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Cruces-Solis H, Nissen W, Ferger B, Arban R. Whole-brain signatures of functional connectivity after bidirectional modulation of the dopaminergic system in mice. Neuropharmacology 2020; 178:108246. [PMID: 32771528 DOI: 10.1016/j.neuropharm.2020.108246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/09/2020] [Accepted: 07/14/2020] [Indexed: 10/23/2022]
Abstract
While neuropsychiatric drugs influence neural activity across multiple brain regions, the current understanding of their mechanism of action derives from studies that investigate an influence of a given drug onto a pre-selected and small number of brain regions. To understand how neuropsychiatric drugs affect coordinated activity across brain regions and to detect the brain regions most relevant to pharmacological action in an unbiased way, studies that assess brain-wide neuronal activity are paramount. Here, we used whole-brain immunostaining of the neuronal activity marker cFOS, and graph theory to generate brain-wide maps of neuronal activity upon pharmacological challenges. We generated brain-wide maps 2.5 h after treatment of the atypical dopamine transporter inhibitor modafinil (10, 30, and 100 mg/kg) or the vesicular monoamine transporter 2 inhibitor tetrabenazine (0.25, 0.5 and 1 mg/kg). Modafinil increased the number of cFOS positive neurons in a dose-dependent manner. Moreover, modafinil significantly reduced functional connectivity across the entire brain. Graph theory analysis revealed that modafinil decreased the node degree of cortical and subcortical regions at the three doses tested, followed by a reduction in global efficiency. Simultaneously, we identified highly interconnected hub regions that emerge exclusively upon modafinil treatment. These regions were the mediodorsal thalamus, periaqueductal gray, subiculum, and rhomboid nucleus. On the other hand, while tetrabenazine had mild effects on cFOS counts, it reduced functional connectivity across the entire brain, cortical node degree, and global efficiency. As hub regions, we identified the substantia innominata and ventral pallidum. Our results uncovered novel mechanisms of action at a brain-wide scale for modafinil and tetrabenazine. Our analytical approach offers a tool to characterize signatures of whole-brain functional connectivity for drug candidates and to identify potential undesired effects at a mesoscopic scale. Additionally, it offers a guide towards targeted experiments on newly identified hub regions.
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Affiliation(s)
- Hugo Cruces-Solis
- Central Nervous System Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach Riß, Germany.
| | - Wiebke Nissen
- Central Nervous System Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach Riß, Germany
| | - Boris Ferger
- Central Nervous System Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach Riß, Germany
| | - Roberto Arban
- Central Nervous System Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach Riß, Germany.
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Zhong W, Chebolu S, Darmani NA. Intracellular emetic signaling evoked by the L-type Ca 2+ channel agonist FPL64176 in the least shrew (Cryptotis parva). Eur J Pharmacol 2018; 834:157-168. [PMID: 29966616 DOI: 10.1016/j.ejphar.2018.06.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 06/09/2018] [Accepted: 06/28/2018] [Indexed: 12/20/2022]
Abstract
Ca2+ plays a major role in maintaining cellular homeostasis and regulates processes including apoptotic cell death and side-effects of cancer chemotherapy including vomiting. Currently we explored the emetic mechanisms of FPL64176, an L-type Ca2+ channel (LTCC) agonist with maximal emetogenic effect at its 10 mg/kg dose. FPL64176 evoked c-Fos immunoreactivity in shrew brainstem sections containing the vomit-associated nuclei, nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus. FPL64176 also increased phosphorylation of proteins ERK1/2, PKCα/βII and Akt in the brainstem. Moreover, their corresponding inhibitors (PD98059, GF 109203X and LY294002, respectively) reduced FPL64176-evoked vomiting. A 30 min subcutaneous (s.c.) pretreatment with the LTCC antagonist nifedipine (10 mg/kg) abolished FPL64176-elicited vomiting, c-Fos expression, and emetic effector phosphorylation. Ryanodine receptors (RyRs) and inositol trisphosphate receptors (IP3Rs) mediate intracellular Ca2+ release from the sarcoplasmic/endoplasmic reticulum. The RyR antagonist dantrolene (i.p.), or a combination of low doses of nifedipine and dantrolene, but not the IP3R antagonist 2-APB, significantly attenuated FPL64176-induced vomiting. The serotonin type 3 receptor (5-HT3R) antagonist palonosetron (s.c.), the neurokinin 1 receptor (NK1R) antagonist netupitant (i.p.) or a combination of non-effective doses of netupitant and palonosetron showed antiemetic potential against FPL64176-evoked vomiting. Serotonin (5-HT) and substance P immunostaining revealed FPL64176-induced emesis was accompanied by an increase in 5-HT but not SP-immunoreactivity in the dorsomedial subdivision of the NTS. These findings demonstrate that Ca2+ mobilization through LTCCs and RyRs, and subsequent emetic effector phosphorylation and 5-HT release play important roles in FPL64176-induced emesis which can be prevented by 5-HT3R and NK1R antagonists.
