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Zelek-Molik A, Costanzi M, Rafa-Zabłocka K, Kreiner G, Roman A, Vetulani J, Rossi-Arnaud C, Cestari V, Nalepa I. Fear memory-induced alterations in the mRNA expression of G proteins in the mouse brain and the impact of immediate posttraining treatment with morphine. Prog Neuropsychopharmacol Biol Psychiatry 2019; 93:221-231. [PMID: 30953677 DOI: 10.1016/j.pnpbp.2019.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 10/27/2022]
Abstract
Disturbances in fear-evoked signal transduction in the hippocampus (HP), the nuclei of the amygdala (AMY), and the prefrontal cortex (PFC) underlie anxiety-related disorders. However, the molecular mechanisms underlying these effects remain elusive. Heterotrimeric G proteins (GPs) are divided into the following four families based on the intracellular activity of their alpha subunit (Gα): Gα(s) proteins stimulate cyclic AMP (cAMP) generation, Gα(i/o) proteins inhibit the cAMP pathway, Gα(q/11) proteins increase the intracellular Ca++ concentration and the inositol trisphosphate level, and Gα(12/13) proteins activate monomeric GP-Rho. In the present study, we assessed the effects of a fear memory procedure on the mRNA expression of the Gα subunits of all four GP families in the HP, AMY and PFC. C57BL/6 J mice were subjected to a fear conditioning (FC) procedure followed by a contextual or cued fear memory test (CTX-R and CS-R, respectively). Morphine (MOR, 1 mg/kg/ip) was injected immediately after FC to prevent the fear consolidation process. Real-time quantitative PCR was used to measure the mRNA expression levels of Gα subunits at 1 h after FC, 24 h after FC, and 1 h after the CTX-R or CS-R. In the HP, the mRNA levels of Gα(s), Gα(12) and Gα(11) were higher at 1 h after training. Gα(s) levels were slightly lower when consolidation was stabilized and after the CS-R. The mRNA levels of Gα(12) were increased at 1 h after FC, returned to control levels at 24 h after FC and increased again with the CTX-R. The increase in the Gα(11) level persisted at 24 h after FC and after CTX-R. In the AMY, no specific changes were induced by FC. In the PFC, CTX-R was accompanied by a decrease in Gα(i/o) mRNA levels; however, only Gα(i2) downregulation was prevented by MOR treatment. Hence, the FC-evoked changes in Gα mRNA expression were observed mainly in the HP and connected primarily to contextual learning. These results suggest that the activation of signaling pathways by Gα(s) and Gα(12) is required to begin the fear memory consolidation process in the HP, while signal transduction via Gα(11) is implicated in the maintenance of fear consolidation. In the PFC, the downregulation of Gα(i2) appears to be related to the contextual learning of fear.
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Affiliation(s)
- Agnieszka Zelek-Molik
- Institute of Pharmacology, Polish Academy of Sciences, Department of Brain Biochemistry, 31-343 Krakow, Smętna Street 12, Poland
| | - Marco Costanzi
- Free University Maria Ss. Assunta (LUMSA), Department of Human Sciences, Rome, Italy
| | - Katarzyna Rafa-Zabłocka
- Institute of Pharmacology, Polish Academy of Sciences, Department of Brain Biochemistry, 31-343 Krakow, Smętna Street 12, Poland
| | - Grzegorz Kreiner
- Institute of Pharmacology, Polish Academy of Sciences, Department of Brain Biochemistry, 31-343 Krakow, Smętna Street 12, Poland
| | - Adam Roman
- Institute of Pharmacology, Polish Academy of Sciences, Department of Brain Biochemistry, 31-343 Krakow, Smętna Street 12, Poland
| | - Jerzy Vetulani
- Institute of Pharmacology, Polish Academy of Sciences, Department of Brain Biochemistry, 31-343 Krakow, Smętna Street 12, Poland
| | | | - Vincenzo Cestari
- Sapienza University Rome, Department of Psychology, Rome, Italy.
| | - Irena Nalepa
- Institute of Pharmacology, Polish Academy of Sciences, Department of Brain Biochemistry, 31-343 Krakow, Smętna Street 12, Poland.
