scholarly journals Axonal Modulation of Striatal Dopamine Release by Local γ-Aminobutyric Acid (GABA) Signalling

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 709
Author(s):  
Bradley M. Roberts ◽  
Emanuel F. Lopes ◽  
Stephanie J. Cragg
Keyword(s):  
Gabab Receptors ◽  
Striatal Dopamine ◽  
Aminobutyric Acid ◽  
Gaba Uptake ◽  
Short Term Plasticity ◽  
Psychomotor Disorders ◽  
Gabaa And Gabab Receptors ◽  
Uptake Transporters ◽  
Gabaergic Modulation ◽  
Da Release

Striatal dopamine (DA) release is critical for motivated actions and reinforcement learning, and is locally influenced at the level of DA axons by other striatal neurotransmitters. Here, we review a wealth of historical and more recently refined evidence indicating that DA output is inhibited by striatal γ-aminobutyric acid (GABA) acting via GABAA and GABAB receptors. We review evidence supporting the localisation of GABAA and GABAB receptors to DA axons, as well as the identity of the striatal sources of GABA that likely contribute to GABAergic modulation of DA release. We discuss emerging data outlining the mechanisms through which GABAA and GABAB receptors inhibit the amplitude as well as modulate the short-term plasticity of DA release. Furthermore, we highlight recent data showing that DA release is governed by plasma membrane GABA uptake transporters on striatal astrocytes, which determine ambient striatal GABA tone and, by extension, the tonic inhibition of DA release. Finally, we discuss how the regulation of striatal GABA-DA interactions represents an axis for dysfunction in psychomotor disorders associated with dysregulated DA signalling, including Parkinson’s disease, and could be a novel therapeutic target for drugs to modify striatal DA output.

scholarly journals Gamma-Aminobutyric Acid (GABA) Inhibits α-Melanocyte-Stimulating Hormone-Induced Melanogenesis through GABAA and GABAB Receptors

2021 ◽  
Vol 22 (15) ◽  
pp. 8257
Author(s):  
Ilandarage Menu Neelaka Molagoda ◽  
Mirissa Hewage Dumindu Kavinda ◽  
Hyung Won Ryu ◽  
Yung Hyun Choi ◽  
Jin-Woo Jeong ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Melanoma Cells ◽  
Gabab Receptors ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
B16f10 Melanoma ◽  
Melanocyte Stimulating Hormone ◽  
Zebrafish Larvae ◽  
B16f10 Melanoma Cells ◽  
Gabaa And Gabab Receptors

Gamma-aminobutyric acid (GABA) is considered the primary inhibitory neurotransmitter in the human cortex. However, whether GABA regulates melanogenesis has not been comprehensively elucidated. In this study, we reveal that GABA (20 mM) significantly inhibited α-melanocyte-stimulating hormone (α-MSH)-induced extracellular (from 354.9% ± 28.4% to 126.5% ± 16.0%) and intracellular melanin contents (from 236.7% ± 11.1% to 102.7% ± 23.1%) in B16F10 melanoma cells, without inducing cytotoxicity. In addition, α-MSH-induced hyperpigmentation in zebrafish larvae was inhibited from 246.3% ± 5.4% to 116.3% ± 3.1% at 40 mM GABA, displaying no apparent cardiotoxicity. We also clarify that the GABA-mediated antimelanogenic properties were related to the direct inhibition of microphthalmia-associated transcription factor (MITF) and tyrosinase expression by inhibiting cyclic adenosine monophosphate (cAMP) and cAMP response element-binding protein (CREB). Furthermore, under α-MSH stimulation, GABA-related antimelanogenic effects were mediated through the GABAA and GABAB receptors, with subsequent inhibition of Ca2+ accumulation. In B16F10 melanoma cells and zebrafish larvae, pretreatment with bicuculline, a GABAA receptor antagonist, and CGP 46381, a GABAB receptor antagonist, reversed the antimelanogenic effect of GABA following α-MSH treatment by upregulating Ca2+ accumulation. In conclusion, our results indicate that GABA inhibits α-MSH-induced melanogenesis. Hence, in addition to the health benefits of GABA in the central nervous system, it could ameliorate hyperpigmentation disorders.

scholarly journals GABA uptake transporters support dopamine release in dorsal striatum with maladaptive downregulation in a parkinsonism model

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Bradley M. Roberts ◽  
Natalie M. Doig ◽  
Katherine R. Brimblecombe ◽  
Emanuel F. Lopes ◽  
Ruth E. Siddorn ◽  
...  
Keyword(s):  
Dorsal Striatum ◽  
Gaba Uptake ◽  
Projection Neurons ◽  
Nucleus Accumbens Core ◽  
Dorsolateral Striatum ◽  
Striatal Projection Neurons ◽  
Maladaptive Plasticity ◽  
Uptake Transporters ◽  
Da Release ◽  
Accumbens Core