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Affiliation(s)
- Weixia Zhong
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States
| | - Seetha Chebolu
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States
| | - Nissar A Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States.
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Rubil S, Rössler OG, Thiel G. CREB, AP-1, ternary complex factors and MAP kinases connect transient receptor potential melastatin-3 (TRPM3) channel stimulation with increased c-Fos expression. Br J Pharmacol 2015; 173:305-18. [PMID: 26493679 DOI: 10.1111/bph.13372] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 10/08/2015] [Accepted: 10/14/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The rise in intracellular Ca(2+) stimulates the expression of the transcription factor c-Fos. Depending on the mode of entry of Ca(2+) into the cytosol, distinct signal transducers and transcription factors are required. Here, we have analysed the signalling pathway connecting a Ca(2+) influx via activation of transient receptor potential melastatin-3 (TRPM3) channels with enhanced c-Fos expression. EXPERIMENTAL APPROACH Transcription of c-Fos promoter/reporter genes that were integrated into the chromatin via lentiviral gene transfer was analysed in HEK293 cells overexpressing TRPM3. The transcriptional activation potential of c-Fos was measured using a GAL4-c-Fos fusion protein. KEY RESULTS The signalling pathway connecting TRPM3 stimulation with enhanced c-Fos expression requires the activation of MAP kinases. On the transcriptional level, three Ca(2+) -responsive elements, the cAMP-response element and the binding sites for the serum response factor (SRF) and AP-1, are essential for the TRPM3-mediated stimulation of the c-Fos promoter. Ternary complex factors are additionally involved in connecting TRPM3 stimulation with the up-regulation of c-Fos expression. Stimulation of TRPM3 channels also increases the transcriptional activation potential of c-Fos. CONCLUSIONS AND IMPLICATIONS Signalling molecules involved in connecting TRPM3 with the c-Fos gene are MAP kinases and the transcription factors CREB, SRF, AP-1 and ternary complex factors. As c-Fos constitutes, together with other basic region leucine zipper transcription factors, the AP-1 transcription factor complex, the results of this study explain TRPM3-induced activation of AP-1 and connects TRPM3 with the biological functions regulated by AP-1.
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Affiliation(s)
- Sandra Rubil
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
| | - Oliver G Rössler
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
| | - Gerald Thiel
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
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4
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Hess EJ, Jinnah H. Mouse Models of Dystonia. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00027-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Untethering the nuclear envelope and cytoskeleton: biologically distinct dystonias arising from a common cellular dysfunction. Int J Cell Biol 2012; 2012:634214. [PMID: 22611399 PMCID: PMC3352338 DOI: 10.1155/2012/634214] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 12/12/2011] [Accepted: 01/08/2012] [Indexed: 12/31/2022] Open
Abstract
Most cases of early onset DYT1 dystonia in humans are caused by a GAG deletion in the TOR1A gene leading to loss of a glutamic acid (ΔE) in the torsinA protein, which underlies a movement disorder associated with neuronal dysfunction without apparent neurodegeneration. Mutation/deletion of the gene (Dst) encoding dystonin in mice results in a dystonic movement disorder termed dystonia musculorum, which resembles aspects of dystonia in humans. While torsinA and dystonin proteins do not share modular domain architecture, they participate in a similar function by modulating a structural link between the nuclear envelope and the cytoskeleton in neuronal cells. We suggest that through a shared interaction with the nuclear envelope protein nesprin-3α, torsinA and the neuronal dystonin-a2 isoform comprise a bridge complex between the outer nuclear membrane and the cytoskeleton, which is critical for some aspects of neuronal development and function. Elucidation of the overlapping roles of torsinA and dystonin-a2 in nuclear/endoplasmic reticulum dynamics should provide insights into the cellular mechanisms underlying the dystonic phenotype.
