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Hirata Y, Nomura K, Kato D, Tachibana Y, Niikura T, Uchiyama K, Hosooka T, Fukui T, Oe K, Kuroda R, Hara Y, Adachi T, Shibasaki K, Wake H, Ogawa W. A Piezo1/KLF15/IL-6 axis mediates immobilization-induced muscle atrophy. J Clin Invest 2022; 132:1-13. [PMID: 35290243 PMCID: PMC9159676 DOI: 10.1172/jci154611] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 03/01/2022] [Indexed: 11/17/2022] Open
Abstract
Although immobility is a common cause of muscle atrophy, the mechanism underlying this causality is unclear. We here show that Krüppel-like factor 15 (KLF15) and IL-6 are upregulated in skeletal muscle of limb-immobilized mice and that mice with KLF15 deficiency in skeletal muscle or with systemic IL-6 deficiency are protected from immobility-induced muscle atrophy. A newly developed Ca2+ bioimaging revealed that the cytosolic Ca2+ concentration ([Ca2+]i) of skeletal muscle is reduced to below the basal level by immobilization, which is associated with the downregulation of Piezo1. Acute disruption of Piezo1 in skeletal muscle induced Klf15 and Il6 expression as well as muscle atrophy, which was prevented by antibodies against IL-6. A role for the Piezo1/KLF15/IL-6 axis in immobility-induced muscle atrophy was validated in human samples. Our results thus uncover a paradigm for Ca2+ signaling in that a decrease in [Ca2+]i from the basal level triggers a defined biological event.
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Affiliation(s)
- Yu Hirata
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazuhiro Nomura
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Daisuke Kato
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshihisa Tachibana
- Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takahiro Niikura
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kana Uchiyama
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tetsuya Hosooka
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoaki Fukui
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Keisuke Oe
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ryosuke Kuroda
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuji Hara
- Department of Integrative Physiology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Takahiro Adachi
- Department of Precision Health, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Koji Shibasaki
- Laboratory of Neurochemistry, Graduate School of Human Health Science, University of Nagasaki, Nagasaki, Japan
| | - Hiroaki Wake
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Wataru Ogawa
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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Di T, Zhang S, Hong J, Zhang T, Chen L. Hyperactivity of Hypothalamic-Pituitary-Adrenal Axis Due to Dysfunction of the Hypothalamic Glucocorticoid Receptor in Sigma-1 Receptor Knockout Mice. Front Mol Neurosci 2017; 10:287. [PMID: 28932185 PMCID: PMC5592243 DOI: 10.3389/fnmol.2017.00287] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/24/2017] [Indexed: 01/07/2023] Open
Abstract
Sigma-1 receptor knockout (σ1R-KO) mice exhibit a depressive-like phenotype. Because σ1R is highly expressed in the neuronal cells of hypothalamic paraventricular nuclei (PVN), this study investigated the influence of σ1R deficiency on the regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Here, we show that the levels of basal serum corticosterone (CORT), adrenocorticotropic hormone (ACTH) and corticotrophin releasing factor (CRF) as well as the level of CRF mRNA in PVN did not significantly differ between adult male σ1R-KO mice and wild-type (WT) mice. Acute mild restraint stress (AMRS) induced a higher and more sustainable increase in activity of HPA axis and CRF expression in σ1R-KO mice. Percentage of dexamethasone (Dex)-induced reduction in level of CORT was markedly attenuated in σ1R-/- mice. The levels of glucocorticoid receptor (GR) and protein kinase C (PKC) phosphorylation were reduced in the PVN of σ1R-KO mice and σ1R antagonist NE100-treated WT mice. The exposure to AMRS in σ1R-KO mice induced a stronger phosphorylation of cAMP-response element binding protein (CREB) in PVN than that in WT mice. Intracerebroventricular (i.c.v.) injection of PKC activator PMA for 3 days in σ1R-KO mice not only recovered the GR phosphorylation and the percentage of Dex-reduced CORT but also corrected the AMRS-induced hyperactivity of HPA axis and enhancement of CRF mRNA and CREB phosphorylation. Furthermore, the injection (i.c.v.) of PMA in σ1R-KO mice corrected the prolongation of immobility time in forced swim test (FST) and tail suspension test (TST). These results indicate that σ1R deficiency causes down-regulation of GR by reducing PKC phosphorylation, which attenuates GR-mediated feedback inhibition of HPA axis and facilitates the stress response of HPA axis leading to the production of depressive-like behaviors.
