Rs in the NAc.
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Affiliation(s)
- Xiu-Ti Hu
- Deptartment of Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Rd., North Chicago, IL 60064-3095, USA.
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5
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Mercier D, Falardeau P, Lévesque D. Autoreceptor preference of dopamine D2 receptor agonists correlates with preferential coupling to cyclic AMP. Neuroreport 2001; 12:1473-9. [PMID: 11388433 DOI: 10.1097/00001756-200105250-00036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dopamine autoreceptors control the synaptic release and turnover of dopamine. Some dopamine agonists display a preference for modulation of autoreceptor functions rather than postsynaptic-driven behaviors. However, the nature of this apparent selectivity is still elusive. To investigate this property, we have used an heterologous expression system in which D2S receptors are coupled to both inhibition of cyclic AMP levels and stimulation of inositol triphosphate production. We show that D2-like receptor agonists display distinct potencies on these two second messenger pathways. Moreover, a strong correlation is observed between the potency of agonists to interact with adenylate cyclase and their potency to modulate autoreceptor functions. Such a correlation does not show up with the phospholipase C pathway. This suggests that autoreceptor preference of D2-like receptor agonists may be driven by a preferential interaction with a second messenger system.
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Affiliation(s)
- D Mercier
- Neuroscience Unit, CHUQ Research Center (CHUL), Quebec, Qc, Canada
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6
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D2 dopamine receptors in striatal medium spiny neurons reduce L-type Ca2+ currents and excitability via a novel PLC[beta]1-IP3-calcineurin-signaling cascade. J Neurosci 2001. [PMID: 11124974 DOI: 10.1523/jneurosci.20-24-08987.2000] [Citation(s) in RCA: 347] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In spite of the recognition that striatal D(2) receptors are critical determinants in a variety of psychomotor disorders, the cellular mechanisms by which these receptors shape neuronal activity have remained a mystery. The studies presented here reveal that D(2) receptor stimulation in enkephalin-expressing medium spiny neurons suppresses transmembrane Ca(2+) currents through L-type Ca(2+) channels, resulting in diminished excitability. This modulation is mediated by G(beta)(gamma) activation of phospholipase C, mobilization of intracellular Ca(2+) stores, and activation of the calcium-dependent phosphatase calcineurin. In addition to providing a unifying mechanism to explain the apparently divergent effects of D(2) receptors in striatal medium spiny neurons, this novel signaling linkage provides a foundation for understanding how this pivotal receptor shapes striatal excitability and gene expression.
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7
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Missale C, Nash SR, Robinson SW, Jaber M, Caron MG. Dopamine receptors: from structure to function. Physiol Rev 1998; 78:189-225. [PMID: 9457173 DOI: 10.1152/physrev.1998.78.1.189] [Citation(s) in RCA: 2416] [Impact Index Per Article: 92.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The diverse physiological actions of dopamine are mediated by at least five distinct G protein-coupled receptor subtypes. Two D1-like receptor subtypes (D1 and D5) couple to the G protein Gs and activate adenylyl cyclase. The other receptor subtypes belong to the D2-like subfamily (D2, D3, and D4) and are prototypic of G protein-coupled receptors that inhibit adenylyl cyclase and activate K+ channels. The genes for the D1 and D5 receptors are intronless, but pseudogenes of the D5 exist. The D2 and D3 receptors vary in certain tissues and species as a result of alternative splicing, and the human D4 receptor gene exhibits extensive polymorphic variation. In the central nervous system, dopamine receptors are widely expressed because they are involved in the control of locomotion, cognition, emotion, and affect as well as neuroendocrine secretion. In the periphery, dopamine receptors are present more prominently in kidney, vasculature, and pituitary, where they affect mainly sodium homeostasis, vascular tone, and hormone secretion. Numerous genetic linkage analysis studies have failed so far to reveal unequivocal evidence for the involvement of one of these receptors in the etiology of various central nervous system disorders. However, targeted deletion of several of these dopamine receptor genes in mice should provide valuable information about their physiological functions.