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Kakazu Y, Koh JY, Ho KWD, Gonzalez-Alegre P, Harata NC. Synaptic vesicle recycling is enhanced by torsinA that harbors the DYT1 dystonia mutation. Synapse 2012; 66:453-64. [PMID: 22213465 DOI: 10.1002/syn.21534] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 11/20/2011] [Accepted: 12/17/2011] [Indexed: 11/08/2022]
Abstract
Early-onset generalized dystonia, DYT1, is caused by a mutation in the gene encoding the evolutionarily conserved AAA+ ATPase torsinA. Synaptic abnormalities have been implicated in DYT1 dystonia, but the details of the synaptic pathophysiology are only partially understood. Here, we demonstrate a novel role for torsinA in synaptic vesicle recycling, using cultured hippocampal neurons from a knock-in mouse model of DYT1 dystonia (ΔE-torsinA) and live-cell imaging with styryl FM dyes. Neurons from heterozygous ΔE-torsinA mice released a larger fraction of the total recycling pool (TRP) during a single round of electrical stimulation than did wild-type neurons. Moreover, when the neurons were subjected to prior high activity, the time course of release was shortened. In neurons from homozygous mice, these enhanced exocytosis phenotypes were similar, but in addition the size of the TRP was reduced. Notably, when release was triggered by applying a calcium ionophore rather than electrical stimuli, neither a single nor two ΔE-torsinA alleles affected the time course of release. Thus, the site of action of ΔE-torsinA is at or upstream of the rise in calcium concentration in nerve terminals. Our results suggest that torsinA regulates synaptic vesicle recycling in central neurons. They also indicate that this regulation is influenced by neuronal activity, further supporting the idea that synaptic abnormalities contribute to the pathophysiology of DYT1 dystonia.
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Affiliation(s)
- Yasuhiro Kakazu
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
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Tfelt-Hansen P, Tfelt-Hansen J. Verapamil for cluster headache. Clinical pharmacology and possible mode of action. Headache 2009; 49:117-25. [PMID: 19125880 DOI: 10.1111/j.1526-4610.2008.01298.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Verapamil is used mainly in cardiovascular diseases. High-dose verapamil (360-720 mg) is, however, currently the mainstay in the prophylactic treatment of cluster headache. The oral pharmacokinetics are variable. The pharmacodynamic effect of verapamil, the effect on blood pressure, also varies considerably among subjects. The dose of verapamil used for cluster headache is approximately double the dose used in cardiovascular disease, most likely because verapamil is a substrate for the efflux transporter P-glycoprotein in the blood-brain barrier. The access of verapamil to the central nervous system is therefore limited. The clinical use of verapamil in cluster headache is reviewed and several relevant drug interactions are mentioned. Finally, its possible mode of action in cluster headache is discussed. The effect of verapamil in cluster headache most likely takes place in the hypothalamus.Verapamil is an L-type calcium channel blocker but it is also a blocker of other calcium channels (T-, P-, and possibly N- and Q-type Ca(2+) channels) and the human ether-a-go-go-related gene potassium channel. With so many different actions of verapamil, it is impossible at the present time to single out a certain mode of action of the drug in cluster headache.
