GABAB Receptor Stimulation Phase-shifts the Mammalian Circadian Clock In Vitro
The mammalian circadian clock in the suprachiasmatic nucleus (SCN) generates 24-h rhythms in vitro. Here we show that the GABAB agonist baclofen resets the SCN pacemaker in vitro in a phase-dependent manner: advances were induced at zeitgeber time (ZT) 6, and delays were induced at ZT 22. Both effects were blocked the GABAB antagonist, 2-hydroxysaclofen, while the GABAA antagonist, bicuculline was ineffective. Thus, the SCN pacemaker is sensitive to resetting by GABAB stimulation.
Kevin R. Biggs, Rebecca A. Prosser, GABAB receptor stimulation phase-shifts the mammalian circadian clock in vitro, Brain Research, Volume 807, Issues 1-2, 5 October 1998, Pages 250-254, ISSN 0006-8993, DOI: 10.1016/S0006-8993(98)00820-8. (http://www.sciencedirect.com/science/article/B6SYR-3TWYPXD-21/2/9bf16d500e38e63e465beae6f13f101a)