Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala

Morten Jensen; Cecilia Ratner; Olga Rudenko; Søren H Christiansen; Louise J Skov; Cecilie  Hundahl; David P D Woldbye; Birgitte Holst

doi:10.1093/ijnp/pyv123

Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala

Morten Jensen, Cecilia Ratner, Olga Rudenko, Søren H Christiansen, Louise J Skov, Cecilie Hundahl, David P D Woldbye, Birgitte Holst

Neuropharm and Genetics

26 Citations (Scopus)

Abstract

Background: Besides the well-known effects of ghrelin on adiposity and food intake regulation, the ghrelin system has been shown to regulate aspects of behavior including anxiety and stress. However, the effect of virus-mediated overexpression of the ghrelin receptor in the amygdala has not previously been addressed directly. Methods: First, we examined the acute effect of peripheral ghrelin administration on anxiety- and depression-like behavior using the open field, elevated plus maze, forced swim, and tail suspension tests. Next, we examined the effect of peripheral ghrelin administration and ghrelin receptor deficiency on stress in a familiar and social environment using the Intellicage system. Importantly, we also used a novel approach to study ghrelin receptor signaling in the brain by overexpressing the ghrelin receptor in the amygdala. We examined the effect of ghrelin receptor overexpression on anxiety-related behavior before and after acute stress and measured the modulation of serotonin receptor expression. Results: We found that ghrelin caused an anxiolytic-like effect in both the open field and elevated plus maze tests. Additionally, it attenuated air-puff-induced stress in the social environment, while the opposite was shown in ghrelin receptor deficient mice. Finally, we found that overexpression of the ghrelin receptor in the basolateral division of the amygdala caused an anxiolytic-like effect and decreased the 5HT1a receptor expression. Conclusions: Ghrelin administration and overexpression of the ghrelin receptor in the amygdala induces anxiolytic-like behavior. Since the ghrelin receptor has high constitutive activity, ligand-independent signaling in vivo may be important for the observed anxiolytic-like effects. The anxiolytic effects seem to be mediated independently from the HPA axis, potentially engaging the central serotonin system.

Original language	English
Article number	pyv123
Journal	International Journal of Neuropsychopharmacology
Volume	19
Issue number	5
Number of pages	12
ISSN	1461-1457
DOIs	https://doi.org/10.1093/ijnp/pyv123
Publication status	Published - 1 May 2016

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10.1093/ijnp/pyv123Licence: CC BY-NC

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@article{c57651f4ec604eb1985feab87faa1a82,

title = "Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala",

abstract = "Background: Besides the well-known effects of ghrelin on adiposity and food intake regulation, the ghrelin system has been shown to regulate aspects of behavior including anxiety and stress. However, the effect of virus-mediated overexpression of the ghrelin receptor in the amygdala has not previously been addressed directly. Methods: First, we examined the acute effect of peripheral ghrelin administration on anxiety- and depression-like behavior using the open field, elevated plus maze, forced swim, and tail suspension tests. Next, we examined the effect of peripheral ghrelin administration and ghrelin receptor deficiency on stress in a familiar and social environment using the Intellicage system. Importantly, we also used a novel approach to study ghrelin receptor signaling in the brain by overexpressing the ghrelin receptor in the amygdala. We examined the effect of ghrelin receptor overexpression on anxiety-related behavior before and after acute stress and measured the modulation of serotonin receptor expression. Results: We found that ghrelin caused an anxiolytic-like effect in both the open field and elevated plus maze tests. Additionally, it attenuated air-puff-induced stress in the social environment, while the opposite was shown in ghrelin receptor deficient mice. Finally, we found that overexpression of the ghrelin receptor in the basolateral division of the amygdala caused an anxiolytic-like effect and decreased the 5HT1a receptor expression. Conclusions: Ghrelin administration and overexpression of the ghrelin receptor in the amygdala induces anxiolytic-like behavior. Since the ghrelin receptor has high constitutive activity, ligand-independent signaling in vivo may be important for the observed anxiolytic-like effects. The anxiolytic effects seem to be mediated independently from the HPA axis, potentially engaging the central serotonin system.",

author = "Morten Jensen and Cecilia Ratner and Olga Rudenko and Christiansen, {S{\o}ren H} and Skov, {Louise J} and Cecilie Hundahl and Woldbye, {David P D} and Birgitte Holst",

note = "{\textcopyright} The Author 2015. Published by Oxford University Press on behalf of CINP.",

year = "2016",

month = may,

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doi = "10.1093/ijnp/pyv123",

language = "English",

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journal = "International Journal of Neuropsychopharmacology",