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Affiliation(s)
- Peer Tfelt-Hansen
- Danish Headache Centre, Department of Neurology, University of Copenhagen, Glostrup Hospital, Glostrup, Denmark
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Guo YP, Sun X, Li C, Wang NQ, Chan YS, He J. Corticothalamic synchronization leads to c-fos expression in the auditory thalamus. Proc Natl Acad Sci U S A 2007; 104:11802-7. [PMID: 17606925 PMCID: PMC1913871 DOI: 10.1073/pnas.0701302104] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study, we investigated the relationship between c-fos expression in the auditory thalamus and corticofugal activation. The contribution of neurotransmitters and related receptors, the involvement of thalamic reticular nucleus (TRN), and the role of neuronal firing patterns in this process were also examined. The principal nuclei of the medial geniculate body (MGB) showed c-fos expression when the auditory cortex (AC) was activated by direct injection of bicuculline methobromide. However, no expression was detectable with acoustic stimuli alone. This indicated that c-fos expression in the principal nuclei of the MGB was triggered by the corticofugal projection. c-fos expression could be elicited in the MGB by direct injection of glutamate. Direct administration of acetylcholine, alternatively, had no effect. Bicuculline methobromide injection in the AC also triggered synchronized oscillatory activities sequentially in the AC and MGB. Cortically induced c-fos expression in the MGB was not mediated by a pathway involving the TRN because it remained intact after a TRN lesion with kainic acid. The present results also conclude that c-fos expression is not simply associated with firing rate, but also with neuronal firing pattern. Burst firings that are synchronized with the cortical oscillations are proposed to lead to c-fos expression in the principal nuclei of the MGB.
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Affiliation(s)
- Yi Ping Guo
- *Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; and
| | - Xia Sun
- *Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; and
- Department of Physiology and Research Centre of Heart, Brain, Hormone, and Healthy Aging, LKS Faculty of Medicine, University of Hong Kong, Sassoon Road, Hong Kong, China
| | - Chuan Li
- *Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; and
| | - Ning Qian Wang
- *Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; and
| | - Ying-Shing Chan
- Department of Physiology and Research Centre of Heart, Brain, Hormone, and Healthy Aging, LKS Faculty of Medicine, University of Hong Kong, Sassoon Road, Hong Kong, China
| | - Jufang He
- *Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; and
- To whom correspondence should be addressed. E-mail:
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Kasim S, Blake BL, Fan X, Chartoff E, Egami K, Breese GR, Hess EJ, Jinnah HA. The role of dopamine receptors in the neurobehavioral syndrome provoked by activation of L-type calcium channels in rodents. Dev Neurosci 2006; 28:505-17. [PMID: 17028428 PMCID: PMC2951315 DOI: 10.1159/000095113] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Accepted: 11/16/2005] [Indexed: 11/19/2022] Open
Abstract
In rodents, activation of L-type calcium channels with +/-BayK 8644 causes an unusual behavioral syndrome that includes dystonia and self-biting. Prior studies have linked both of these behaviors to dysfunction of dopaminergic transmission in the striatum. The current studies were designed to further elucidate the relationship between +/-BayK 8644 and dopaminergic transmission in the expression of the behavioral syndrome. The drug does not appear to release presynaptic dopamine stores, since microdialysis of the striatum revealed dopamine release was unaltered by +/-BayK 8644. In addition, the behaviors were preserved or even exaggerated in mice or rats with virtually complete dopamine depletion. On the other hand, pretreatment of mice with D(3) or D(1/5) dopamine receptor antagonists attenuated the behavioral effects of +/-BayK 8644, while pretreatment with D(2) or D(4) antagonists had no effect. In D(3) receptor knockout mice, +/-BayK 8644 elicited both dystonia and self-biting, but these behaviors were less severe than in matched controls. In D(1) receptor knockout mice, behavioral responses to +/-BayK 8644 appeared exaggerated. These results argue that the behavioral effects of +/-BayK 8644 are not mediated by a presynaptic influence. Instead, the behaviors appear to result from a postsynaptic activation of the drug, which does not require but can be modified by D(3) or D(1/5) receptors.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Calcium Channel Agonists/pharmacology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Central Nervous System Stimulants/pharmacology
- Corpus Striatum/drug effects