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Affiliation(s)
- C Missale
- Department of Cell Biology, Howard Hughes Medical Institute Laboratories, Duke University Medical Center, Durham, North Carolina, USA
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8
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Izquierdo-Claros RM, Boyano-Adánez MC, Larsson C, Gustavsson L, Arilla E. Acute effects of D1- and D2-receptor agonist and antagonist drugs on somatostatin binding, inhibition of adenylyl cyclase activity and accumulation of inositol 1,4,5-trisphosphate in the rat striatum. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1997; 47:99-107. [PMID: 9221906 DOI: 10.1016/s0169-328x(97)00063-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A recent study carried out by our group demonstrated that exogenous dopamine increases the somatostatin (SS) receptor-effector system in the rat striatum. The present study examined the participation of the D1- and D2-dopaminergic systems in the modulation of the rat striatal SS receptor-effector system by use of the D1-receptor agonist and antagonist SKF 38393 and SCH 23390, respectively, and the D2-receptor agonist and antagonist bromocriptine and raclopride, respectively. In view of the rapid onset of dopamine action, the effect of dopaminergic agents on the SS mechanism of action were studied 3 h after their administration. SKF 38393 (4 mg/kg i.p.) or bromocriptine (2 mg/kg i.p.) administered to male Wistar rats increased the number of 125I-Tyr3-SMS receptors in the striatum (52 and 30%, respectively) without changing the affinity constant. The effect of SKF 38393 on 125I-Tyr3-SMS binding was antagonized by the D1-specific antagonist SCH 23390 (0.25 mg/kg i.p.) whereas the effect of bromocriptine was abolished by the D2-specific antagonist raclopride (5 mg/kg i.p.). No change in binding was produced when SKF 38393 or bromocriptine were added directly to the incubation medium. The acute systemic administration of SCH 23390 or raclopride alone had no effect on the binding of 125I-Tyr3-SMS to its receptors. The increase of the number of 125I-Tyr3-SMS receptor induced by SKF 38393 or bromocriptine was accompanied by an increase in the capacity of SMS 201-995 to inhibit basal and forskolin (FK)-stimulated adenylyl cyclase (AC) activity when compared to the control groups. In addition, the effect of SMS 201-995 on the mass accumulation of inositol 1,4,5-trisphosphate (IP3) was investigated. SKF 38393 as well as bromocriptine increased the capacity of SMS 201-995 to accumulate IP3 in the rat striatum although this effect was only statistically significant in the case of SKF 38393. These results suggest that the activation of D1 and D2 receptors increases the activity of the SS receptor-effector system, the effect being greater in the case of D1 receptors. These findings are consistent with a functional interaction between dopamine and SS in the rat striatum.
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Affiliation(s)
- R M Izquierdo-Claros
- Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
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9
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Yu PY, Eisner GM, Yamaguchi I, Mouradian MM, Felder RA, Jose PA. Dopamine D1A receptor regulation of phospholipase C isoform. J Biol Chem 1996; 271:19503-8. [PMID: 8702641 DOI: 10.1074/jbc.271.32.19503] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In LTK- cells stably transfected with rat D1A receptor cDNA, fenoldopam, a D1 agonist, increased phosphatidylinositol 4, 5-bisphosphate hydrolysis in a time-dependent manner. In the cytosol, phospholipase C (PLC) activity increased (50 +/- 7%) in 30 s, returned to basal level at 4 h, and decreased below basal values by 24 h; in the membrane, PLC activity also increased (36 +/- 13%) in 30 s, returned to basal level at 10 min, and decreased below basal value at 4 and 24 h. Fenoldopam also increased PLC-gamma protein in a time-dependent manner. The latter was blocked by the D1 antagonist SKF83742 and by a D1A antisense oligodeoxynucleotide, indicating involvement of the D1A receptor. The fenoldopam-induced increase in PLC-gamma and activity was mediated by protein kinase A (PKA) since it was blocked by the PKA antagonist Rp-8-CTP-adenosine cyclic 3':5'-monophosphorothioate (Rp-8-CTP-cAMP-S) and mimicked by direct stimulation of adenylyl cyclase with forskolin or by a PKA agonist, Sp-cAMP-S. Protein kinase C (PKC) was also involved, since the fenoldopam-induced increase in PLC-gamma protein was blocked by two different PKC inhibitors, calphostin C and chelerythrine; calphostin C also blocked the fenoldopam-induced increase in PLC activity. In addition, forskolin and a PKA agonist, Sp-8-CTP-cAMP-S, increased PKC activity, and direct stimulation of PKC with phorbol 12-myristate 13-acetate increased PLC-gamma protein and activity, effects that were blocked by calphostin C. We suggest that the D1A-mediated stimulation of PLC occurs as a result of PKA activation. PKA then stimulates PLC-gamma in cytosol and membrane via activation of PKC.
