TTX Blocks Baclofen-induced Phase Shifts of the Mammalian Circadian Pacemaker in Vitro

Authors

Rebecca Prosser, University of Tennessee - Knoxville
Harriet E. Bergeron, University of Tennessee - KnoxvilleFollow
Blaine Danielson, University of Tennessee - Knoxville
Kevin R. Biggs, University of Tennessee - Knoxville

Document Type

Article

Publication Date

9-1999

Abstract

The mammalian circadian pacemaker, located in the suprachiasmatic nucleus (SCN), expresses 24-h rhythms when isolated in vitro. The GABA_A agonist, muscimol, induces phase advances during the mid-subjective day, while the GABA_B agonist, baclofen, induces both daytime phase advances and nighttime phase delays. Here, we present evidence that tetrodotoxin (TTX) completely blocks baclofen-induced phase shifts in vitro, but does not block in vitro phase advances induced by muscimol. These results suggest that GABA_A, but not GABA_B, receptors are located on SCN pacemaker cells.

Recommended Citation

Harriet E. Bergeron, Blaine Danielson, Kevin R. Biggs, Rebecca A. Prosser, TTX blocks baclofen-induced phase shifts of the mammalian circadian pacemaker in vitro, Brain Research, Volume 841, Issues 1-2, 11 September 1999, Pages 193-196, ISSN 0006-8993, DOI: 10.1016/S0006-8993(99)01791-6. (http://www.sciencedirect.com/science/article/B6SYR-3XMGP1C-1N/2/e38cabf25c7bc2f309425678bcb83f89)