The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula.
BACKGROUND:Laboratory conditions nullify the extrinsic factors that determine the wild expected lifespan and release the intrinsic or potential lifespan. Thus, wild animals reared in a laboratory often show an increased lifespan, and consequently an increased senescence phase. Senescence is associat...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2009-06-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC2690841?pdf=render |
| _version_ | 1819177306205192192 |
|---|---|
| author | Elodie Magnanou Joël Attia Roger Fons Gilles Boeuf Jack Falcon |
| author_facet | Elodie Magnanou Joël Attia Roger Fons Gilles Boeuf Jack Falcon |
| author_sort | Elodie Magnanou |
| collection | DOAJ |
| description | BACKGROUND:Laboratory conditions nullify the extrinsic factors that determine the wild expected lifespan and release the intrinsic or potential lifespan. Thus, wild animals reared in a laboratory often show an increased lifespan, and consequently an increased senescence phase. Senescence is associated with a broad suite of physiological changes, including a decreased responsiveness of the circadian system. The time-keeping hormone melatonin, an important chemical player in this system, is suspected to have an anti-aging role. The Greater White-toothed shrew Crocidura russula is an ideal study model to address questions related to aging and associated changes in biological functions: its lifespan is short and is substantially increased in captivity; daily and seasonal rhythms, while very marked the first year of life, are dramatically altered during the senescence process which starts during the second year. Here we report on an investigation of the effects of melatonin administration on locomotor activity of aging shrews. METHODOLOGY/PRINCIPAL FINDINGS:1) The diel fluctuations of melatonin levels in young, adult and aging shrews were quantified in the pineal gland and plasma. In both, a marked diel rhythm (low diurnal concentration; high nocturnal concentration) was present in young animals but then decreased in adults, and, as a result of a loss in the nocturnal production, was absent in old animals. 2) Daily locomotor activity rhythm was monitored in pre-senescent animals that had received either a subcutaneous melatonin implant, an empty implant or no implant at all. In non-implanted and sham-implanted shrews, the rhythm was well marked in adults. A marked degradation in both period and amplitude, however, started after the age of 14-16 months. This pattern was considerably delayed in melatonin-implanted shrews who maintained the daily rhythm for significantly longer. CONCLUSIONS:This is the first long term study (>500 days observation of the same individuals) that investigates the effects of continuous melatonin delivery. As such, it sheds new light on the putative anti-aging role of melatonin by demonstrating that continuous melatonin administration delays the onset of senescence. In addition, the shrew appears to be a promising mammalian model for elucidating the precise relationships between melatonin and aging. |
| first_indexed | 2024-12-22T21:24:33Z |
| format | Article |
| id | doaj.art-20adbce5ce574cf48be062927fd705b4 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-22T21:24:33Z |
| publishDate | 2009-06-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-20adbce5ce574cf48be062927fd705b42022-12-21T18:12:05ZengPublic Library of Science (PLoS)PLoS ONE1932-62032009-06-0146e590410.1371/journal.pone.0005904The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula.Elodie MagnanouJoël AttiaRoger FonsGilles BoeufJack FalconBACKGROUND:Laboratory conditions nullify the extrinsic factors that determine the wild expected lifespan and release the intrinsic or potential lifespan. Thus, wild animals reared in a laboratory often show an increased lifespan, and consequently an increased senescence phase. Senescence is associated with a broad suite of physiological changes, including a decreased responsiveness of the circadian system. The time-keeping hormone melatonin, an important chemical player in this system, is suspected to have an anti-aging role. The Greater White-toothed shrew Crocidura russula is an ideal study model to address questions related to aging and associated changes in biological functions: its lifespan is short and is substantially increased in captivity; daily and seasonal rhythms, while very marked the first year of life, are dramatically altered during the senescence process which starts during the second year. Here we report on an investigation of the effects of melatonin administration on locomotor activity of aging shrews. METHODOLOGY/PRINCIPAL FINDINGS:1) The diel fluctuations of melatonin levels in young, adult and aging shrews were quantified in the pineal gland and plasma. In both, a marked diel rhythm (low diurnal concentration; high nocturnal concentration) was present in young animals but then decreased in adults, and, as a result of a loss in the nocturnal production, was absent in old animals. 2) Daily locomotor activity rhythm was monitored in pre-senescent animals that had received either a subcutaneous melatonin implant, an empty implant or no implant at all. In non-implanted and sham-implanted shrews, the rhythm was well marked in adults. A marked degradation in both period and amplitude, however, started after the age of 14-16 months. This pattern was considerably delayed in melatonin-implanted shrews who maintained the daily rhythm for significantly longer. CONCLUSIONS:This is the first long term study (>500 days observation of the same individuals) that investigates the effects of continuous melatonin delivery. As such, it sheds new light on the putative anti-aging role of melatonin by demonstrating that continuous melatonin administration delays the onset of senescence. In addition, the shrew appears to be a promising mammalian model for elucidating the precise relationships between melatonin and aging.http://europepmc.org/articles/PMC2690841?pdf=render |
| spellingShingle | Elodie Magnanou Joël Attia Roger Fons Gilles Boeuf Jack Falcon The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula. PLoS ONE |
| title | The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula. |
| title_full | The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula. |
| title_fullStr | The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula. |
| title_full_unstemmed | The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula. |
| title_short | The timing of the shrew: continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula. |
| title_sort | timing of the shrew continuous melatonin treatment maintains youthful rhythmic activity in aging crocidura russula |
| url | http://europepmc.org/articles/PMC2690841?pdf=render |
| work_keys_str_mv | AT elodiemagnanou thetimingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT joelattia thetimingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT rogerfons thetimingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT gillesboeuf thetimingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT jackfalcon thetimingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT elodiemagnanou timingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT joelattia timingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT rogerfons timingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT gillesboeuf timingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula AT jackfalcon timingoftheshrewcontinuousmelatonintreatmentmaintainsyouthfulrhythmicactivityinagingcrocidurarussula |