Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF
Thermoregulation is necessary to maintain energy homeostasis. The novel discovery of brown adipose tissue (BAT) in humans has increased research interests in better understanding BAT thermogenesis to restore energy balance in metabolic disorders. The hibernating Arctic ground squirrel (AGS) offers a...
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2018
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Online Access: | https://doi.org/10.3389/fphys.2018.01747.s002 https://figshare.com/articles/Image_2_The_Raphe_Pallidus_and_the_Hypothalamic-Pituitary-Thyroid_Axis_Gate_Seasonal_Changes_in_Thermoregulation_in_the_Hibernating_Arctic_Ground_Squirrel_Urocitellus_parryii_TIF/7453280 |
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ftfrontimediafig:oai:figshare.com:article/7453280 2023-05-15T14:31:29+02:00 Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF Carla Frare Mackenzie E. Jenkins Steven J. Soldin Kelly L. Drew 2018-12-12T04:08:40Z https://doi.org/10.3389/fphys.2018.01747.s002 https://figshare.com/articles/Image_2_The_Raphe_Pallidus_and_the_Hypothalamic-Pituitary-Thyroid_Axis_Gate_Seasonal_Changes_in_Thermoregulation_in_the_Hibernating_Arctic_Ground_Squirrel_Urocitellus_parryii_TIF/7453280 unknown doi:10.3389/fphys.2018.01747.s002 https://figshare.com/articles/Image_2_The_Raphe_Pallidus_and_the_Hypothalamic-Pituitary-Thyroid_Axis_Gate_Seasonal_Changes_in_Thermoregulation_in_the_Hibernating_Arctic_Ground_Squirrel_Urocitellus_parryii_TIF/7453280 CC BY 4.0 CC-BY Physiology Exercise Physiology Nutritional Physiology Reproduction Cell Physiology Systems Physiology Animal Physiology - Biophysics Animal Physiology - Cell Animal Physiology - Systems Comparative Physiology Physiology not elsewhere classified season hibernation thyroid hormones thermoregulation thermogenic capacity SNS raphe pallidus adenosine Image Figure 2018 ftfrontimediafig https://doi.org/10.3389/fphys.2018.01747.s002 2018-12-12T23:58:28Z Thermoregulation is necessary to maintain energy homeostasis. The novel discovery of brown adipose tissue (BAT) in humans has increased research interests in better understanding BAT thermogenesis to restore energy balance in metabolic disorders. The hibernating Arctic ground squirrel (AGS) offers a novel approach to investigate BAT thermogenesis. AGS seasonally increase their BAT mass to increase the ability to generate heat during interbout arousals. The mechanisms promoting the seasonal changes in BAT thermogenesis are not well understood. BAT thermogenesis is regulated by the raphe pallidus (rPA) and by thyroid hormones produced by the hypothalamic–pituitary–thyroid (HPT) axis. Here, we investigate if the HPT axis and the rPA undergo seasonal changes to modulate BAT thermogenesis in hibernation. We used histological analysis and tandem mass spectrometry to assess activation of the HPT axis and immunohistochemistry to measure neuronal activation. We found an increase in HPT axis activation in fall and in response to pharmacologically induced torpor when adenosine A 1 receptor agonist was administered in winter. By contrast, the rPA neuronal activation was lower in winter in response to pharmacologically induced torpor. Activation of the rPA was also lower in winter compared to the other seasons. Our results suggest that thermogenic capacity develops during fall as the HPT axis is activated to reach maximum capacity in winter seen by increased free thyroid hormones in response to cooling. However, thermogenesis is inhibited during torpor as sympathetic premotor neuronal activation is lower in winter, until arousal when inhibition of thermogenesis is relieved. These findings describe seasonal modulation of thermoregulation that conserves energy through attenuated sympathetic drive, but retains heat generating capacity through activation of the HPT axis. Still Image Arctic ground squirrel Arctic Urocitellus parryii Frontiers: Figshare Arctic |
institution |
Open Polar |
collection |
Frontiers: Figshare |
op_collection_id |
ftfrontimediafig |
language |
unknown |
topic |
Physiology Exercise Physiology Nutritional Physiology Reproduction Cell Physiology Systems Physiology Animal Physiology - Biophysics Animal Physiology - Cell Animal Physiology - Systems Comparative Physiology Physiology not elsewhere classified season hibernation thyroid hormones thermoregulation thermogenic capacity SNS raphe pallidus adenosine |
