151
|
Kulkarni VA, Jha S, Vaidya VA. Depletion of norepinephrine decreases the proliferation, but does not influence the survival and differentiation, of granule cell progenitors in the adult rat hippocampus. Eur J Neurosci 2002; 16:2008-12. [PMID: 12453065 DOI: 10.1046/j.1460-9568.2002.02268.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The dentate gyrus region retains the ability to generate neurons throughout adulthood. A few studies have examined the neurotransmitter regulation of adult hippocampal neurogenesis and have shown that this process is regulated by serotonin and glutamate. Given the strong noradrenergic innervation of the adult hippocampus and the ability of norepinephrine to influence proliferation during development, we examined the influence of norepinephrine on adult hippocampal neurogenesis. Our study indicates that depletion of norepinephrine by the selective noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromo benzylamine hydrochloride (DSP-4), results in a 63% reduction in the proliferation of dentate gyrus progenitor cells identified through 5-bromo-2'-deoxyuridine (BrdU) labelling. In contrast, the survival of BrdU-positive cells labelled prior to treatment with DSP-4 is not influenced by norepinephrine depletion. The differentiation of BrdU labelled progenitors into neurons or glia was also not sensitive to noradrenergic depletion. These results indicate that the proliferation, but not the survival or differentiation, of adult hippocampal granule cell progenitors is affected by norepinephrine depletion.
Collapse
Affiliation(s)
- Vaishali A Kulkarni
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | | | | |
Collapse
|
152
|
Goergen EM, Bagay LA, Rehm K, Benton JL, Beltz BS. Circadian control of neurogenesis. JOURNAL OF NEUROBIOLOGY 2002; 53:90-5. [PMID: 12360586 DOI: 10.1002/neu.10095] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The life-long addition of new neurons has been documented in many regions of the vertebrate and invertebrate brain, including the hippocampus of mammals (Altman and Das, 1965; Eriksson et al., 1998; Jacobs et al., 2000), song control nuclei of birds (Alvarez-Buylla et al., 1990), and olfactory pathway of rodents (Lois and Alvarez-Buylla, 1994), insects (Cayre et al., 1996) and crustaceans (Harzsch and Dawirs, 1996; Sandeman et al., 1998; Harzsch et al., 1999; Schmidt, 2001). The possibility of persistent neurogenesis in the neocortex of primates is also being widely discussed (Gould et al., 1999; Kornack and Rakic, 2001). In these systems, an effort is underway to understand the regulatory mechanisms that control the timing and rate of neurogenesis. Hormonal cycles (Rasika et al., 1994; Harrison et al., 2001), serotonin (Gould, 1999; Brezun and Daszuta, 2000; Beltz et al., 2001), physical activity (Van Praag et al., 1999) and living conditions (Kemperman and Gage, 1999; Sandeman and Sandeman, 2000) influence the rate of neuronal proliferation and survival in a variety of organisms, suggesting that mechanisms controlling life-long neurogenesis are conserved across a range of vertebrate and invertebrate species. The present article extends these findings by demonstrating circadian control of neurogenesis. Data show a diurnal rhythm of neurogenesis among the olfactory projection neurons in the crustacean brain, with peak proliferation during the hours surrounding dusk, the most active period for lobsters. These data raise the possibility that light-controlled rhythms are a primary regulator of neuronal proliferation, and that previously-demonstrated hormonal and activity-driven influences over neurogenesis may be secondary events in a complex circadian control pathway.