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Affiliation(s)
- Tingting Di
- State Key Laboratory of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Suyun Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical UniversityNanjing, China
| | - Juan Hong
- State Key Laboratory of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Tingting Zhang
- Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Ling Chen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
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Zhang T, Chen T, Chen P, Zhang B, Hong J, Chen L. MPTP-Induced Dopamine Depletion in Basolateral Amygdala via Decrease of D2R Activation Suppresses GABA A Receptors Expression and LTD Induction Leading to Anxiety-Like Behaviors. Front Mol Neurosci 2017; 10:247. [PMID: 28824377 PMCID: PMC5545577 DOI: 10.3389/fnmol.2017.00247] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/24/2017] [Indexed: 11/13/2022] Open
Abstract
Anxiety disorders commonly occur in Parkinson’s disease. Using field potential recording and patch-clamp recording, we evaluated influence of MPTP-reduced dopaminergic afferent in basolateral amygdala (BLA), a main region for affective regulation, on excitatory–inhibitory circuits and synaptic plasticity. Field excitatory post-synaptic potential (fEPSP) slopes at external capsule-BLA synapses were increased in MPTP-mice with decreases in paired-pulse facilitation and long-term potentiation amplitude, which were corrected by bath-application of D2R agonist quinpirole or cannabinoid type 1 receptors agonist WIN55,212-2, but not D1R agonist SKF38393. Compared to single waveform fEPSP in control mice, a multi-spike waveform fEPSP was observed in MPTP-mice with prolongation of duration and an increase in paired-pulse inhibition, which were recovered by BLA-injection of quinpirole for 2 days rather than bath-application. Density of GABA-evoked current (IGABA) in BLA principal neurons and GABAAR-α2 subunit expression were reduced in MPTP-mice, which were recovered by administration of quinpirole. Decline of PKC phosphorylation in BLA of MPTP-mice was corrected by bath-application of quinpirole, but not SKF38393. In MPTP-mice, BLA-injection of quinpirole or PKC activator PMA could recover GABAAR expression, which was sensitive to PKC inhibitor GF109203X. The impairment of long-term depression (LTD) in MPTP-mice was rescued by bath-application of GABAAR agonist muscimol or BLA-injection of quinpirole and PMA. Finally, BLA-injection of muscimol, quinpirole or PMA relieved anxiety-like behaviors in MPTP-mice. The results indicate that the MPTP-induced dopamine depletion in BLA principal neurons through reducing D2R-mediated PKC phosphorylation suppresses GABAAR expression and activity, which impairs GABAAR-mediated inhibition and LTD induction leading to anxiety-like behaviors.
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Affiliation(s)
- Tingting Zhang
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Tingting Chen
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Peipei Chen
- Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Baofeng Zhang
- Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Juan Hong
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
| | - Ling Chen
- State Key Lab of Reproductive Medicine, Nanjing Medical UniversityNanjing, China.,Department of Physiology, Nanjing Medical UniversityNanjing, China
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Abrial E, Etievant A, Bétry C, Scarna H, Lucas G, Haddjeri N, Lambás-Señas L. Protein kinase C regulates mood-related behaviors and adult hippocampal cell proliferation in rats. Prog Neuropsychopharmacol Biol Psychiatry 2013; 43:40-8. [PMID: 23228462 DOI: 10.1016/j.pnpbp.2012.11.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/08/2012] [Accepted: 11/18/2012] [Indexed: 12/16/2022]
Abstract
The neurobiological mechanisms underlying the pathophysiology and therapeutics of bipolar disorder are still unknown. In recent years, protein kinase C (PKC) has emerged as a potential key player in mania. To further investigate the role of this signaling system in mood regulation, we examined the effects of PKC modulators in behavioral tests modeling several facets of bipolar disorder and in adult hippocampal cell proliferation in rats. Our results showed that a single injection of the PKC inhibitors tamoxifen (80 mg/kg, i.p.) and chelerythrine (3 mg/kg, s.c.) attenuated amphetamine-induced hyperlocomotion and decreased risk-taking behavior, supporting the efficacy of PKC blockade in acute mania. Moreover, chronic exposure to tamoxifen (10 mg/kg/day, i.p., for 14 days) or chelerythrine (0.3 mg/kg/day, s.c., for 14 days) caused depressive-like behavior in the forced swim test, and resulted in a reduction of cell proliferation in the dentate gyrus of the hippocampus. Finally, we showed that, contrary to the PKC inhibitors, the PKC activator phorbol 12-myristate 13-acetate (PMA) enhanced risk-taking behavior and induced an antidepressant-like effect. Taken together, these findings support the involvement of PKC in regulating opposite facets of bipolar disorder, and emphasize a major role for PKC in this disease.
