. Author manuscript; available in PMC: 2018 Jan 1.

Published in final edited form as: Front Neuroendocrinol. 2016 Nov 25;44:35–82. doi: 10.1016/j.yfrne.2016.11.003

Table 3.

Cellular effects of GABA on SCN neurons.

Paper	LD cycle	Technique	Tissue preparation	GABA administration	Effects on SCN neurons
Shibata et al. (1983) PMID 6633950	12:12	Extracellular single unit recording	Slice preparation; PD11 and adult rats	GABA (iontophoresis)	GABA inhibited 97% of neurons examined. All recordings done during the day
Shibata et al. (1983) PMID 6668768	12:12	Extracellular single unit recording	Slice preparation; rats	GABA (iontophoresis)	GABA inhibited 90% and 4% were excited/inhibited; no differences in GABA effects in ventral versus dorsal SCN. All recordings done during the day
Mason (1986) PMID 3795084	12:12	Extracellular single-unit recording	Urethane anesthetized rats	GABA (iontophoresis)	No day-night variation in the inhibitory effects of GABA; the inhibitory effects of GABA were reduced in rats housed in constant light
Liou et al. (1990) PMID 1976421	12:12	Extracellular single unit recording	Slice preparation; rats	GABA (bath application)	Overall GABA inhibited 65% and excited 12%; 61% of neurons in the ventral SCN were inhibited and 69% of neurons in the dorsal SCN were inhibited
Liou and Albers (1990) PMID 2207720	14:10	Extracellular single unit recording	Slice preparation; hamsters	GABA (bath application)	GABA inhibited 55% and excited 7%; no differences between ventral and dorsal SCN; GABA altered firing in 48% of neurons during the day and 66% at night
Mason et al. (1991) PMID 1913180	12:12	Extracellular single unit recordings	Slice preparation; hamsters	GABA (iontophoresis)	GABA inhibited 92% with no effect in 8%; GABA inhibited firing in 98% during the day and 89% at night
Bos and Mirmiran (1993) PMID 8095843	Not noted	Extracellular single unit recordings	Cultured organotypic SCN slices prepared from PD12 rats	GABA (iontophoresis)	GABA inhibited 91%
Kawahara et al. (1993) PMID 8247331	Not noted	Whole-cell voltage- clamp	Dissociated culture of SCN neurons; PD21 rats	GABA (bath application)	GABA elicited inward currents in all neurons tested at a holding potential of −60 mV
Kawahara et al. (1994) PMID 7965836	Not noted	Whole-cell voltage- clamp	Dissociated culture of SCN neurons; PD23–28 rats	GABA (bath application)	GABA elicited inward currents in all neurons tested at a holding potential of −60 mV
Obrietan and van den Pol (1995) PMID 7623135	Not noted	Fura-2 Ca²⁺imaging	Dissociated culture of SCN neurons; ED18 rats	GABA (bath application)	GABA elevated Ca²⁺in embryonic SCN neurons
Obrietan and van den Pol (1996) PMID 8627385	Not noted	Fura-2 Ca²⁺imaging	Dissociated culture of SCN neurons; organotypic SCN cultures; ED19–21 rats	GABA (bath application)	GABA elevated Ca²⁺in embryonic SCN neurons maintained in dissociated and organotypic cultures
Shimura et al. (1996) PMID 8764156	12:12	Voltage-clamp condition of nystatin- perforated patch clamp recordings	Dissociated culture of SCN neurons; PD11–14 rats	GABA (bath application)	GABA induced inward currents at a holding potential of −40 mV
Wagner et al. (1997) PMID 9177347	12:12	Extracellular single unit recordings; whole cell patch clamp recordings	Slice preparation; PD21– 56 rats	GABA (bath application)	During the day GABA excited 71%, inhibited 16% and had no effect on 13%; during the night GABA excited 32%, inhibited 56% and had no effect on 12%; GABA increased the membrane conductance up to nine-fold throughout the day
Gribkoff et al. (1999) PMID 10194649	12:12	Multiple unit recordings; whole cell patch clamp recordings	Slice preparation; rats	GABA (bath application or pressure applied with a Picospritzer)	Multiple unit recordings found GABA inhibited firing during the day and night. In cell attached recordings during the day GABA inhibited nearly all action currents