Abstract Striatal dopamine (DA) is critical for action and learning. Recent data show that DA release is under tonic inhibition by striatal GABA. Ambient striatal GABA tone on striatal projection neurons can be determined by plasma membrane GABA uptake transporters (GATs) located on astrocytes and neurons. However, whether striatal GATs and astrocytes determine DA output are unknown. We reveal that DA release in mouse dorsolateral striatum, but not nucleus accumbens core, is governed by GAT-1 and GAT-3. These GATs are partly localized to astrocytes, and are enriched in dorsolateral striatum compared to accumbens core. In a mouse model of early parkinsonism, GATs are downregulated, tonic GABAergic inhibition of DA release augmented, and nigrostriatal GABA co-release attenuated. These data define previously unappreciated and important roles for GATs and astrocytes in supporting DA release in striatum, and reveal a maladaptive plasticity in early parkinsonism that impairs DA output in vulnerable striatal regions.

scholarly journals Gamma-Aminobutyric Acid (GABA) Promotes Growth in Zebrafish Larvae by Inducing IGF-1 Expression via GABAA and GABAB Receptors

2021 ◽  
Vol 22 (20) ◽  
pp. 11254
Author(s):  
Athapaththu Mudiyanselage Gihan Kavinda Athapaththu ◽  
Ilandarage Menu Neelaka Molagoda ◽  
Rajapaksha Gedara Prasad Tharanga Jayasooriya ◽  
Yung Hyun Choi ◽  
You-Jin Jeon ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Rate ◽  
Growth Performance ◽  
Total Body Length ◽  
Gabab Receptors ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Zebrafish Larvae ◽  
Gabaa And Gabab Receptors ◽  
Total Body

Insulin-like growth factor-1 (IGF-1) primarily increases the release of gamma-aminobutyric acid (GABA) in neurons; moreover, it is responsible for the promotion of longitudinal growth in children and adolescents. Therefore, in this study, we investigated whether exogenous GABA supplementation activates IGF-mediated growth performance. Zebrafish larvae treated with GABA at three days post fertilization (dpf) showed a significant increase in the total body length from 6 to 12 dpf through upregulation of growth-stimulating genes, including IGF-1, growth hormone-1 (GH-1), growth hormone receptor-1 (GHR-1), and cholecystokinin A (CCKA). In particular, at 9 dpf, GABA increased total body length from 3.60 ± 0.02 to 3.79 ± 0.03, 3.89 ± 0.02, and 3.92 ± 0.04 mm at concentrations of 6.25, 12.5, and 25 mM, and the effect of GABA at 25 mM was comparable to 4 mM β-glycerophosphate (GP)-treated larvae (3.98 ± 0.02 mm). Additionally, the highest concentration of GABA (50 mM) -induced death in 50% zebrafish larvae at 12 dpf. GABA also enhanced IGF-1 expression and secretion in preosteoblast MC3T3-E1 cells, concomitant with high levels of the IGF-1 receptor gene (IGF-1R). In zebrafish larvae, the GABA-induced growth rate was remarkably decreased in the presence of an IGF-1R inhibitor, picropodophyllin (PPP), which indicates that GABA-induced IGF-1 enhances growth rate via IGF-1R. Furthermore, we investigated the effect of GABA receptors on growth performance along with IGF-1 activation. Inhibitors of GABAA and GABAB receptors, namely bicuculline and CGP 46381, respectively, considerably inhibited GABA-induced growth rate in zebrafish larvae accompanied by a marked decrease in the expression of growth-stimulating genes, including IGF-1, GH-1, GHR-1, and CCKA, but not with an inhibitor of GABAC receptor, TPMPA. Additionally, IGF-1 and IGF-1R expression was impaired in bicuculline and CGP 46381-treated MC3T3-E1 cells, but not in the cells treated with TPMPA. Furthermore, treatment with bicuculline and CGP 46381 significantly downregulated GABA-induced IGF-1 release in MC3T3-E1 cells. These data indicate that GABA stimulates IGF-1 release via GABAA and GABAB receptors and leads to growth promotion performance via IGF-1R.

scholarly journals Design, Synthesis and Enhanced BBB Penetration Studies of L-serine-Tethered Nipecotic Acid-Prodrug