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T1 - Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala

AU - Jensen, Morten

AU - Ratner, Cecilia

AU - Rudenko, Olga

AU - Christiansen, Søren H

AU - Skov, Louise J

AU - Hundahl, Cecilie

AU - Woldbye, David P D

AU - Holst, Birgitte

PY - 2016/5/1

Y1 - 2016/5/1

N2 - Background: Besides the well-known effects of ghrelin on adiposity and food intake regulation, the ghrelin system has been shown to regulate aspects of behavior including anxiety and stress. However, the effect of virus-mediated overexpression of the ghrelin receptor in the amygdala has not previously been addressed directly. Methods: First, we examined the acute effect of peripheral ghrelin administration on anxiety- and depression-like behavior using the open field, elevated plus maze, forced swim, and tail suspension tests. Next, we examined the effect of peripheral ghrelin administration and ghrelin receptor deficiency on stress in a familiar and social environment using the Intellicage system. Importantly, we also used a novel approach to study ghrelin receptor signaling in the brain by overexpressing the ghrelin receptor in the amygdala. We examined the effect of ghrelin receptor overexpression on anxiety-related behavior before and after acute stress and measured the modulation of serotonin receptor expression. Results: We found that ghrelin caused an anxiolytic-like effect in both the open field and elevated plus maze tests. Additionally, it attenuated air-puff-induced stress in the social environment, while the opposite was shown in ghrelin receptor deficient mice. Finally, we found that overexpression of the ghrelin receptor in the basolateral division of the amygdala caused an anxiolytic-like effect and decreased the 5HT1a receptor expression. Conclusions: Ghrelin administration and overexpression of the ghrelin receptor in the amygdala induces anxiolytic-like behavior. Since the ghrelin receptor has high constitutive activity, ligand-independent signaling in vivo may be important for the observed anxiolytic-like effects. The anxiolytic effects seem to be mediated independently from the HPA axis, potentially engaging the central serotonin system.

AB - Background: Besides the well-known effects of ghrelin on adiposity and food intake regulation, the ghrelin system has been shown to regulate aspects of behavior including anxiety and stress. However, the effect of virus-mediated overexpression of the ghrelin receptor in the amygdala has not previously been addressed directly. Methods: First, we examined the acute effect of peripheral ghrelin administration on anxiety- and depression-like behavior using the open field, elevated plus maze, forced swim, and tail suspension tests. Next, we examined the effect of peripheral ghrelin administration and ghrelin receptor deficiency on stress in a familiar and social environment using the Intellicage system. Importantly, we also used a novel approach to study ghrelin receptor signaling in the brain by overexpressing the ghrelin receptor in the amygdala. We examined the effect of ghrelin receptor overexpression on anxiety-related behavior before and after acute stress and measured the modulation of serotonin receptor expression. Results: We found that ghrelin caused an anxiolytic-like effect in both the open field and elevated plus maze tests. Additionally, it attenuated air-puff-induced stress in the social environment, while the opposite was shown in ghrelin receptor deficient mice. Finally, we found that overexpression of the ghrelin receptor in the basolateral division of the amygdala caused an anxiolytic-like effect and decreased the 5HT1a receptor expression. Conclusions: Ghrelin administration and overexpression of the ghrelin receptor in the amygdala induces anxiolytic-like behavior. Since the ghrelin receptor has high constitutive activity, ligand-independent signaling in vivo may be important for the observed anxiolytic-like effects. The anxiolytic effects seem to be mediated independently from the HPA axis, potentially engaging the central serotonin system.

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DO - 10.1093/ijnp/pyv123

M3 - Journal article

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SN - 1461-1457

VL - 19

JO - International Journal of Neuropsychopharmacology

JF - International Journal of Neuropsychopharmacology

IS - 5

M1 - pyv123

ER -

Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala

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