Differential Sensitivity to Ethanol-Induced Circadian Rhythm Disruption in Adolescent and Adult Mice.

Published

Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Ruby, CL; Palmer, KN; Zhang, J; Risinger, MO; Butkowski, MA; Swartzwelder, HS

Published Date

  • January 2017

Published In

Volume / Issue

  • 41 / 1

Start / End Page

  • 187 - 196

PubMed ID

  • 27997028

Pubmed Central ID

  • 27997028

Electronic International Standard Serial Number (EISSN)

  • 1530-0277

Digital Object Identifier (DOI)

  • 10.1111/acer.13275

Language

  • eng

Conference Location

  • England