- Corpus Striatum/metabolism
- Corpus Striatum/physiopathology
- Disease Models, Animal
- Dopamine/metabolism
- Dopamine Antagonists/pharmacology
- Dystonia/chemically induced
- Dystonia/metabolism
- Dystonia/physiopathology
- Female
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine/drug effects
- Receptors, Dopamine/genetics
- Receptors, Dopamine/metabolism
- Receptors, Dopamine D1/drug effects
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D3/drug effects
- Receptors, Dopamine D3/genetics
- Receptors, Dopamine D3/metabolism
- Self-Injurious Behavior/chemically induced
- Self-Injurious Behavior/metabolism
- Self-Injurious Behavior/physiopathology
- Synaptic Membranes/drug effects
- Synaptic Membranes/genetics
- Synaptic Membranes/metabolism
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- Syndrome
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Affiliation(s)
- Suhail Kasim
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21287, USA
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Blake BL, Muehlmann AM, Egami K, Breese GR, Devine DP, Jinnah HA. Nifedipine suppresses self-injurious behaviors in animals. Dev Neurosci 2006; 29:241-50. [PMID: 17047321 PMCID: PMC2951318 DOI: 10.1159/000096414] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 04/12/2006] [Indexed: 11/19/2022] Open
Abstract
Self-injurious behavior is a common problem in many developmental disorders. The neurobiology of this behavior is not well understood, but the differing behavioral manifestations and associations with different disorders suggest that the underlying biological mechanisms are heterogeneous. The behavioral and biological heterogeneity is also evident in several animal models, where different manifestations can be provoked under different experimental conditions. Identifying commonalities among the different mechanisms is likely to be helpful in the design of treatments useful for the broadest populations of patients. The current studies reveal that nifedipine suppresses self-injurious behavior in 4 unrelated animal models: acute administration of high doses of +/-BayK 8644 or methamphetamine in mice, dopamine agonist treatment in rats with lesions of dopamine pathways during early development and repeated administration of pemoline in rats. The effect of nifedipine does not appear to be due to nonspecific mechanisms, such as sedation, since other classes of behaviors are unaffected or exaggerated. These results suggest that nifedipine may target a common biological mechanism in the expression of self-injurious behavior, and they suggest it should be considered in the treatment of self-injury in humans.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
- Animals
- Behavior, Animal/drug effects
- Calcium Channel Agonists
- Calcium Channel Blockers/pharmacology
- Central Nervous System Stimulants
- Disease Models, Animal
- Female
- Male
- Methamphetamine
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Nifedipine/pharmacology
- Oxidopamine
- Pemoline
- Pregnancy
- Rats
- Rats, Long-Evans
- Rats, Sprague-Dawley
- Self-Injurious Behavior/chemically induced
- Self-Injurious Behavior/drug therapy
- Sympatholytics
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Affiliation(s)
- Bonita L Blake
- Department of Psychiatry, University of North Carolina, Chapel Hill, USA
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Nakai S, Matsunaga W, Ishida Y, Isobe KI, Shirokawa T. Effects of BDNF infusion on the axon terminals of locus coeruleus neurons of aging rats. Neurosci Res 2006; 54:213-9. [PMID: 16406148 DOI: 10.1016/j.neures.2005.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 12/06/2005] [Accepted: 12/06/2005] [Indexed: 12/29/2022]
Abstract
Using in vivo electrophysiological techniques and continuous local infusion methods, we examined the effects of brain-derived neurotrophic factor (BDNF) and its specific antibody (anti-BDNF) on the noradrenergic axon terminals of the locus coeruleus (LC) neurons in the frontal cortex of aging rats. Recently, we observed that LC neurons with multiple-threshold antidromic responses (multi-threshold LC neurons) increased critically between 15 and 17 months of age. To examine whether the BDNF is involved in this change occurred in the aging brain, we continuously infused BDNF into the frontal cortex for 14 days. Exogenous BDNF produced a marked increase in the multi-threshold LC neurons in the 13-month-old brain, accompanied with a decrease in threshold current. However, no morphological change in the noradrenergic axons was observed in the BDNF-infused cortex. In contrast, infusion of anti-BDNF led to a dose-dependent reduction of the multi-threshold LC neurons in the 19-month-old brain, accompanied with an increase in threshold current. These findings suggest that BDNF may contribute to functional changes in the presynaptic axon terminals of LC neurons in the aging brain.