Collapse
Affiliation(s)
- Erin M Goergen
- Department of Biological Sciences, Wellesley College, Wellesley, Massacusetts 02481, USA
| | | | | | | | | |
Collapse
|
153
|
Kempermann G. Neuronal stem cells and adult neurogenesis. ERNST SCHERING RESEARCH FOUNDATION WORKSHOP 2002:17-28. [PMID: 11816271 DOI: 10.1007/978-3-662-04816-0_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- G Kempermann
- Max Delbrück Centrum für Molekulare Medizin, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| |
Collapse
|
154
|
|
155
|
Cayre M, Malaterre J, Scotto-Lomassese S, Strambi C, Strambi A. The common properties of neurogenesis in the adult brain: from invertebrates to vertebrates. Comp Biochem Physiol B Biochem Mol Biol 2002; 132:1-15. [PMID: 11997205 DOI: 10.1016/s1096-4959(01)00525-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Until recently, it was believed that adult brains were unable to generate any new neurons. However, it is now commonly known that stem cells remain in the adult central nervous system and that adult vertebrates as well as adult invertebrates are currently adding new neurons in some specialized structures of their central nervous system. In vertebrates, the subventricular zone and the dentate gyrus of the hippocampus are the sites of neuronal precursor proliferation. In some insects, persistent neurogenesis occurs in the mushroom bodies, which are brain structures involved in learning and memory and considered as functional analogues of the hippocampus. In both vertebrates and invertebrates, secondary neurogenesis (including neuroblast proliferation and neuron differentiation) appears to be regulated by hormones, transmitters, growth factors and environmental cues. The functional implications of adult neurogenesis have not yet been clearly demonstrated and comparative study of the various model systems could contribute to better understand this phenomenon. Here, we review and discuss the common characteristics of adult neurogenesis in the various animal models studied so far.
Collapse
Affiliation(s)
- Myriam Cayre
- CNRS, Laboratoire de Neurobiologie, Marseille, France.
| | | | | | | | | |
Collapse
|
156
|
Abstract
Major depression, whose biological origins have been difficult to grasp for decades, might result from a disturbance in neuronal plasticity. New theories begin to consider a fundamental role of adult hippocampal neurogenesis in this loss of plasticity. Could depression and other mood disorders therefore be 'stem cell disorders'? In this review, the potential role of adult hippocampal neurogenesis and of neuronal stem or progenitor cells in depression is discussed with regard to those aspects that are brought up by recent research on how adult hippocampal neurogenesis is regulated. What is known about this regulation today are mosaic pieces and indicates that regulation is complex and is modulated on several levels. Accordingly, emphasis is here laid on those regulatory feedback mechanisms and interdependencies that could help to explain how the pathogenic progression from a hypothesized disruptive cause can occur and lead to the complex clinical picture in mood disorders. While the 'neurogenic theory' of depression remains highly speculative today, it might stimulate the generation of sophisticated working hypotheses, useful animal experiments and the first step towards new therapeutic approaches.
Collapse
Affiliation(s)
- Gerd Kempermann
- Max-Delbrück-Center for Molecular Medicine (MDC), Berlin-Buch, and Department of Neurology, Charité University Hospital, Humboldt University Berlin, Berlin, Germany.
| |
Collapse
|
157
|
Azmitia EC. Modern views on an ancient chemical: serotonin effects on cell proliferation, maturation, and apoptosis. Brain Res Bull 2001; 56:413-24. [PMID: 11750787 DOI: 10.1016/s0361-9230(01)00614-1] [Citation(s) in RCA: 374] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Evolutionarily, serotonin existed in plants even before the appearance of animals. Indeed, serotonin may be tied to the evolution of life itself, particularly through the role of tryptophan, its precursor molecule. Tryptophan is an indole-based, essential amino acid which is unique in its light-absorbing properties. In plants, tryptophan-based compounds capture light energy for use in metabolism of glucose and the generation of oxygen and reduced cofactors. Tryptophan, oxygen, and reduced cofactors combine to form serotonin. Serotonin-like molecules direct the growth of light-capturing structures towards the source of light. This morphogenic property also occurs in animal cells, in which serotonin alters the cytoskeleton of cells and thus influences the formation of contacts. In addition, serotonin regulates cell proliferation, migration and maturation in a variety of cell types, including lung, kidney, endothelial cells, mast cells, neurons and astrocytes). In brain, serotonin has interactions with seven families of receptors, numbering at least 14 distinct proteins. Of these, two receptors are important for the purposes of this review. These are the 5-HT1A and 5-HT2A receptors, which in fact have opposing functions in a variety of cellular and behavioral processes. The 5-HT1A receptor develops early in the CNS and is associated with secretion of S-100beta from astrocytes and reduction of c-AMP levels in neurons. These actions provide intracellular stability for the cytoskeleton and result in cell differentiation and cessation of proliferation. Clinically, 5-HT1A receptor drugs decrease brain activity and act as anxiolytics. The 5-HT2A receptor develops more slowly and is associated with glycogenolysis in astrocytes and increased Ca(++) availability in neurons. These actions destabilize the internal cytoskeleton and result in cell proliferation, synaptogenesis, and apoptosis. In humans, 5-HT2A receptor drugs produce hallucinations. The dynamic interactions between the 5-HT1A and 5-HT2A receptors and the cytoskeleton may provide important insights into the etiology of brain disorders and provide novel strategies for their treatment.