spellingShingle |
Physiology Exercise Physiology Nutritional Physiology Reproduction Cell Physiology Systems Physiology Animal Physiology - Biophysics Animal Physiology - Cell Animal Physiology - Systems Comparative Physiology Physiology not elsewhere classified season hibernation thyroid hormones thermoregulation thermogenic capacity SNS raphe pallidus adenosine Carla Frare Mackenzie E. Jenkins Steven J. Soldin Kelly L. Drew Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF |
topic_facet |
Physiology Exercise Physiology Nutritional Physiology Reproduction Cell Physiology Systems Physiology Animal Physiology - Biophysics Animal Physiology - Cell Animal Physiology - Systems Comparative Physiology Physiology not elsewhere classified season hibernation thyroid hormones thermoregulation thermogenic capacity SNS raphe pallidus adenosine |
description |
Thermoregulation is necessary to maintain energy homeostasis. The novel discovery of brown adipose tissue (BAT) in humans has increased research interests in better understanding BAT thermogenesis to restore energy balance in metabolic disorders. The hibernating Arctic ground squirrel (AGS) offers a novel approach to investigate BAT thermogenesis. AGS seasonally increase their BAT mass to increase the ability to generate heat during interbout arousals. The mechanisms promoting the seasonal changes in BAT thermogenesis are not well understood. BAT thermogenesis is regulated by the raphe pallidus (rPA) and by thyroid hormones produced by the hypothalamic–pituitary–thyroid (HPT) axis. Here, we investigate if the HPT axis and the rPA undergo seasonal changes to modulate BAT thermogenesis in hibernation. We used histological analysis and tandem mass spectrometry to assess activation of the HPT axis and immunohistochemistry to measure neuronal activation. We found an increase in HPT axis activation in fall and in response to pharmacologically induced torpor when adenosine A 1 receptor agonist was administered in winter. By contrast, the rPA neuronal activation was lower in winter in response to pharmacologically induced torpor. Activation of the rPA was also lower in winter compared to the other seasons. Our results suggest that thermogenic capacity develops during fall as the HPT axis is activated to reach maximum capacity in winter seen by increased free thyroid hormones in response to cooling. However, thermogenesis is inhibited during torpor as sympathetic premotor neuronal activation is lower in winter, until arousal when inhibition of thermogenesis is relieved. These findings describe seasonal modulation of thermoregulation that conserves energy through attenuated sympathetic drive, but retains heat generating capacity through activation of the HPT axis. |
format |
Still Image |
author |
Carla Frare Mackenzie E. Jenkins Steven J. Soldin Kelly L. Drew |
author_facet |
Carla Frare Mackenzie E. Jenkins Steven J. Soldin Kelly L. Drew |
author_sort |
Carla Frare |
title |
Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF |
title_short |
Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF |
title_full |
Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF |
title_fullStr |
Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF |
title_full_unstemmed |
Image_2_The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel (Urocitellus parryii).TIF |
title_sort |
image_2_the raphe pallidus and the hypothalamic-pituitary-thyroid axis gate seasonal changes in thermoregulation in the hibernating arctic ground squirrel (urocitellus parryii).tif |
publishDate |
2018 |
url |
https://doi.org/10.3389/fphys.2018.01747.s002 https://figshare.com/articles/Image_2_The_Raphe_Pallidus_and_the_Hypothalamic-Pituitary-Thyroid_Axis_Gate_Seasonal_Changes_in_Thermoregulation_in_the_Hibernating_Arctic_Ground_Squirrel_Urocitellus_parryii_TIF/7453280 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic ground squirrel Arctic Urocitellus parryii |
genre_facet |
Arctic ground squirrel Arctic Urocitellus parryii |
op_relation |
doi:10.3389/fphys.2018.01747.s002 https://figshare.com/articles/Image_2_The_Raphe_Pallidus_and_the_Hypothalamic-Pituitary-Thyroid_Axis_Gate_Seasonal_Changes_in_Thermoregulation_in_the_Hibernating_Arctic_Ground_Squirrel_Urocitellus_parryii_TIF/7453280 |
op_rights |
CC BY 4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.3389/fphys.2018.01747.s002 |
_version_ |
1766305098492805120 |