Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effects
Current antidepressants are suboptimal due incomplete understanding of the neurobiology underlying their behavioral effects. However, imaging studies suggest the hippocampus is a key brain region underpinning antidepressant action. There is increasing attention on the functional segregation of the h...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2021-05-01
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| Series: | Neurobiology of Stress |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352289521000394 |
| _version_ | 1823940024376229888 |
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| author | Brunno Rocha Levone Gerard M. Moloney John F. Cryan Olivia F. O'Leary |
| author_facet | Brunno Rocha Levone Gerard M. Moloney John F. Cryan Olivia F. O'Leary |
| author_sort | Brunno Rocha Levone |
| collection | DOAJ |
| description | Current antidepressants are suboptimal due incomplete understanding of the neurobiology underlying their behavioral effects. However, imaging studies suggest the hippocampus is a key brain region underpinning antidepressant action. There is increasing attention on the functional segregation of the hippocampus into a dorsal region (dHi) predominantly involved in spatial learning and memory, and a ventral region (vHi) which regulates anxiety, a symptom often co-morbid with depression. However, little is known about the roles of these hippocampal sub-regions in the antidepressant response. Moreover, the area between them, the intermediate hippocampus (iHi), has received little attention. Here, we investigated the impact of dHi, iHi or vHi lesions on anxiety- and depressive-like behaviors under baseline or antidepressant treatment conditions in male C57BL/6 mice (n = 8–10). We found that in the absence of fluoxetine, vHi lesions reduced anxiety-like behavior, while none of the lesions affected other antidepressant-sensitive behaviors. vHi lesions prevented the acute antidepressant-like behavioral effects of fluoxetine in the tail suspension test and its anxiolytic effects in the novelty-induced hypophagia test. Intriguingly, only iHi lesions prevented the antidepressant effects of chronic fluoxetine treatment in the forced swim test. dHi lesions did not impact any behaviors either in the absence or presence of fluoxetine. In summary, we found that vHi plays a key role in anxiety-like behavior and its modulation by fluoxetine, while both iHi and vHi play distinct roles in fluoxetine-induced antidepressant-like behaviors. |
| first_indexed | 2024-12-17T04:08:14Z |
| format | Article |
| id | doaj.art-5765f13b5e53474ebbdb8a06db707c43 |
| institution | Directory Open Access Journal |
| issn | 2352-2895 |
| language | English |
| last_indexed | 2024-12-17T04:08:14Z |
| publishDate | 2021-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Neurobiology of Stress |
| spelling | doaj.art-5765f13b5e53474ebbdb8a06db707c432022-12-21T22:04:17ZengElsevierNeurobiology of Stress2352-28952021-05-0114100331Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effectsBrunno Rocha Levone0Gerard M. Moloney1John F. Cryan2Olivia F. O'Leary3Department of Anatomy and Neuroscience, University College Cork, Cork, IrelandDepartment of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, IrelandDepartment of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland; Corresponding author. Dept. of Anatomy and Neuroscience, Room 386, Western Gateway Building, University College Cork, Ireland.Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Corresponding author. Dept. of Anatomy and Neuroscience, Room 4.114, Western Gateway Building, University College Cork, Ireland.Current antidepressants are suboptimal due incomplete understanding of the neurobiology underlying their behavioral effects. However, imaging studies suggest the hippocampus is a key brain region underpinning antidepressant action. There is increasing attention on the functional segregation of the hippocampus into a dorsal region (dHi) predominantly involved in spatial learning and memory, and a ventral region (vHi) which regulates anxiety, a symptom often co-morbid with depression. However, little is known about the roles of these hippocampal sub-regions in the antidepressant response. Moreover, the area between them, the intermediate hippocampus (iHi), has received little attention. Here, we investigated the impact of dHi, iHi or vHi lesions on anxiety- and depressive-like behaviors under baseline or antidepressant treatment conditions in male C57BL/6 mice (n = 8–10). We found that in the absence of fluoxetine, vHi lesions reduced anxiety-like behavior, while none of the lesions affected other antidepressant-sensitive behaviors. vHi lesions prevented the acute antidepressant-like behavioral effects of fluoxetine in the tail suspension test and its anxiolytic effects in the novelty-induced hypophagia test. Intriguingly, only iHi lesions prevented the antidepressant effects of chronic fluoxetine treatment in the forced swim test. dHi lesions did not impact any behaviors either in the absence or presence of fluoxetine. In summary, we found that vHi plays a key role in anxiety-like behavior and its modulation by fluoxetine, while both iHi and vHi play distinct roles in fluoxetine-induced antidepressant-like behaviors.http://www.sciencedirect.com/science/article/pii/S2352289521000394Intermediate hippocampusVentral hippocampusAntidepressantDepressionAnxiety |
| spellingShingle | Brunno Rocha Levone Gerard M. Moloney John F. Cryan Olivia F. O'Leary Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effects Neurobiology of Stress Intermediate hippocampus Ventral hippocampus Antidepressant Depression Anxiety |
| title | Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effects |
| title_full | Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effects |
| title_fullStr | Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effects |
| title_full_unstemmed | Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effects |
| title_short | Specific sub-regions along the longitudinal axis of the hippocampus mediate antidepressant-like behavioral effects |
| title_sort | specific sub regions along the longitudinal axis of the hippocampus mediate antidepressant like behavioral effects |
| topic | Intermediate hippocampus Ventral hippocampus Antidepressant Depression Anxiety |
| url | http://www.sciencedirect.com/science/article/pii/S2352289521000394 |
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