Collapse
Affiliation(s)
- E C Azmitia
- Department of Biology, Center for Neural Science, New York University, New York, NY, USA.
| |
Collapse
|
158
|
Banasr M, Hery M, Brezun JM, Daszuta A. Serotonin mediates oestrogen stimulation of cell proliferation in the adult dentate gyrus. Eur J Neurosci 2001; 14:1417-24. [PMID: 11722603 DOI: 10.1046/j.0953-816x.2001.01763.x] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Characterizing the mechanisms by which endogenous factors stimulate neurogenesis is of special interest in view of the possible implication of newly generated cells in hippocampal functions or disorders. The aim of this study was to determine whether serotonin (5-HT) and oestradiol (E2) act through a common pathway to increase cell proliferation in the adult dentate gyrus (DG). We also investigated the effects of long-lasting changes in oestrogen levels on cell proliferation. Combining ovariectomy with inhibition of 5-HT synthesis using p-chlorophenylalanine (PCPA) treatment produced approximately the same decreases in the number of bromodeoxyuridine (BrdU) and PSA-NCAM immunolabelled cells in the subgranular layer as ovariectomy alone. Administration of 5-hydroxytryptophan (5-HTP) restored cell proliferation primarily decreased by ovariectomy, whereas oestradiol was unable to reverse this change in ovariectomized rats treated with PCPA. These findings demonstrate that 5-HT mediates oestrogen stimulation of cell proliferation in adult dentate gyrus. However, increase in ovarian hormones during pregnancy has no effect on dentate cell proliferation. This finding suggests that concomitant changes in other factors, such as glucocorticoids, may counterbalance the positive regulation of cell proliferation by 5-HT and oestradiol. Finally, oestrogen may regulate structural plasticity by stimulating PSA-NCAM expression independently of neurogenesis, as shown for instance by the increases in the number of PSA-NCAM labelled cells in pregnants. As 5-HT and oestrogen are involved in mood disorders, our data suggest that the positive regulation of cell proliferation and neuroplasticity by these two factors may contribute to restore hippocampal connectivity in depressive patients.
Collapse
Affiliation(s)
- M Banasr
- Laboratoire de Neurobiologie Cellulaire et Fonctionnelle, CNRS, 31 Chemin J. Aiguier 13402 Marseille cedex 20, France
| | | | | | | |
Collapse
|
159
|
Czéh B, Michaelis T, Watanabe T, Frahm J, de Biurrun G, van Kampen M, Bartolomucci A, Fuchs E. Stress-induced changes in cerebral metabolites, hippocampal volume, and cell proliferation are prevented by antidepressant treatment with tianeptine. Proc Natl Acad Sci U S A 2001; 98:12796-801. [PMID: 11675510 PMCID: PMC60133 DOI: 10.1073/pnas.211427898] [Citation(s) in RCA: 786] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2001] [Accepted: 08/14/2001] [Indexed: 12/22/2022] Open
Abstract
Stress-induced structural remodeling in the adult hippocampus, involving debranching and shortening of dendrites and suppression of neurogenesis, provides a cellular basis for understanding the impairment of neural plasticity in the human hippocampus in depressive illness. Accordingly, reversal of structural remodeling may be a desirable goal for antidepressant therapy. The present study investigated the effect of tianeptine, a modified tricyclic antidepressant, in the chronic psychosocial stress model of adult male tree shrews (Tupaia belangeri), a model with high validity for research on the pathophysiology of major depression. Animals were subjected to a 7-day period of psychosocial stress to elicit stress-induced endocrine and central nervous alterations before the onset of daily oral administration of tianeptine (50 mg/kg). The psychosocial stress continued throughout the treatment period of 28 days. Brain metabolite concentrations were determined in vivo by proton magnetic resonance spectroscopy, cell proliferation in the dentate gyrus was quantified by using BrdUrd immunohistochemistry, and hippocampal volume was measured post mortem. Chronic psychosocial stress significantly decreased in vivo concentrations of N-acetyl-aspartate (-13%), creatine and phosphocreatine (-15%), and choline-containing compounds (-13%). The proliferation rate of the granule precursor cells in the dentate gyrus was reduced (-33%). These stress effects were prevented by the simultaneous administration of tianeptine yielding normal values. In stressed animals treated with tianeptine, hippocampal volume increased above the small decrease produced by stress alone. These findings provide a cellular and neurochemical basis for evaluating antidepressant treatments with regard to possible reversal of structural changes in brain that have been reported in depressive disorders.