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Affiliation(s)
- P Y Yu
- Department of Pediatrics, Georgetown University Medical Center, Washington, D. C. 20007, USA
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10
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Simpson CS, Morris BJ. Induction of c-fos and zif/268 gene expression in rat striatal neurons, following stimulation of D1-like dopamine receptors, involves protein kinase A and protein kinase C. Neuroscience 1995; 68:97-106. [PMID: 7477939 DOI: 10.1016/0306-4522(95)00122-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Changes in the level of dopaminergic activity in the rat striatum lead to the induction of a number of immediate-early genes, including c-fos and zif/268. These immediate-early genes are thought in turn to alter the rate of transcription of downstream genes. There is evidence that the dopaminergic activation of the c-fos and zif/268 genes in the striatum in vivo is linked to stimulation of D1-like dopamine receptors. We have used primary cultures of embryonic rat striatal neurons to identify the intracellular pathways involved in this response. Dopamine (10 nM-5 microM) caused a marked increase in the levels of c-fos mRNA and zif/268 mRNA in cultured striatal neurons, an effect that was reproduced by the D1-like dopamine receptor agonist SKF38393 (10 nM-5 microM). These actions were attenuated by the D1-like antagonist SCH23390 (1 microM) but not by the D2-like antagonist eticlopride (1 microM). The D2-like agonist quinpirole did not increase zif/268 mRNA above basal levels at concentrations up to 5 microM, but caused a slight increase in the levels of c-fos mRNA. The stimulation of c-fos mRNA levels caused by 1 microM SKF38393 was reduced by 45% following pretreatment with the selective protein kinase A inhibitor KT5720, and by 87% following pretreatment with the selective protein kinase C inhibitor calphostin C. The stimulation of zif/268 mRNA levels caused by 1 microM SKF38393 was reduced by 90% following pretreatment with KT5720, but was not significantly affected by pretreatment with calphostin C. In addition, the actions of SKF38393 to stimulate the expression of both immediate-early genes were attenuated by coadministration of quinpirole. These results suggest that SKF38393 acts on striatal neurons to stimulate c-fos expression predominantly through protein kinase C, but also partially through protein kinase A. Conversely, SKF38393 induces zif/268 expression through protein kinase A. The ability of quinpirole to antagonize the actions of SKF38393 on cultured neurons is consistent with the presence of both D1-like receptors on the same neuronal population.
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Affiliation(s)
- C S Simpson
- Department of Pharmacology, University of Glasgow, U.K
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11
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Kimura K, White BH, Sidhu A. Coupling of human D-1 dopamine receptors to different guanine nucleotide binding proteins. Evidence that D-1 dopamine receptors can couple to both Gs and G(o). J Biol Chem 1995; 270:14672-8. [PMID: 7782330 DOI: 10.1074/jbc.270.24.14672] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Coupling between D-1 dopamine receptors and G proteins in cell lines expressing human D-1 receptors and different G proteins was examined. Pertussis toxin (PTX) treatment of rat pituitary GH4C1 cells significantly reduced, but did not abolish, agonist high affinity binding sites of the D-1 dopamine receptor; in SK-N-MC neuroblastoma cells, PTX failed to have any effect on D-1 high affinity sites. Cholera toxin (CTX) treatment of GH4C1 cells reduced but did not abolish the high affinity sites of D-1 receptors, while in SK-N-MC cells, treatment with CTX abolished all the high affinity sites. Western blot analyses with specific antisera indicated that Gs alpha, Gi1 alpha, Gi3 alpha, and Gq alpha were expressed in both cell lines, while Gi2 alpha and G(o) alpha were expressed in GH4C1 but not SK-N-MC cells. Antisera NEI-805 (anti-Gs alpha) and 9072 (anti-G(o) alpha) immunoprecipitated 24 +/- 4.3 and 34.4 +/- 6.9%, respectively, of G protein-associated D-1 dopamine receptors. Antisera 3646 (anti-Gi1 alpha), 1521 (anti-Gi2 alpha), 1518 (anti-Gi3 alpha), and 0941 (anti-Gq alpha) failed to coimmunoprecipitate appreciable levels of soluble receptors. These data indicate that D-1 dopamine receptors are coupled to both Gs alpha and G(o) alpha but not to Gq alpha.
