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.
Department of Zoology, University of Tennessee, Knoxville, TN 37996, USA.
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D000818:Animals; D001418:Baclofen / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000187:drug effects*; D018755:GABA Agonists / Q000494:pharmacology*; D058786:GABA-B Receptor Agonists; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013268:Stimulation, Chemical; D013493:Suprachiasmatic Nucleus / Q000187:drug effects*
D018755:GABA Agonists; D058786:GABA-B Receptor Agonists; D001418:Baclofen