Collapse
Affiliation(s)
- B Czéh
- Division of Neurobiology, German Primate Center, 37077 Göttingen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
160
|
Affiliation(s)
- R M Sapolsky
- Department of Biological Sciences, Stanford University, Stanford University School of Medicine, Gilbert Laboratory, MC 5020, Stanford, CA 94305-5020, USA.
| |
Collapse
|
161
|
Ormerod BK, Galea LA. Reproductive status influences cell proliferation and cell survival in the dentate gyrus of adult female meadow voles: a possible regulatory role for estradiol. Neuroscience 2001; 102:369-79. [PMID: 11166123 DOI: 10.1016/s0306-4522(00)00474-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Galea and McEwen [Galea and McEwan (1999) Neuroscience 89, 955-964] found that cell proliferation was suppressed in female meadow voles trapped during the breeding season relative to females trapped during the non-breeding season. We investigated the effect of reproductive status and estradiol level on cell proliferation and cell survival in adult laboratory-reared female meadow voles to control for the variables of age, experience and pregnancy that could confound the results derived from a wild sample. Voles were housed in either a long- or short-photoperiod to simulate season and a male or female cage partner was introduced to influence reproductive status. Because females are reflex ovulators, exposure to a male rapidly induces behavioural estrous and high levels of estradiol. Forty-eight hours after introducing a cage partner, we injected either bromodeoxyuridine or [3H]thymidine to mark cell synthesis and then examined labelled cells 2h (cell proliferation) or five weeks (cell survival) later, respectively. To determine whether estradiol mimicked the effect of reproductive status, groups of reproductively inactive females were given a single injection of estradiol benzoate (10 microg) either four or 48h prior to bromodeoxyuridine labelling. The density of proliferating cells in the granule cell layer and the hilus was elevated in reproductively inactive females compared to reproductively active females and was correlated negatively with serum estradiol level. Exposure to estradiol benzoate initially increased cell proliferation (within 4h) but subsequently suppressed cell proliferation (within 48h). In addition, the density of surviving cells was greater in reproductively inactive females relative to reproductively active females but reproductively active females had a greater rate of cell survival than did reproductively inactive females. Reproductive status did not influence the number of pyknotic cells in the dentate gyrus (at either 2h or five weeks).We conclude that reproductive status regulates cell proliferation in adult female meadow voles, possibly via an estradiol-regulated mechanism. The results from the present study showed that reproductively active female meadow voles have suppressed rates of cell proliferation in the dentate gyrus relative compared with reproductively inactive female meadow voles. Administering estradiol initially (within 4h) elevates the cell proliferation within the dentate gyrus of adult females but subsequently (within 48h) suppresses cell proliferation. However, more new cells survived in females with high endogenous levels of estradiol (reproductively active females). In conclusion, reproductive status regulates the level of cell proliferation and survival through a complex estradiol regulated mechanism(s).