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Zalewska T, Bielawski A, Stanaszek L, Wieczerzak K, Ziemka-Nałęcz M, Nalepa I. Imipramine administration induces changes in the phosphorylation of FAK and PYK2 and modulates signaling pathways related to their activity. Biochim Biophys Acta Gen Subj 2015; 1860:424-33. [PMID: 26620976 DOI: 10.1016/j.bbagen.2015.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/26/2015] [Accepted: 11/22/2015] [Indexed: 02/05/2023]
Abstract
BACKGROUND Antidepressants can modify neuronal functioning by affecting many levels of signal transduction pathways that are involved in neuroplasticity. We investigated whether the phosphorylation status of focal adhesion kinase (FAK/PTK2) and its homolog, PYK2/PTK2B, and their complex with the downstream effectors (Src kinase, p130Cas, and paxillin) are affected by administration of the antidepressant drug, imipramine. The treatment influence on the levels of ERK1/2 kinases and their phosphorylated forms (pERK1/2) or the Gαq, Gα11 and Gα12 proteins were also assessed. METHODS Rats were injected with imipramine (10 mg/kg, twice daily) for 21 days. The levels of proteins investigated in their prefrontal cortices were measured by Western blotting. RESULTS Imipramine induced contrasting changes in the phosphorylation of FAK and PYK2 at Tyr397 and Tyr402, respectively. The decreased FAK phosphorylation and increased PYK2 phosphorylation were reflected by changes in the levels of their complex with Src and p130Cas, which was observed predominantly after chronic imipramine treatment. Similarly only chronic imipramine decreased the Gαq expression while Gα11 and Gα12 proteins were untouched. Acute and chronic treatment with imipramine elevated ERK1 and ERK2 total protein levels, whereas only the pERK1 was significantly affected by the drug. CONCLUSION The enhanced activation of PYK2 observed here could function as compensation for FAK inhibition. GENERAL SIGNIFICANCE These data demonstrate that treatment with imipramine, which is a routine in counteracting depressive disorders, enhances the phosphorylation of PYK2, a non-receptor kinase instrumental in promoting synaptic plasticity. This effect documents as yet not considered target in the mechanism of imipramine action.
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Affiliation(s)
- Teresa Zalewska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Adam Bielawski
- Department of Brain Biochemistry, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Luiza Stanaszek
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Krzysztof Wieczerzak
- Department of Brain Biochemistry, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Małgorzata Ziemka-Nałęcz
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Irena Nalepa
- Department of Brain Biochemistry, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland.
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Di Prisco S, Merega E, Lanfranco M, Casazza S, Uccelli A, Pittaluga A. Acute desipramine restores presynaptic cortical defects in murine experimental autoimmune encephalomyelitis by suppressing central CCL5 overproduction. Br J Pharmacol 2014; 171:2457-67. [PMID: 24528439 DOI: 10.1111/bph.12631] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/14/2014] [Accepted: 02/05/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Altered glutamate exocytosis and cAMP production in cortical terminals of experimental autoimmune encephalomyelitis (EAE) mice occur at the early stage of disease (13 days post-immunization, d.p.i.). Neuronal defects were paralleled by overexpression of the central chemokine CCL5 (also known as RANTES), suggesting it has a role in presynaptic impairments. We propose that drugs able to restore CCL5 content to physiological levels could also restore presynaptic defects. Because of its efficacy in controlling CCL5 overexpression, desipramine (DMI) appeared to be a suitable candidate to test our hypothesis. EXPERIMENTAL APPROACH Control and EAE mice at 13 d.p.i. were acutely or chronically administered DMI and monitored for behaviour and clinical scores. Noradrenaline and glutamate release, cAMP, CCL5 and TNF-α production were quantified in cortical synaptosomes and homogenates. Peripheral cytokine production was also determined. KEY RESULTS Noradrenaline exocytosis and α₂ -adrenoeceptor-mediated activity were unmodified in EAE mice at 13 d.p.i. when compared with control. Acute, but not chronic, DMI reduced CCL5 levels in cortical homogenates of EAE mice at 13 d.p.i., but did not affect peripheral IL-17 and TNF-α contents or CCL5 plasma levels. Acute DMI caused a long-lasting restoration of glutamate exocytosis, restored endogenous cAMP production and impeded the shift from inhibition to facilitation of the CCL5-mediated control of glutamate exocytosis. Finally, DMI ameliorated anxiety-related behaviour but not motor activity or severity of clinical signs. CONCLUSIONS We propose DMI as an add-on therapy to normalize neuropsychiatric symptoms in multiple sclerosis patients at the early stage of the disease.