Liu and Reppert (2000) PMID 10707977	12:12	Extracellular single unit recordings	Dissociated culture of SCN neurons; PD0–3 mice	GABA (bath application)	One or 6 h administration of GABA completely inhibited the firing rate of all neurons at all phases of the circadian cycle. One or 6 h of GABA treatment yielded patterns of phase shifts similar to each other. GABA produced maximal phase delays of 10 h and phase advances of 6 h
Wagner et al. (2001) PMID 11744760	12:12	Whole cell patch clamp recordings	Slice preparation; PD14– 28 rats	GABA (bath application and locally from a patch pipette using pressure injection)	Currents induced by GABA are carried by both chloride and bicarbonate ions; lack slow desensitization processes and are moderately voltage dependent; there are two independent mechanisms regulating chloride – one accumulating intracellular Ca²⁺and one removing; the mechanism reintroducing Ca²⁺is less efficient at night
De Jeu and Pennartz (2002) PMID 11826050	12:12	Gramicidin-perforated- patch clamp recordings	Slice preparation; rats	GABA (bath application)	During the day GABA produced hyperpolarization in 10/11 neurons. During the night GABA produced hyperpolarization in 7/12 and depolarization in 5/12
Shimura et al. (2002) PMID 11788348	12:12	Gramicidin- or nystatin- perforated-patch clamp recordings	Dissociated culture of SCN neurons; PD11,12 rats	GABA (bath application)	GABA induced an inward current at a holding potential of −40 mV
Gribkoff et al. (2003) PMID 12750413	12:12	Multiple unit recordings	Slice preparation; rats	GABA (bath application)	GABA produced exclusively inhibitory responses with no differences between day and night. Continuous administration of GABA inhibited firing rate for more than 1 h
Choi et al. (2008) PMID 18495878	12:12	Extracellular single unit and gramicidin- perforated-patch clamp recordings	Slice preparation; PD30– 40 rats	GABA (bath application)	Over the entire circadian cycle, GABA inhibited 72%, excited 15% and produced excitation followed by inhibition in 13%; GABA excitation present in ventral and dorsal SCN, excitatory responses most common in dorsal SCN at night. GABA increased Ca²⁺in 40% of neurons sampled during both the day and night
Irwin and Allen (2009) PMID 19821838	12:12	Fura-2 Ca²⁺imaging	Slice preparation; PD28– 42 rats	GABA (bath application)	GABA increases Ca²⁺in some neurons, decreases Ca²⁺in others and has no effect in still others. More neurons in which GABA increased Ca²⁺and fewer neurons in which GABA reduced Ca²⁺were found at night than during the day. GABA increased Ca²⁺more in neurons in the dorsal than the ventral SCN
Moldavan and Allen (2013) PMID 23401614	12:12	Whole cell patch clamp	Slice preparation prepared during the light period; rats	GABA (bath application)	GABA decreased EPSCs evoked by optic nerve stimulation in bicuculline or picrotoxin treated slices
Farajnia et al. (2014) PMID 24979761	8:16 12:12 16:8	Fura-2 Ca²⁺imaging	Slice preparation; PD56– 112 mice	GABA (focal application)	In LD 16:8 GABA increased Ca²⁺in 40% of neurons and decreased Ca²⁺in 36%; in LD 12:12 GABA increased Ca²⁺ in 32% and decreased Ca²⁺in 43%; in LD 8:16 GABA increased Ca²⁺in 28% of neurons and decreased Ca²⁺in 52%; no differences were observed between ventral and dorsal SCN

Notes: LD cycle refers to animal housing prior to tissue preparation; day and night refer to subjective day and night; whole cell voltage clamp recordings clamp the intracellular chloride concentrations making determination of the nature (excitatory or inhibitory) of spontaneous synaptic events difficult. Postnatal day (PD), embryonic day (ED), calcium (Ca²⁺), inhibitory postsynaptic current (IPSC), Pubmed identification number (PMID).