Collapse
Affiliation(s)
- B K Ormerod
- Department of Psychology and Graduate Neuroscience Program, The University of British Columbia, BC, V6T 1Z4, Vancouver, Canada.
| | | |
Collapse
|
162
|
Pan Y, Gembom E, Peng W, Lesch KP, Mossner R, Simantov R. Plasticity in serotonin uptake in primary neuronal cultures of serotonin transporter knockout mice. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2001; 126:125-9. [PMID: 11172895 DOI: 10.1016/s0165-3806(00)00145-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The cross talk between dopaminergic and serotonergic systems in the brain has multiple neurophysiological and behavioral implications. Primary neuronal cultures of embryonic wild type (+/+) and serotonin transporter knockout (-/-) mice were used as a model to elucidate the possibility of plasticity at the level of serotonin uptake. Serotonergic neurons were identified in midbrain-hindbrain cultures of both wild type and knockout mice, using polyclonal anti-serotonin antibodies. Adding serotonin (10 microM) to wild type midbrain-hindbrain cultures increased the intensity of serotonin immunostaining, but did not change the number of serotonergic neurons. This increased intensity of serotonin staining was blocked by the serotonin transporter inhibitors fluoxetine and imipramine, but not with the dopamine transporter inhibitor nomifensine. In serotonin transporter knockout cultures, however, serotonin increased both the intensity of serotonin immunostaining and the number of serotonin positive neurons, and nomifensine decreased the number of serotonin-labeled neurons. Uptake of [3H]serotonin to wild type midbrain-hindbrain cultures was completely blocked by 1 microM fluoxetine, whereas nomifensine had a very small effect. In contrast, [3H]serotonin uptake to serotonin transporter knockout cultures, although very weak, was better inhibited by nomifensine than fluoxetine. The results imply that midbrain-hindbrain neuronal cultures of knockout mice, that do not express serotonin transporters, acquire the capacity to take up serotonin, apparently via dopamine transporters.
Collapse
Affiliation(s)
- Y Pan
- Department of Molecular Genetics, Weizmann Institute of Science, 76100, Rehovot, Israel
| | | | | | | | | | | |
Collapse
|
163
|
Abstract
Given the constraints of the prevailing mental health system in the United States, it has become very challenging for psychiatrists to offer psychotherapy services to patients in need of this modality of treatment. In spite of this situation, the profession has made a consistent effort not only to retain this type of psychiatric care but also to train psychiatric residents in this psychiatric intervention technique and its appropriate indications. In this article, the authors highlight a very important aspect of psychotherapy treatment-the termination phase. They review relevant literature on this subject, discuss some of the most common problems faced by psychiatrists, especially psychiatric residents, when addressing the termination phase of psychotherapy, and then present two cases to illustrate these issues.
Collapse
Affiliation(s)
- V Kapoor
- University of Texas Medical School at Houston, USA
| | | | | |
Collapse
|
164
|
Scott BW, Wojtowicz JM, Burnham WM. Neurogenesis in the dentate gyrus of the rat following electroconvulsive shock seizures. Exp Neurol 2000; 165:231-6. [PMID: 10993683 DOI: 10.1006/exnr.2000.7458] [Citation(s) in RCA: 221] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electroconvulsive shock (ECS) seizures provide an animal model of electroconvulsive therapy (ECT) in humans. Recent evidence indicates that repeated ECS seizures can induce long-term structural and functional changes in the brain, similar to those found in other seizure models. We have examined the effects of ECS on neurogenesis in the dentate gyrus of the adult rat using bromodeoxyuridine (BrdU) immunohistochemistry, which identifies newly generated cells. Cells have also been labeled for neuronal nuclear protein (NeuN) to identify neurons. One month following eight ECS seizures, ECS-treated rats had approximately twice as many BrdU-positive cells as sham-treated controls. Eighty-eight percent of newly generated cells colabeled with NeuN in ECS-treated subjects, compared to 83% in sham-treated controls. These data suggest that there is a net increase in neurogenesis within the hippocampal dentate gyrus following ECS treatment. Similar increases have been reported following kindling and kainic acid- or pilocarpine-induced status epilepticus. Increased neurogenesis appears to be a general response to seizure activity and may play a role in the therapeutic effects of ECT.
Collapse
Affiliation(s)
- B W Scott
- Bloorview Epilepsy Research Program, Institute of Medical Science, Toronto, Ontario, M5S 1A8, Canada
| | | | | |
Collapse
|
165
|
Scotto Lomassese S, Strambi C, Strambi A, Charpin P, Augier R, Aouane A, Cayre M. Influence of environmental stimulation on neurogenesis in the adult insect brain. ACTA ACUST UNITED AC 2000. [DOI: 10.1002/1097-4695(20001115)45:3<162::aid-neu4>3.0.co;2-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|