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Affiliation(s)
- Silvia Di Prisco
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Genoa, Italy
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Ciraulo DA, Barlow DH, Gulliver SB, Farchione T, Morissette SB, Kamholz BW, Eisenmenger K, Brown B, Devine E, Brown TA, Knapp CM. The effects of venlafaxine and cognitive behavioral therapy alone and combined in the treatment of co-morbid alcohol use-anxiety disorders. Behav Res Ther 2013; 51:729-35. [PMID: 24055681 PMCID: PMC3981550 DOI: 10.1016/j.brat.2013.08.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/06/2013] [Accepted: 08/19/2013] [Indexed: 01/01/2023]
Abstract
The effects of the antidepressant venlafaxine (VEN-225 mg daily) and transdiagnostic cognitive behavioral treatment (CBT) alone and in combination on alcohol intake in subjects with co-morbid alcohol use disorders (AUDs) and anxiety disorders were compared. Drinking outcomes and anxiety were assessed for 81 subjects treated for 11 weeks with one of 4 conditions: 1) VEN-CBT, 2) VEN-Progressive Muscle Relaxation therapy (PMR), 3) Placebo (PLC)-CBT and 4) a comparison group of PLC-PMR. For subjects who reported taking at least one dose of study medication, the Time×Group interaction was significant for percent days of heavy drinking and drinks consumed per day. For the measure of percent days heavy drinking, the paired comparison of PLC-CBT versus PLC-PMR group indicated that the PLC-CBT group had greater drinking reductions, whereas other groups were not superior to the comparison group. In Week 11, the proportion of subjects in the PLC-CBT group that had a 50% reduction from baseline in percent days heavy drinking was significantly greater than those in the comparison group. Of the 3 "active treatment" groups only the PLC-CBT group had significantly decreased heavy drinking when contrasted to the comparison group. This finding suggests that the transdiagnostic CBT approach of Barlow and colleagues may have value in the management of heavy drinking in individuals with co-morbid alcoholism and anxiety.
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Affiliation(s)
- Domenic A Ciraulo
- Department of Psychiatry, Boston University School of Medicine, Boston, MA, United States.
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Sadakierska-Chudy A, Haduch A, Rysz M, Gołembiowska K, Daniel WA. The role of brain noradrenergic system in the regulation of liver cytochrome P450 expression. Biochem Pharmacol 2013; 86:800-7. [DOI: 10.1016/j.bcp.2013.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/12/2013] [Accepted: 07/15/2013] [Indexed: 12/19/2022]
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Hood SD, Melichar JK, Taylor LG, Kalk N, Edwards TR, Hince DA, Lenox-Smith A, Lingford-Hughes AR, Nutt DJ. Noradrenergic function in generalized anxiety disorder: impact of treatment with venlafaxine on the physiological and psychological responses to clonidine challenge. J Psychopharmacol 2011; 25:78-86. [PMID: 20093317 DOI: 10.1177/0269881109359099] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Serotonin and noradrenaline reuptake inhibitor (SNRI) antidepressants have evidence of efficacy in the treatment of generalized anxiety disorder (GAD); however, it is not clear whether there is an advantage over selective serotonin reuptake inhibitor (SSRI) medicines and there is limited evidence for noradrenergic dysfunction in GAD. We tested whether a dysfunctional alpha-2 adrenoceptor system is present in patients with GAD and the effects of SNRI treatment on this system. The method used was an infusion of clonidine (a selective alpha-2 adrenergic receptor agonist) on psychological and physiological outcomes in three subject groups: 10 untreated GAD patients, five SNRI-treated GAD patients and seven normal controls. The clonidine challenge elicited sedation, a rise in growth hormone, decrease in blood pressure, decline in saccadic eye movement (SEM) variables, and improvement in verbal fluency as anticipated in the 22 subjects examined. Lower cortisol levels were found in controls and higher blood pressure readings in GAD-treated subjects, as well as evidence that GAD-treated subjects had SEMs that were intermediate between control and GAD subjects' scores and have less clonidine-induced sedation. The implications of these findings with reference to the study hypothesis in this small study are discussed.
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Affiliation(s)
- S D Hood
- Psychopharmacology Unit, University of Bristol, Bristol, UK.
