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
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 prod...
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ftumanchesterpub:oai:pure.atira.dk:publications/68f3c5b4-48ad-4734-acc3-62319e157d14 2023-11-12T04:10:00+01:00 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 2007-10 https://research.manchester.ac.uk/en/publications/68f3c5b4-48ad-4734-acc3-62319e157d14 https://doi.org/10.1111/j.1600-079X.2007.00476.x eng eng info:eu-repo/semantics/closedAccess Stokkan , K A , Van Oort , B E H , Tyler , N J C & Loudon , A S I 2007 , ' 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 ' , Journal of Pineal Research , vol. 43 , no. 3 , pp. 289-293 . https://doi.org/10.1111/j.1600-079X.2007.00476.x Adaptation Arctic Circadian Melatonin Reindeer article 2007 ftumanchesterpub https://doi.org/10.1111/j.1600-079X.2007.00476.x 2023-10-30T09:12:59Z 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. © 2007 The Authors. Article in Journal/Newspaper Arctic Arctic Rangifer tarandus The University of Manchester: Research Explorer Arctic Journal of Pineal Research 43 3 289 293 |
institution |
Open Polar |
collection |
The University of Manchester: Research Explorer |
op_collection_id |
ftumanchesterpub |
language |
English |
topic |
Adaptation Arctic Circadian Melatonin Reindeer |
spellingShingle |
Adaptation Arctic Circadian Melatonin Reindeer 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 |
Adaptation Arctic Circadian Melatonin Reindeer |
description |
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. © 2007 The Authors. |
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 |
publishDate |
2007 |
url |
https://research.manchester.ac.uk/en/publications/68f3c5b4-48ad-4734-acc3-62319e157d14 https://doi.org/10.1111/j.1600-079X.2007.00476.x |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Arctic Rangifer tarandus |
genre_facet |
Arctic Arctic Rangifer tarandus |
op_source |
Stokkan , K A , Van Oort , B E H , Tyler , N J C & Loudon , A S I 2007 , ' 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 ' , Journal of Pineal Research , vol. 43 , no. 3 , pp. 289-293 . https://doi.org/10.1111/j.1600-079X.2007.00476.x |
op_rights |
info:eu-repo/semantics/closedAccess |
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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