Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod
Abstract: In reindeer Rangifer tarandus , a high latitude species, the rhythmic production of melatonin periodically dissipates under natural photoperiods when, in mid‐winter, there is near permanent darkness and again, in summer, when there is permanent light. In spring and autumn, as expected, mel...
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crwiley:10.1111/j.1600-079x.2007.00476.x 2024-04-21T08:10:43+00:00 Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod Stokkan, Karl‐Arne Van Oort, Bob E. H. Tyler, Nicholas J. C. Loudon, Andrew S. I. 2007 http://dx.doi.org/10.1111/j.1600-079x.2007.00476.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-079X.2007.00476.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-079X.2007.00476.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Pineal Research volume 43, issue 3, page 289-293 ISSN 0742-3098 1600-079X Endocrinology journal-article 2007 crwiley https://doi.org/10.1111/j.1600-079x.2007.00476.x 2024-03-28T08:27:44Z Abstract: In reindeer Rangifer tarandus , a high latitude species, the rhythmic production of melatonin periodically dissipates under natural photoperiods when, in mid‐winter, there is near permanent darkness and again, in summer, when there is permanent light. In spring and autumn, as expected, melatonin production reflects the ambient light:dark (LD) cycle. We investigated the expression of circadian mechanisms on blood levels of melatonin in reindeer. Two experiments were conducted in which animals were transferred from natural photic conditions into continuous darkness for 3 days: (i) in February, when they had been exposed to an LD cycle (11L:13D) and (ii) in July, when they had been exposed to permanent light. In July, plasma levels of melatonin rose abruptly on exposure to darkness but then declined over 24 hr before displaying a second rise and decline over the following 36 hr. In contrast, in February, levels of melatonin rose abruptly but then remained elevated for more than 60 hr in darkness. Melatonin secretion upon exposure to darkness did not conform to a circadian pattern and did not, therefore, support the hypothesis that pineal activity in reindeer is tightly regulated by circadian mechanisms. Instead the secretion of melatonin appeared to be acutely and directly sensitive to ambient lighting. The results are consistent with a model in which Arctic resident animals have adapted to extreme photic conditions by disconnecting the generation of the pineal melatonin signal from their circadian machinery and relying, instead, on its being driven by the LD cycle for just a few weeks annually in spring and autumn. Article in Journal/Newspaper Rangifer tarandus Wiley Online Library Journal of Pineal Research 43 3 289 293 |
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Wiley Online Library |
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crwiley |
language |
English |
topic |
Endocrinology |
spellingShingle |
Endocrinology Stokkan, Karl‐Arne Van Oort, Bob E. H. Tyler, Nicholas J. C. Loudon, Andrew S. I. Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod |
topic_facet |
Endocrinology |
description |
Abstract: In reindeer Rangifer tarandus , a high latitude species, the rhythmic production of melatonin periodically dissipates under natural photoperiods when, in mid‐winter, there is near permanent darkness and again, in summer, when there is permanent light. In spring and autumn, as expected, melatonin production reflects the ambient light:dark (LD) cycle. We investigated the expression of circadian mechanisms on blood levels of melatonin in reindeer. Two experiments were conducted in which animals were transferred from natural photic conditions into continuous darkness for 3 days: (i) in February, when they had been exposed to an LD cycle (11L:13D) and (ii) in July, when they had been exposed to permanent light. In July, plasma levels of melatonin rose abruptly on exposure to darkness but then declined over 24 hr before displaying a second rise and decline over the following 36 hr. In contrast, in February, levels of melatonin rose abruptly but then remained elevated for more than 60 hr in darkness. Melatonin secretion upon exposure to darkness did not conform to a circadian pattern and did not, therefore, support the hypothesis that pineal activity in reindeer is tightly regulated by circadian mechanisms. Instead the secretion of melatonin appeared to be acutely and directly sensitive to ambient lighting. The results are consistent with a model in which Arctic resident animals have adapted to extreme photic conditions by disconnecting the generation of the pineal melatonin signal from their circadian machinery and relying, instead, on its being driven by the LD cycle for just a few weeks annually in spring and autumn. |
format |
Article in Journal/Newspaper |
author |
Stokkan, Karl‐Arne Van Oort, Bob E. H. Tyler, Nicholas J. C. Loudon, Andrew S. I. |
author_facet |
Stokkan, Karl‐Arne Van Oort, Bob E. H. Tyler, Nicholas J. C. Loudon, Andrew S. I. |
author_sort |
Stokkan, Karl‐Arne |
title |
Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod |
title_short |
Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod |
title_full |
Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod |
title_fullStr |
Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod |
title_full_unstemmed |
Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod |
title_sort |
adaptations for life in the arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod |
publisher |
Wiley |
publishDate |
2007 |
url |
http://dx.doi.org/10.1111/j.1600-079x.2007.00476.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-079X.2007.00476.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-079X.2007.00476.x |
genre |
Rangifer tarandus |
genre_facet |
Rangifer tarandus |
op_source |
Journal of Pineal Research volume 43, issue 3, page 289-293 ISSN 0742-3098 1600-079X |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1600-079x.2007.00476.x |
container_title |
Journal of Pineal Research |
container_volume |
43 |
container_issue |
3 |
container_start_page |
289 |
op_container_end_page |
293 |
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1796952285185572864 |