scholarly journals Development of hyperpolarizing inhibitory postsynaptic potentials and hyperpolarizing response to gamma-aminobutyric acid in rabbit hippocampus studied in vitro

1984 ◽  
Vol 4 (3) ◽  
pp. 860-867 ◽  
Author(s):  
AL Mueller ◽  
JS Taube ◽  
PA Schwartzkroin
Keyword(s):  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Postsynaptic Potentials ◽  
Rabbit Hippocampus ◽  
Inhibitory Postsynaptic Potentials ◽  
Hyperpolarizing Response

scholarly journals Heterogeneity in Use-Dependent Depression of Inhibitory Postsynaptic Potentials in the Rat Neostriatum In Vitro

1997 ◽  
Vol 77 (1) ◽  
pp. 427-434 ◽  
Author(s):  
Gabriele Radnikow ◽  
Jutta Rohrbacher ◽  
Ulrich Misgeld
Keyword(s):  
Aminobutyric Acid ◽  
Medium Spiny Neurons ◽  
Stimulus Interval ◽  
Postsynaptic Potentials ◽  
Inhibitory Postsynaptic Potentials ◽  
Spiny Neurons ◽  
Neostriatal Slices ◽  
Minimal Stimulation ◽  
Paired Pulse Depression

Radnikow, Gabriele, Jutta Rohrbacher, and Ulrich Misgeld. Heterogeneity in use-dependent depression of inhibitory postsynaptic potentials in the rat neostriatum in vitro. J. Neurophysiol. 77: 427–434, 1997. “Minimal stimulation” was applied to evoke responses in an “all-or-none” fashion in presumed medium spiny neurons of rat neostriatal slices in the presence of antagonists for glutamatergic excitation. For comparison, responses were evoked in the same cells by compound stimulation. Bicuculline (30 μM) blocked responses evoked by minimal stimulation, indicating that they were γ-aminobutyric acid-A (GABAA)-receptor-mediated inhibitory postsynaptic potentials (IPSPs), whereas responses evoked by compound stimulation were only reduced in amplitude. Likewise, R(−)baclofen (1–20 μM) blocked IPSPs evoked by minimal stimulation in all but one cell. On the contrary, responses evoked by compound stimulation were always reduced in amplitude but never blocked. Paired-pulse depression (PPD) of averaged responses to minimal and compound stimulation was observed at a stimulus interval of 300 ms. The GABAB receptor antagonist CGP55845A (0.5 μM) had no effect on PPD evoked by compound stimulation but abolished PPD evoked by minimal stimulation. In a second set of experiments, the two stimulation paradigms were used to evoke responses in neostriatal slices continuously bathed in R(−)baclofen (10–20 μM). In R(−)baclofen a strong PPD was evoked by minimal and by compound stimulation. The amplitude of the response to compound stimulation increased on application of CGP55845A (0.5 μM). At the same time, PPD evoked by compound stimulation decreased. On the contrary, IPSP amplitude and PPD evoked by minimal stimulation remained unchanged. We conclude that two types of GABAergic terminals exist in the rat neostriatum, only one of which is regulated by GABAB receptors. However, the other class of terminals, not regulated by GABAB receptors, displays a much more pronounced PPD.

scholarly journals Inositol incorporation into phosphoinositides in retinal horizontal cells of Xenopus laevis: enhancement by acetylcholine, inhibition by glycine.

1984 ◽  
Vol 99 (2) ◽  
pp. 686-691 ◽  
Author(s):  
R E Anderson ◽  
J G Hollyfield
Keyword(s):  
Xenopus Laevis ◽  
Culture Medium ◽  
Photoreceptor Cells ◽  
Horizontal Cells ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Light Effect ◽  
Synaptic Inputs ◽  
Absorption Of Light

The absorption of light by photoreceptor cells leads to an increased incorporation of [2-3H]inositol into phosphoinositides of horizontal cells in the retina of Xenopus laevis in vitro. We have identified several retinal neurotransmitters that are involved in regulating this response. Incubation with glycine, the neurotransmitter of an interplexiform cell that has direct synaptic input onto horizontal cells, abolishes the light effect. This inhibition is reversed by preincubation with strychnine. Acetylcholine added to the culture medium enhances the incorporation of [2-3H]inositol into phosphoinositides in horizontal cells when retinas are incubated in the dark. This effect is inhibited by preincubation with atropine. However, atropine alone does not inhibit the light-enhanced incorporation of [2-3H]inositol into phosphoinositides in the retina. gamma-Aminobutyric acid, the neurotransmitter of retinal horizontal cells in X. laevis, as well as dopamine and norepinephrine, have no effect on the incorporation of [2-3H]inositol into phosphoinositides. These studies demonstrate that the light-enhanced incorporation of [2-3H]inositol into phosphoinositides of retinal horizontal cells is regulated by specific neurotransmitters, and that there are probably several synaptic inputs into horizontal cells which control this process.

Effect of exposure in vitro to ethanol and hypoxia on gamma-aminobutyric acid efflux in the hippocampus of the fetal and adult guinea-pig

1995 ◽  
Vol 7 (5) ◽  
pp. 1339 ◽  
Author(s):  
MC Catlin ◽  
DH Penning ◽  
JF Brien
Keyword(s):  
Guinea Pig ◽  
Hippocampal Slices ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Gaba System ◽  
Direct Exposure ◽  
Interface System ◽  
Near Term ◽  
Co2 Environment

The objective of this study was to determine the effects of acute direct exposure to ethanol, hypoxia or ethanol plus hypoxia on K+-stimulated gamma-aminobutyric acid (GABA) efflux (neuronal release minus uptake) in the hippocampus of the near-term fetal and adult guinea-pig. Transverse hippocampal slices were studied in a static-interface system. Exposure in vitro to ethanol or hypoxia involved 10-min incubation with 50 mM ethanol or 10-min incubation in a 95% N2/5% CO2 environment. GABA was quantitated by HPLC. Ethanol did not alter K+-stimulated GABA efflux; hypoxia augmented K+-stimulated GABA efflux three-fold in the near-term fetus and seven-fold in the adult; concurrent exposure to ethanol did not alter the effect of hypoxia. The data demonstrate that, for acute direct exposure to hypoxia and/or ethanol, only hypoxia increases K+-stimulated GABA efflux, the magnitude of which is dependent on the extent of development of the GABA system.

Leptin inhibits norepinephrine efflux from the hypothalamus in vitro: role of gamma aminobutyric acid

2004 ◽  
Vol 1021 (2) ◽  
pp. 286-291 ◽  
Author(s):  
Joseph Francis ◽  
Sheba M.J. MohanKumar ◽  
P.S. MohanKumar
Keyword(s):  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid

scholarly journals In Vitro Capacitating Effect of Gamma-Aminobutyric Acid in Ram Spermatozoa1

1997 ◽  
Vol 56 (4) ◽  
pp. 964-968 ◽  
Author(s):  
Marcelo A. de las Heras ◽  
Alberto Valcarcel ◽  
Leandro J. Perez
Keyword(s):  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid
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