BACKGROUND: Growing evidence supports a central role for the circadian system in alcohol use disorders, but few studies have examined this relationship during adolescence. In mammals, circadian rhythms are regulated by the suprachiasmatic nucleus, a biological clock whose timing is synchronized (reset) to the environment primarily by light (photic) input. Alcohol (ethanol [EtOH]) disrupts circadian timing in part by attenuating photic phase-resetting responses in adult rodents. However, circadian rhythms change throughout life and it is not yet known whether EtOH has similar effects on circadian regulation during adolescence. METHODS: General circadian locomotor activity was monitored in male C57BL6/J mice beginning in adolescence (P27) or adulthood (P61) in a 12-hour light, 12-hour dark photocycle for ~2 weeks to establish baseline circadian activity measures. On the day of the experiment, mice received an acute injection of EtOH (1.5 g/kg, i.p.) or equal volume saline 15 minutes prior to a 30-minute light pulse at Zeitgeber Time 14 (2 hours into the dark phase) and then were released into constant darkness (DD) for ~2 weeks to assess phase-resetting responses. Control mice of each age-group received injections but no light pulse prior to DD. RESULTS: While adults showed the expected decrease in photic phase-delays induced by acute EtOH, this effect was absent in adolescent mice. Adolescents also showed baseline differences in circadian rhythmicity compared to adults, including advanced photocycle entrainment, larger photic phase-delays, a shorter free-running (endogenous) circadian period, and greater circadian rhythm amplitude. CONCLUSIONS: Collectively, our results indicate that adolescent mice are less sensitive to the effect of EtOH on circadian photic phase-resetting and that their daily activity rhythms are markedly different than those of adults.
BACKGROUND: Growing evidence supports a central role for the circadian system in alcohol use disorders, but few studies have examined this relationship during adolescence. In mammals, circadian rhythms are regulated by the suprachiasmatic nucleus, a biological clock whose timing is synchronized (reset) to the environment primarily by light (photic) input. Alcohol (ethanol [EtOH]) disrupts circadian timing in part by attenuating photic phase-resetting responses in adult rodents. However, circadian rhythms change throughout life and it is not yet known whether EtOH has similar effects on circadian regulation during adolescence. METHODS: General circadian locomotor activity was monitored in male C57BL6/J mice beginning in adolescence (P27) or adulthood (P61) in a 12-hour light, 12-hour dark photocycle for ~2 weeks to establish baseline circadian activity measures. On the day of the experiment, mice received an acute injection of EtOH (1.5 g/kg, i.p.) or equal volume saline 15 minutes prior to a 30-minute light pulse at Zeitgeber Time 14 (2 hours into the dark phase) and then were released into constant darkness (DD) for ~2 weeks to assess phase-resetting responses. Control mice of each age-group received injections but no light pulse prior to DD. RESULTS: While adults showed the expected decrease in photic phase-delays induced by acute EtOH, this effect was absent in adolescent mice. Adolescents also showed baseline differences in circadian rhythmicity compared to adults, including advanced photocycle entrainment, larger photic phase-delays, a shorter free-running (endogenous) circadian period, and greater circadian rhythm amplitude. CONCLUSIONS: Collectively, our results indicate that adolescent mice are less sensitive to the effect of EtOH on circadian photic phase-resetting and that their daily activity rhythms are markedly different than those of adults.
Authors: Eileen M Moore; John N Mariani; David N Linsenbardt; Laverne C Melón; Stephen L Boehm Journal: Alcohol Clin Exp Res Date: 2010-01-26 Impact factor: 3.455
Authors: Kati L Healey; Sandra A Kibble; Amelia Bell; George Kramer; Antoniette Maldonado-Devincci; H S Swartzwelder Journal: Alcohol Date: 2021-11-19 Impact factor: 2.405
Authors: Christina L Ruby; Gerneleh Paye; Jason L Fabi; Jiawen Zhang; Megan O Risinger; Kaitlyn N Palmer; Natalie M Verbanes; Ariana D'Angelo; Tia M Watts; Lauren Mabe; H Scott Swartzwelder Journal: Alcohol Clin Exp Res Date: 2018-09-02 Impact factor: 3.455
Authors: Donita L Robinson; Leslie R Amodeo; L Judson Chandler; Fulton T Crews; Cindy L Ehlers; Alexander Gómez-A; Kati L Healey; Cynthia M Kuhn; Victoria A Macht; S Alexander Marshall; H Scott Swartzwelder; Elena I Varlinskaya; David F Werner Journal: Int Rev Neurobiol Date: 2021-08-11 Impact factor: 4.280