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Selvatici R, Congestrì F, Marzola G, Guerrini R, Siniscalchi A, Spisani S. Anti-inflammatory and analgesic effects displayed by peptides derived from PKI55 protein, an endogenous protein kinase C inhibitor. Naunyn Schmiedebergs Arch Pharmacol 2010; 382:193-9. [PMID: 20644913 DOI: 10.1007/s00210-010-0536-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 07/05/2010] [Indexed: 11/25/2022]
Abstract
We recently characterized the PKI55 protein as an endogenous protein kinase C (PKC) inhibitor and investigated, in vitro, the potential anti-inflammatory actions of its N-terminal peptides 1-16 (peptide 5), 1-8 (peptide 8) and 1-5 (peptide 9). We showed their ability to inhibit chemotaxis in human polymorphonuclear leukocytes activated by the N-formyl tripeptide for-Met-Leu-Phe-OMe. In this work, we evaluated the anti-inflammatory and the analgesic effects of the selected peptides by in vivo experiments carried out in the mouse. The peptides 5, 8 and 9 (0.1 and 10 nmol i.c.v.) were effective in both the parameters chosen to test the anti-inflammatory activity, i.e., the xylene-induced ear edema and the acetic acid-induced infiltration of neutrophils in the peritoneal cavity. In addition, they displayed analgesic effect, evaluated by the acetic acid-induced writhing test. All the peptides' effects were shared by the reference compounds, dexamethasone and indomethacin (10 mg kg(-1) i.p.), but not by the 9-scramble peptide (10 nmol i.c.v.). The peptide 9, which represents the shortest active sequence of the PKI55 protein, was tested in the ear edema model even following intraperitoneal (i.p.) administration and proved to be effective in the range doses 3-30 mg kg(-1). Moreover, an increase in plasma corticosterone levels was detected in mice treated with the peptide 9, but not with the 9-scramble peptide (both at 10 nmol i.c.v.). The anti-inflammatory and analgesic effects of the PKI55-derived synthetic peptides, possibly related both to PKC inhibition and hypothalamic-pituitary-adrenal axis activation, deserve further investigation in view of potential therapeutic exploitation.
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Affiliation(s)
- Rita Selvatici
- Department of Experimental and Diagnostic Medicine, Medical Genetics Section, University of Ferrara, Ferrara, Italy
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Kwon MS, Seo YJ, Choi SM, Choi HW, Jung JS, Park SH, Suh HW. The differential effects of single or repeated restraint stress on kainic acid-induced neuronal death in the hippocampal CA3 region: the role of glucocorticoid and various signal molecules. J Neurochem 2007; 103:1530-41. [PMID: 17727630 DOI: 10.1111/j.1471-4159.2007.04865.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of stress mediators following the stress period and addition time is a controversial issue until now. Thus, we aim to clarify the differential effects of single restraint stress (SS) or repeated restraint stress (RS) on kainic acid (KA)-induced neuronal death especially as addressing not only the role of glucocorticoid (Gc) and its receptor but also the signal pathway leading to cAMP response element binding protein phosphorylation (pCREB) and its functional role during stress. In the present study, we found that although RS did not show any difference on serum Gc level and hippocampal Gc receptor level compared to SS, SS exacerbated KA-induced neuronal death in hippocampal CA3 region, but RS did not. Moreover, pre-treatment with RU 38486 (Gc receptor antagonist) abolished the effect of SS on KA-induced neuronal death without an effect on KA toxicity itself. Furthermore, RS aggravates KA-induced neuronal death when CREB phosphorylation was deprived by KN-93 (calcium/calmodulin-dependent protein kinase II inhibitor). However, other signal molecules inhibitors such as PD98059 (MEK1/2 inhibitor) and SP600125 (p-p38 inhibitor) have no effect on KA-induced neuronal death after RS although these signal molecule were increased during SS or RS. These findings suggest that pCREB expression via calcium/calmodulin-dependent protein kinase II phosphorylation during RS comprise one of the balancers against Gc induced by stress.