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Affiliation(s)
- K Kimura
- Department of Pediatrics, Georgetown University Medical Center, Washington, D.C. 20007, USA
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12
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Stoof JC, Drukarch B, de Boer P, Westerink BH. In vitro and in vivo acetylcholine release from rat striatum as a functional paradigm of signal transduction via a D-2 dopamine receptor. Neurochem Int 1995; 20 Suppl:201S-205S. [PMID: 1365426 DOI: 10.1016/0197-0186(92)90239-n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- J C Stoof
- Department of Neurology, Medical Faculty, Free University, Amsterdam, The Netherlands
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13
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Stoof JC, Drukarch B, de Boer P, Westerink BH, Groenewegen HJ. Regulation of the activity of striatal cholinergic neurons by dopamine. Neuroscience 1992; 47:755-70. [PMID: 1579210 DOI: 10.1016/0306-4522(92)90027-y] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- J C Stoof
- Department of Neurology, Medical Faculty, Free University, Amsterdam, The Netherlands
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14
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Fisher SK, Heacock AM, Agranoff BW. Inositol lipids and signal transduction in the nervous system: an update. J Neurochem 1992; 58:18-38. [PMID: 1309233 DOI: 10.1111/j.1471-4159.1992.tb09273.x] [Citation(s) in RCA: 194] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- S K Fisher
- Department of Pharmacology, University of Michigan, Ann Arbor 48104-1687
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15
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Briggs CA, Pollock NJ, Frail DE, Paxson CL, Rakowski RF, Kang CH, Kebabian JW. Activation of the 5-HT1C receptor expressed in Xenopus oocytes by the benzazepines SCH 23390 and SKF 38393. Br J Pharmacol 1991; 104:1038-44. [PMID: 1687364 PMCID: PMC1908831 DOI: 10.1111/j.1476-5381.1991.tb12546.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
1. A cloned 5-HT1C receptor expressed in Xenopus laevis oocytes was used to characterize the action of four dopamine D1-selective benzazepines at the 5-HT1C receptor. Additionally, the apparent binding of the D1-selective benzazepines to 5-HT1C receptors was measured in the choroid plexus of the pig. 2. In voltage-clamped oocytes expressing the cloned 5-HT1C receptor, 5-hydroxytryptamine (5-HT) elicited a characteristic inward current response with an EC50 of 13 nM. SCH 23390 acted as a stereoselective agonist (or partial agonist) with an EC50 of about 550 nM. SKF 38393 (1 microM-1 mM), SKF 77434 (100 microM), and SKF 82958 (100 microM) also acted as agonists (or partial agonists) at the cloned 5-HT1C receptor. SKF 38393 was not stereoselective at the 5-HT1C receptor. 3. The response to SCH 23390 activated slowly and, although the response contained many oscillations characteristic of the activation of the phosphatidylinositol signal transduction system, SCH 23390 rarely elicited the rapid spike-like response seen routinely in response to 5-HT. However, the responses to SKF 38393, SKF 77434, and SKF 82958 were identical in appearance to the response to 5-HT, except that the responses to the benzazepines were smaller. These comparisons were made by applying both a benzazepine and 5-HT to each individual oocyte expressing the cloned 5-HT1C receptor. 4. Consistent with the responses measured in oocytes, SCH 23390 bound stereoselectively to 5-HT1C receptors in the choroid plexus of the pig (Ki = 6.3 nM), and SKF 38393 bound non-stereoselectively with lower affinity (Ki = 2.0-2.2 microM).5. It is concluded that while these benzazepines demonstrate selectivity for the dopamine D1 receptor, they also can act as agonists or partial agonists at the 5-HT1c receptor in situ and as expressed in Xenopus oocytes. The oocyte expression system is useful for studies of the functional pharmacology of these 5-HTic receptors. Information about the pharmacological actions and variations in stereoselectivity among dopamine and 5-HT receptors should be of interest in modelling the interactions of ligands with these G-protein coupled receptors, and in the testing of such models through receptor mutagenesis.
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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
- Benzazepines/pharmacology
- Binding, Competitive/drug effects
- Choroid Plexus/metabolism
- Cloning, Molecular
- Dopamine Agents/pharmacology
- Dopamine Antagonists
- In Vitro Techniques
- Oocytes/drug effects
- Oocytes/metabolism
- RNA, Messenger/metabolism
- Receptors, Dopamine/drug effects
- Receptors, Dopamine D1
- Receptors, Serotonin/drug effects
- Serotonin/pharmacology
- Signal Transduction/drug effects
- Swine
- Xenopus laevis
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Affiliation(s)
- C A Briggs
- Department of Neuroscience, Abbot Laboratories, Abbott Park, Illinois 60064
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Hitzemann R, Dains K, Bier-Langing CM, Zahniser NR. On the selection of mice for haloperidol response and non-response. Psychopharmacology (Berl) 1991; 103:244-50. [PMID: 1827527 DOI: 10.1007/bf02244211] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mice have been selected over eight generations for response and non-response to haloperidol-induced catalepsy. The selection has been asymmetric, with significantly faster divergence for the haloperidol non-responder (HNR) line as compared to the haloperidol responder (HR) line. After six generations of selection, the ED50 in the HNR line was 4.3 mg/kg and 0.4 mg/kg in the HR line. Spiroperidol, fluphenazine and trifluoperazine showed a 10-fold or greater discrimination between lines. Raclopride, a specific dopamine D2 antagonist, showed a 7-fold discrimination between lines. Chlorpromazine, thiothixene, (+) butaclamol and cis-flupenthixol showed a 3-4-fold discrimination between lines. The specific D1 antagonist, SCH 23390, was the most potent cataleptogenic agent tested (ED50 = 0.1 mg/kg) and did not discriminate between the lines. The HR and HNR lines did not differ in post-synaptic D2 receptor affinity or density as assessed by quantitative receptor autoradiography and membrane binding assays. However, A-9 somatodendritic receptor density was 80% higher in the HNR line as compared to the HR line.
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Affiliation(s)
- R Hitzemann
- Department of Psychiatry and Behavioral Sciences, SUNY, Stony Brook 11794-8101
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