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Simbrey K, Winterhoff H, Butterweck V. Extracts of St. John's wort and various constituents affect beta-adrenergic binding in rat frontal cortex. Life Sci 2004; 74:1027-38. [PMID: 14672758 DOI: 10.1016/j.lfs.2003.07.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study was designed to get further insight into the mode of antidepressant action of extracts prepared from St. John's wort (SJW) and relevant active constituents. Down-regulation of central beta-adrenergic receptors (beta-AR's) has been widely considered a common biochemical marker of antidepressant efficacy. Although previous studies have reported a beta-AR down-regulation for SJW extracts, in vivo studies that compare the effects of SJW extracts with those of relevant active constituents on beta-AR density have not been done yet. We used quantitative radioligand receptor-binding-studies to examine in rats the effects of short-term (2 wks) and long-term (8 wks) administration of different SJW extracts and constituents on beta-AR binding in rat frontal cortex. The effects were compared to those of the standard antidepressants imipramine and fluoxetine. [125I]CYP binding to beta-AR was found to be decreased after short as well as after long-term treatment with imipramine (36%, 40%). Short-term treatment with fluoxetine decreased the number of beta-adrenergic receptors (17%) while long-term treatment with fluoxetine elicited an increase (14%) in beta-AR-binding. This effect was comparable to that of the lipophilic CO2 extract which decreased beta-AR-binding (13%) after two weeks and slightly increased the number of beta-AR's after 8 weeks (9%). Short-term treatment with the methanolic SJW extract decreased beta-AR-binding (14%), no effects for this extract were observed after 8 weeks. Treatment with hypericin led to a significant down-regulation (13%) of beta-AR's in the frontal cortex after 8-weeks, but not after 2 weeks, while hyperforin (used as trimethoxybenzoate, TMB), and hyperoside were ineffective in both treatment paradigms. Compared to the SJW extracts and single compounds the effect of imipramine on beta-AR-binding was more pronounced in both treatment paradigms.
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Affiliation(s)
- K Simbrey
- Institute of Pharmacology and Toxicology, Universitätsklinikum Münster, Domagkstrasse 12, 48149 Münster, Germany
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Butterweck V, Simbrey K, Seo S, Sasaki T, Nishibe S. Long-term effects of an Apocynum venetum extract on brain monoamine levels and beta-AR density in rats. Pharmacol Biochem Behav 2003; 75:557-64. [PMID: 12895673 DOI: 10.1016/s0091-3057(03)00118-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The present study was designed to get further insight into the mode of antidepressant action of an extract prepared of the leaves of Apocynum venetum L. (AV). To evaluate biochemical changes, we used a high-performance liquid chromatography system to examine the effects of short-term (2 weeks) and long-term (8 weeks) administration of imipramine (15 mg/kg po) and an AV-extract (15, 60 and 250 mg/kg) on regional levels of serotonin (5-HT), norepinephrine (NE), dopamine (DA) and their metabolites in the rat hypothalamus, striatum and hippocampus. Pronounced changes in 5-HT, NE and DA levels were detected mainly after 8 weeks of daily imipramine treatment. Similar to imipramine, AV-extract reduced NE and DA concentrations after 8 weeks, whereas it failed to affect 5-HT levels. We speculate that the decrease in NE levels after chronic AV treatment might be based partly on the subsensitivity of presynaptic alpha(2)-receptors. In addition to the determination of central monoamine concentrations, quantitative radioligand receptor-binding studies were used to examine the effects of long-term administration of imipramine and AV-extract on beta-adrenergic binding in rat frontal cortex. [125I]CYP binding to beta-adrenergic receptors was found to be decreased after 8 weeks treatment with imipramine, whereas AV-extract had no effect on beta-receptor binding.
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Affiliation(s)
- Veronika Butterweck
- Institute of Pharmacology and Toxicology, Universitätsklinikum Muenster, Domagkstrasse 12, 48149 Münster, Germany.
