title: Seasonal induction of GABAergic excitation in the central mammalian clock.
abstract: The balance between excitation and inhibition is essential for the proper function of neuronal networks in the brain. The inhibitory neurotransmitter γ-aminobutyric acid (GABA) contributes to the network dynamics within the suprachiasmatic nucleus (SCN), which is involved in seasonal encoding. We investigated GABAergic activity and observed mainly inhibitory action in SCN neurons of mice exposed to a short-day photoperiod. Remarkably, the GABAergic activity in a long-day photoperiod shifts from inhibition toward excitation. The mechanistic basis for this appears to be a change in the equilibrium potential of GABA-evoked current. These results emphasize that environmental conditions can have substantial effects on the function of a key neurotransmitter in the central nervous system.
authors: Department of Molecular Cell Biology, Laboratory of Neurophysiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
authors: Sahar
authors: S
authors: Farajnia
authors: Department of Molecular Cell Biology, Laboratory of Neurophysiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
authors: Tirsa L E
authors: TL
authors: van Westering
authors: Department of Molecular Cell Biology, Laboratory of Neurophysiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
authors: Johanna H
authors: JH
authors: Meijer
authors: Department of Molecular Cell Biology, Laboratory of Neurophysiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands S.michel@lumc.nl.
authors: Stephan
authors: S
authors: Michel
mesh_terms: D000818:Animals; D057906:Circadian Clocks / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D053444:Inhibitory Postsynaptic Potentials / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D018408:Patch-Clamp Techniques; D017440:Photoperiod; D012621:Seasons; D018709:Statistics, Nonparametric; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D005680:gamma-Aminobutyric Acid
keywords: NKCC1; calcium; chloride; circadian; excitation/inhibition balance