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Affiliation(s)
- Min-Soo Kwon
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Gangwon-do, South Korea
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McNamara RK, Ostrander M, Abplanalp W, Richtand NM, Benoit SC, Clegg DJ. Modulation of phosphoinositide-protein kinase C signal transduction by omega-3 fatty acids: implications for the pathophysiology and treatment of recurrent neuropsychiatric illness. Prostaglandins Leukot Essent Fatty Acids 2006; 75:237-57. [PMID: 16935483 DOI: 10.1016/j.plefa.2006.07.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The phosphoinositide (PI)-protein kinase C (PKC) signal transduction pathway is initiated by pre- and postsynaptic Galphaq-coupled receptors, and regulates several clinically relevant neurochemical events, including neurotransmitter release efficacy, monoamine receptor function and trafficking, monoamine transporter function and trafficking, axonal myelination, and gene expression. Mounting evidence for PI-PKC signaling hyperactivity in the peripheral (platelets) and central (premortem and postmortem brain) tissues of patients with schizophrenia, bipolar disorder, and major depressive disorder, coupled with evidence that PI-PKC signal transduction is down-regulated in rat brain following chronic, but not acute, treatment with antipsychotic, mood-stabilizer, and antidepressant medications, suggest that PI-PKC hyperactivity is central to an underlying pathophysiology. Evidence that membrane omega-3 fatty acids act as endogenous antagonists of the PI-PKC signal transduction pathway, coupled with evidence that omega-3 fatty acid deficiency is observed in peripheral and central tissues of patients with schizophrenia, bipolar disorder, and major depressive disorder, support the hypothesis that omega-3 fatty acid deficiency may contribute to elevated PI-PKC activity in these illnesses. The data reviewed in this paper outline a potential molecular mechanism by which omega-3 fatty acids could contribute to the pathophysiology and treatment of recurrent neuropsychiatric illness.
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Affiliation(s)
- Robert K McNamara
- Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0559, USA.
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Breese GR, Knapp DJ, Overstreet DH. Stress sensitization of ethanol withdrawal-induced reduction in social interaction: inhibition by CRF-1 and benzodiazepine receptor antagonists and a 5-HT1A-receptor agonist. Neuropsychopharmacology 2004; 29:470-82. [PMID: 12955093 PMCID: PMC2898195 DOI: 10.1038/sj.npp.1300282] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2003] [Revised: 06/10/2003] [Accepted: 06/13/2003] [Indexed: 11/09/2022]
Abstract
Repeated withdrawals from chronic ethanol sensitize the withdrawal-induced reduction in social interaction behaviors. This study determined whether stress might substitute for repeated withdrawals to facilitate withdrawal-induced anxiety-like behavior. When two 1-h periods of restraint stress were applied at 1-week intervals to rats fed control diet, social interaction was reduced upon withdrawal from a subsequent 5-day exposure to ethanol diet. Neither this ethanol exposure alone nor exposure to three restraint stresses alone altered this measure of anxiety. Further, the repeatedly stressed singly withdrawn rats continued to exhibit a reduction in social interaction 16 days later, upon withdrawal from re-exposure to 5 days of chronic ethanol, consistent with a persistent adaptation by the multiple-stress/withdrawal protocol. Weekly administration of corticosterone in place of stress induced no significant change in social interaction upon withdrawal from the single chronic ethanol exposure, indicative that corticoid release is not responsible for the stress-induced reduction in anxiety-like behavior during withdrawal. In the multiple-withdrawal protocol, stress applied during withdrawal from voluntary ethanol drinking by P-rats facilitated ethanol drinking sufficiently, to induce a withdrawal-induced reduction in social interaction. Administration of a CRF-1 receptor antagonist, a benzodiazepine receptor antagonist, or a 5-HT(1A) receptor agonist prior to each stress minimized sensitization of the withdrawal-induced reduction in anxiety-like behavior. Since these pharmacological consequences on the induction of anxiety-like behavior following the stress/withdrawal protocol are like those previously seen when these drug treatments were given prior to multiple withdrawals, evidence is provided that repeated stresses and multiple withdrawals sensitize the withdrawal reduction in social interaction by similar central adaptive mechanisms.