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Abstract
Depression is a serious and burdensome illness. Although selective serotonin reuptake inhibitors (SSRIs) have improved safety and tolerability of antidepressant treatment efficacy, the delay in the onset of action have not been improved. There is evidence to suggest that the delay in onset of therapeutic activity is a function of the drugs, rather than the disease. This suggests that research into the biological characteristics of depression and its treatments may yield faster-acting antidepressants. Emerging evidence from clinical studies with mirtazapine, venlafaxine and SSRI augmentation with pindolol suggests that these treatments may relieve antidepressant symptoms more rapidly than SSRIs. The putative mechanism of action of faster-acting antidepressant strategies presented here purports that conventional antidepressants acutely increase the availability of serotonin (5-hydroxytryptamine, 5-HT) or noradrenaline (NA), preferentially at their cell body level, which triggers negative feedback mechanisms. After continued stimulation, these feedback mechanisms become desensitised and the enhanced 5-HT availability is able to enhance 5-HT and/or NA neurotransmission. Putative fast-onset antidepressants, on the other hand, may uncouple such feedback control mechanisms and enhance 5-HT and/or NA neurotransmission more rapidly. Further studies are required to characterise in detail the interactions between NA and 5-HT systems and to definitively establish the early onset of candidate antidepressants such as mirtazapine, venlafaxine and pindolol augmentation.
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Affiliation(s)
- Pierre Blier
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Room L4-100, PO Box 100256, Gainesville, FL 32610-0383, USA.
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Abstract
Venlafaxine (Effexor) is an effective antidepressant and has also been approved for the treatment of generalized anxiety disorder. Venlafaxine was initially characterized as an inhibitor of both serotonin (5HT) and norepinephrine (NE) uptake and was therefore termed a "dual uptake inhibitor." This chapter reviews data from both in vitro and in vivo studies regarding its effects on 5HT and NE neurotransmission. In addition, the effects of venlafaxine on other systems that may play a role in its therapeutic efficacy effects are described. The data indicate that venlafaxine is a relatively weak inhibitor of NE transport in vitro. In vivo studies indicate that venlafaxine selectively inhibits 5HT uptake at low therapeutic doses and inhibits both 5HT and NE uptake at higher therapeutic doses. This chapter concludes with a discussion of the effects of venlafaxine on various aspects of physiology.
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Affiliation(s)
- P H Roseboom
- Department of Psychiatry, University of Wisconsin-Madison 53719-1176, USA
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Manier DH, Shelton RC, Sulser F. Cross-talk between PKA and PKC in human fibroblasts: what are the pharmacotherapeutic implications? J Affect Disord 2001; 65:275-9. [PMID: 11511407 DOI: 10.1016/s0165-0327(00)00278-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND The present study was designed to confirm or refute in human fibroblasts the hypothesized cross-talk elicited via neurotransmitter transduction cascades at the level of protein kinase mediated phosphorylation of the nuclear transcription factor CREB. METHODS Human fibroblasts from normal control subjects were subcultured and incubated at confluency after five growth passages with isoproterenol (stimulation of PKA mediated phosphorylation) and/or phorbol 12-myristate 13-acetate (PMA) (stimulation of PKC mediated phosphorylation) followed by the determination of nuclear CREB-P by immunoblotting, enhanced chemiluminescence and quantitation of the autoradiograms by laser densitometry. RESULTS Using the nuclear transcription factor CREB as a target, both the activation of the cyclic AMP-PKA pathway by isoproterenol and the activation of the PKC pathway by PMA caused phosphorylation of nuclear CREB. This phosphorylation is additive in nature and appears to occur at the same molecular site, serine133 of CREB. CONCLUSIONS The present results in human fibroblasts demonstrate that the hypothesized cross-talk at the level of protein kinase mediated phosphorylation of transcription factors is no longer hypothetical. Since it is the phosphorylation of nuclear CREB that determines its dimerization and transcriptional activation of programs of CRE containing genes, the results suggest that this convergence of the neurotransmitter signals may be the critical mechanism in gene expression following the administration of antidepressant drugs that affect noradrenergic, serotonergic or both transduction cascades. The results may also provide a rationale for the apparent superior clinical efficacy of dual uptake inhibitors.
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Affiliation(s)
- D H Manier
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, TN 37232-2647, USA
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Abstract
As a testable heuristic, the concept of stress response and adaptation is highly appealing, and the support for the concept is strong. This explanatory model of depression may account for hitherto apparently discordant facts--contradictory symptoms, antidepressant drugs that act on differing systems, facilitation of antidepressant response by augmentation, and response to psychotherapy and pharmacotherapy. This article has focused narrowly on specific cellular elements of the stress-adaptational mechanisms, including the AC-PKA and PLC-PKC transductional cascades, together with specific response elements, such as the HPA axis, BDNF, and NMDA receptors; however, other important mechanisms, including specific receptor subtypes (e.g., 5-HT1A and NE alpha 2), transmitter systems (e.g., acetylcholine and depamine), and hormones (e.g., thyroid and growth hormones and prolactin), which may be important, have not been discussed. As the complex interactions of these systems gradually yield to investigation, not only will new treatments be developed, but better matching of treatment to patient may become an achievable goal.
