title: The dynamics of GABA signaling: Revelations from the circadian pacemaker in the suprachiasmatic nucleus.
abstract: Virtually every neuron within the suprachiasmatic nucleus (SCN) communicates via GABAergic signaling. The extracellular levels of GABA within the SCN are determined by a complex interaction of synthesis and transport, as well as synaptic and non-synaptic release. The response to GABA is mediated by GABAAreceptors that respond to both phasic and tonic GABA release and that can produce excitatory as well as inhibitory cellular responses. GABA also influences circadian control through the exclusively inhibitory effects of GABABreceptors. Both GABA and neuropeptide signaling occur within the SCN, although the functional consequences of the interactions of these signals are not well understood. This review considers the role of GABA in the circadian pacemaker, in the mechanisms responsible for the generation of circadian rhythms, in the ability of non-photic stimuli to reset the phase of the pacemaker, and in the ability of the day-night cycle to entrain the pacemaker.
authors.affiliation: Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States. Electronic address: biohea@gsu.edu.
authors.forename: H Elliott
authors.initials: HE
authors.lastname: Albers
authors.affiliation: Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States.
authors.forename: James C
authors.initials: JC
authors.lastname: Walton
authors.affiliation: Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Gamble
authors.affiliation: Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States.
authors.forename: John K
authors.initials: JK
authors.lastname: McNeill
authors.affiliation: Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Department of Psychology, Morehouse College, Atlanta, GA 30314, United States.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Hummer
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D015398:Signal Transduction / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
chemical_list: D005680:gamma-Aminobutyric Acid
keywords: Benzodiazepines; Cation chloride cotransporters; Entrainment; Ethanol; GABA vesicular transporters; GABA(A) receptors; GABA(B) receptors; Glutamic acid decarboxylase; Membrane GABA transporters; Neurosteroids