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Affiliation(s)
- George R Breese
- Department of Psychiatry, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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Kim DH, Moon YS, Jung JS, Min SK, Son BK, Suh HW, Song DK. Effects of ginseng saponin administered intraperitoneally on the hypothalamo-pituitary-adrenal axis in mice. Neurosci Lett 2003; 343:62-6. [PMID: 12749998 DOI: 10.1016/s0304-3940(03)00300-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Intraperitoneal injection of ginseng total saponin (GTS; 5 and 20 mg/kg) raised plasma corticosterone levels in mice. However, interestingly, pretreatment of animals with the same doses of GTS (5 and 20 mg/kg) significantly attenuated the immobilization stress-induced increase in plasma corticosterone levels. Of the ginsenosides Rb(1), Rb(2), Rc, Rd, Re, Rf, Rg(1), 20(S)-Rg(3), and 20(R)-Rg(3) injected intraperitoneally at doses of 0.1-2 mg/kg, Rc (2 mg/kg) significantly inhibited the immobilization stress-induced increase in plasma corticosterone levels. GTS and Rc administered intraperitoneally did not affect the immobilization stress-induced elevation of plasma adrenocorticotropic hormone (ACTH) level. Pretreatment with GTS and Rc significantly attenuated the increase in plasma corticosterone levels induced by intraperitoneal injection of ACTH (30 microg/kg). These results suggest that GTS and Rc inhibit the immobilization stress-induced increase in plasma corticosterone levels by blocking ACTH action in the adrenal gland. Ginseng may be proposed to be useful for treatment of stress related disorders.
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Affiliation(s)
- Do-Hoon Kim
- Department of Psychiatry, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon, Kangwon-Do, 200-702, South Korea
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Tjurmina OA, Armando I, Saavedra JM, Goldstein DS, Murphy DL. Exaggerated adrenomedullary response to immobilization in mice with targeted disruption of the serotonin transporter gene. Endocrinology 2002; 143:4520-6. [PMID: 12446578 DOI: 10.1210/en.2002-220416] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study examined whether serotonin transporter (5-HTT) gene knockout influences adrenomedullary, sympathoneural, or hypothalamo-pituitary-adrenal responses to acute immobilization. In conscious, cannulated mice, arterial plasma concentrations of catecholamines, ACTH, and corticosterone were measured at baseline and after 15 min of immobilization. Tissue levels of serotonin (5-HT), catecholamines, and hormones were also measured in pituitary and adrenal glands. At baseline, adrenal and pituitary 5-HT concentrations in knockout (5-HTT(-/-)) mice were markedly lower than those in littermate control (5-HTT(+/+)) mice, whereas the groups did not differ in levels of catecholamines or hormones in plasma or tissue. Immobilization increased plasma levels of catecholamines, ACTH, and corticosterone in all genotypes. 5-HTT(-/-) mice had exaggerated responses of plasma epinephrine to immobilization and significant reductions in adrenal epinephrine, norepinephrine, and 5-HT contents compared with values in littermate controls. Pituitary ACTH was significantly reduced after immobilization in 5-HTT(-/-) mice only, but increases in plasma ACTH and corticosterone levels did not differ between genotypes. The results suggest that one 5-HTT function is to restrain adrenomedullary activation in response to immobilization. Exaggerated adrenomedullary responses seem to be an autonomic correlate of the anxiety-like behaviors in 5-HTT knockout mice.
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Affiliation(s)
- Olga A Tjurmina
- Laboratory of Clinical Science, National Institute of Mental Health, and Clinical Neurocardiology Section, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Perera T, Lisanby SH, Sackheim HA. Protein kinase a in major depression: the link between hypothalamic-pituitary-adrenal axis hyperactivity and neurogenesis. CNS Spectr 2001; 6:565-8, 571-2. [PMID: 15573020 DOI: 10.1017/s1092852900002108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The latest and most generative biological theories of major depression center on two major hypotheses. The first focuses on the concept that hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis leads to many of the pathological changes in the brain that accompany major depression. The second posits that neurogenesis leads to the repair of depression-related injuries. These two hypotheses are complementary: the former alludes to the etiology or consequences of depression, while the latter suggests mechanisms of antidepressant action. Significant crosstalk occurs between these two systems at many levels. Protein kinase A (PKA) may play an important role in this crosstalk at the intracellular level of signaling cascades. PKA is involved in the formation of long-term potentiation and fear conditioning in response to stress. Chronic stress leads to the suppression of hippocampal activity, which may cause the hyperactivity of the HPA axis during melancholic depression. PKA is also involved in the stimulation of hippocampal neurogenesis after antidepressant treatment. In theory, neurogenesis may lead to the restoration of hippocampal function, and this may be the mechanism that leads to antidepressant-mediated normalization of HPA hyperactivity. Thus, PKA is active during processes that potentially lead to depression and other processes that lead to the resolution of the illness. These opposing processes may be mediated by separate PKA isozymes that activate two distinct pathways. This review highlights the dual role of this enzyme in two biological hypotheses pertaining to depression and its treatment.
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Affiliation(s)
- T Perera
- Department of Psychiatry, Columbia University, New York, NY, USA.
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