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Affiliation(s)
- R C Shelton
- Departments of Psychiatry and Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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Abstract
Since the discovery of first antidepressants in mid-1950's, the field has been intensively studied. Several new classes of compounds emerged and several hypotheses on the mechanism of their action were proposed. The novel antidepressants are either selective and reversible monoamine oxidase inhibitors, (e.g., moclobemide), or selective serotonin reuptake inhibitors (e.g., citalopram or paroxetine), or serotonin and noradrenaline reuptake inhibitors (e.g. , venlafaxine). Recently neuropeptides (e.g., thyrotropin-releasing hormone,TRH) or antagonists of neuropeptide receptors (e.g., tachykinin NK(1) receptor) undergo clinical tests. Several hypotheses proposed the predominant involvement of one or few neurotransmitter receptors in the mechanism of antidepressant action, but it is now assumed that several distinct receptor mechanisms' trigger different but converging intracellular signal cascades that activate transcription factors, which, in turn, promote the expression of genes encoding for proteins, that play a crucial role in restoring of neuronal functions involved in mood regulation.
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Affiliation(s)
- J Vetulani
- Institute of Pharmacology PAN, Polish Academy of Sciences, Smetna 12, 31-343, Cracow, Poland.
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Seo DO, Shin CY, Lee CJ, Dailey JW, Reith ME, Jobe PC, Ko KH. Effect of alterations in extracellular norepinephrine on adrenoceptors: a microdialysis study in freely moving rats. Eur J Pharmacol 1999; 365:39-46. [PMID: 9988121 DOI: 10.1016/s0014-2999(98)00856-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chronic electroshock treatment (once daily for 12 days) increases extracellular norepinephrine in the frontal cortex and hippocampus as measured by microdialysis. This chronic treatment produced an elevation of basal norepinephrine overflow into extracellular space while both the first and the twelfth treatments produced a transient increase in norepinephrine overflow of about 40 min. Acutely, desmethylimipramine (10 mg/kg) treatment significantly increased extracellular norepinephrine. While chronic desmethylimipramine (once daily for 10 days) increased basal overflow of norepinephrine in the frontal cortex and hippocampus, the tenth daily administration of desmethylimipramine did not produce a statistically significant increase in extracellular norepinephrine. Both daily electroshock and daily desmethylimipramine produced down regulation of beta-adrenoceptors in the hippocampus and the frontal cortex. Chronic electroshock caused up regulation of alpha-adrenoceptors in the frontal cortex but not in the hippocampus while chronic desmethylimipramine administration did not alter alpha-adrenoceptors in either structure. Depletion of norepinephrine with reserpine or with 6-hydroxydopamine prevented the down regulation of beta-adrenoceptors while depletion of this neurotransmitter did not prevent the electroshock-induced up regulation of alpha-adrenoceptors in the frontal cortex. These data suggest that down regulation of beta-adrenoceptors is mediated through increases in extracellular norepinephrine. In contrast, up regulation of alpha-adrenoceptors appears to be independent of norepinephrine release and does not require the presence of noradrenergic neurons in order to be induced by electroshock.
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MESH Headings
- Adrenergic Uptake Inhibitors/pharmacology
- Animals
- Desipramine/pharmacology
- Down-Regulation
- Electroshock
- Extracellular Space/drug effects
- Extracellular Space/metabolism
- Frontal Lobe/drug effects
- Frontal Lobe/metabolism
- Hippocampus/drug effects
- Hippocampus/metabolism
- Male
- Microdialysis
- Norepinephrine/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic/drug effects
- Receptors, Adrenergic/metabolism
- Receptors, Adrenergic, alpha/drug effects
- Receptors, Adrenergic, alpha/metabolism
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Up-Regulation
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Affiliation(s)
- D O Seo
- Department of Pharmacology, College of Pharmacy, Seoul National University, South Korea
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