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Affiliation(s)
- Sadamu Nakai
- Department of Basic Gerontology, National Center for Geriatrics and Gerontology, Obu 474-8522, Japan
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12
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Hetzenauer A, Sinnegger-Brauns MJ, Striessnig J, Singewald N. Brain activation pattern induced by stimulation of L-type Ca2+-channels: Contribution of CaV1.3 and CaV1.2 isoforms. Neuroscience 2006; 139:1005-15. [PMID: 16542784 DOI: 10.1016/j.neuroscience.2006.01.059] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 01/25/2006] [Accepted: 01/27/2006] [Indexed: 10/24/2022]
Abstract
Ca(V)1.2 and Ca(V)1.3, are the main dihydropyridine-sensitive L-type calcium channel isoforms in the brain. To reveal the contribution of each isoform to the neuronal activation pattern elicited by the dihydropyridine L-type calcium channel activator BayK 8644, we utilized Fos expression as a marker of neuronal activation in mutant mice (Ca(V)1.2(DHP-/-) mice) expressing dihydropyridine-insensitive Ca(V)1.2 L-type calcium channels. BayK 8644-treated wildtype mice displayed intense and widespread Fos expression throughout the neuroaxis in 77 of 80 brain regions quantified. The Fos response in Ca(V)1.2(DHP-/-) mice was greatly attenuated or absent in most of these areas, suggesting that a major part of the widespread Fos induction including most cortical areas was mediated by Ca(V)1.2 L-type calcium channels. BayK 8644-induced Fos expression in Ca(V)1.2(DHP-/-) mice indicating predominantly Ca(V)1.3 L-type calcium channel-mediated activation was noted in more restricted neuronal populations (20 of 80), in particular in the central amygdala, the bed nucleus of the stria terminalis, paraventricular hypothalamic nucleus, lateral preoptic area, locus coeruleus, lateral parabrachial nucleus, central nucleus of the inferior colliculus, and nucleus of the solitary tract. Our data indicate that selective stimulation of other than Ca(V)1.2 L-type calcium channels, mostly Ca(V)1.3, causes neuronal activation in a specific set of mainly limbic, hypothalamic and brainstem areas, which are associated with functions including integration of emotion-related behavior. Hence, selective modulation of Ca(V)1.3 L-type calcium channels could represent a novel (pharmacotherapeutic) tool to influence these CNS functions.
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Affiliation(s)
- A Hetzenauer
- Leopold-Franzens-University Innsbruck, Institute of Pharmacy, Department of Pharmacology and Toxicology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Peter-Mayr-Str. 1, A-6020 Innsbruck, Austria
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13
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Abstract
Dystonia is a prevalent neurological disorder characterized by abnormal co-contractions of antagonistic muscle groups that produce twisting movements and abnormal postures. The disorder may be inherited, arise sporadically, or result from brain insult. Dystonia is a heterogeneous disorder because patients may exhibit focal or generalized symptoms associated with abnormalities in many brain regions including basal ganglia and cerebellum. Elucidating the pathogenic mechanisms underlying dystonia has therefore been challenging. Animal models of dystonia exhibit similar heterogeneity and are useful for understanding pathogenesis. The neurochemical and neurophysiological abnormalities in rodents with idiopathic generalized dystonia suggest that dysfunctional output from basal ganglia, cerebellum, or from multiple systems is the cause of motor dysfunction. Findings from drug- or toxin-induced dystonia in rodents and nonhuman primates mirror the genetic models. The parallels between dystonia in humans and animals suggest that the models will continue to prove useful in determining pathogenesis. Furthermore, detailed characterization of the existing models of dystonia and the development of new models hold promise for the identification of novel therapeutics.
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Affiliation(s)
- Robert S Raike
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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