Drug Research ◽  
2020 ◽  
Author(s):  
Meenakshi Dhanawat ◽  
Sumeet Gupta ◽  
Dinesh Kumar Mehta ◽  
Rina Das
Keyword(s):  
Epileptic Activity ◽  
Aminobutyric Acid ◽  
Gaba Uptake ◽  
Nipecotic Acid ◽  
Design Synthesis ◽  
Hydrophilic Nature ◽  
Carrier Mediated Transport ◽  
Ester Prodrug ◽  
Hplc Data

Nipecotic acid is considered to be one of the most potent inhibitors of neuronal and glial-aminobutyric acid (GABA) uptake in vitro. Due to its hydrophilic nature, nipecotic acid does not readily cross the blood-brain barrier (BBB). Large neutral amino acids (LAT1)-knotted nipecotic acid prodrug was designed and synthesized with the aim to enhance the BBB permeation by the use of carrier-mediated transport. The synthesized prodrug was tested in animal models of Pentylenetetrazole (PTZ)-induced convulsions in mice. Further pain studies were carried out followed by neurotoxicity estimation by writhing and rota-rod test respectively. HPLC data suggests that the synthesized prodrug has improved penetration through BBB. Nipecotic acid-L-serine ester prodrug with considerable anti-epileptic activity, and the ability to permeate the BBB has been successfully synthesized. Graphical Abstract.

scholarly journals Inhibition of Nigrostriatal Dopamine Release by Striatal GABAA and GABAB Receptors

2018 ◽  
Vol 39 (6) ◽  
pp. 1058-1065 ◽  
Author(s):  
Emanuel F. Lopes ◽  
Bradley M. Roberts ◽  
Ruth E. Siddorn ◽  
Michael A. Clements ◽  
Stephanie J. Cragg
Keyword(s):  
Dopamine Release ◽  
Gabab Receptors ◽  
Nigrostriatal Dopamine ◽  
Gabaa And Gabab Receptors

Systemic CI-966, a new γ-aminobutyric acid uptake blocker, enhances γ-aminobutyric acid action in CA1 pyramidal layer in situ

1990 ◽  
Vol 68 (9) ◽  
pp. 1194-1199 ◽  
Author(s):  
U. Ebert ◽  
K. Krnjević
Keyword(s):  
Aminobutyric Acid ◽  
Gaba Uptake ◽  
Acid Uptake ◽  
Sprague Dawley ◽  
Nipecotic Acid ◽  
Ca1 Region ◽  
Stratum Pyramidale ◽  
Sprague Dawley Rats ◽  
Pyramidal Layer ◽  
Urethane Anaesthesia

A new potent, blood–brain barrier permeable γ-aminobutyric acid (GABA) uptake blocker, 1-[2-[bis[4-(trifluoromethyl)-phenyl]methoxy]ethyl]-1,2,5,6-tetrahydro-3-pyridinecarboxylic acid (CI-966) was administered systemically by i.p. injection (5 mg/kg) in Sprague–Dawley rats under urethane anaesthesia. Twenty to thirty minutes after injection there was a highly variable, but overall significant, enhancement of the inhibition of hippocampal population spikes by GABA applied by microiontophoresis in the CA1 region. Like the effect of nipecotic acid (applied locally by iontophoresis), the potentiation by CI-966 was clearest when GABA was applied in or near the stratum pyramidale where its action normally is weakest and shows the most pronounced fading. This change in GABA potency is most simply explained by a reduction in GABA uptake.Key words: GABA, muscimol, nipecotic acid, GABA-uptake blocker, epilepsy.

Effects of the GABA uptake inhibitor tiagabine on inhibitory synaptic potentials in rat hippocampal slice cultures

1992 ◽  
Vol 67 (6) ◽  
pp. 1698-1701 ◽  
Author(s):  
S. M. Thompson ◽  
B. H. Gahwiler
Keyword(s):  
Time Constant ◽  
Decay Time ◽  
Time Course ◽  
Hippocampal Slice ◽  
Decay Time Constant ◽  
Gabab Receptors ◽  
Gaba Uptake ◽  
Whole Cell ◽  
Synaptic Potentials ◽  
Hippocampal Slice Cultures

1. The effects of the gamma-aminobutyric acid (GABA) uptake blocker tiagabine on inhibitory synaptic potentials (IPSPs) were examined with microelectrode and whole-cell recording from CA3 pyramidal cells in rat hippocampal slice cultures. 2. Tiagabine (10-25 microM) greatly prolonged the duration of monosynaptic IPSPs elicited in the presence of excitatory amino acid antagonists but had no effect on their amplitude. Part of the prolonged time course resulted from a GABAB receptor-mediated component that was not detectable under control conditions. 3. The mean decay time constant of the underlying GABAA receptor-mediated synaptic current was increased from 16 to 250 ms. Spontaneous miniature IPSPs recorded with whole-cell clamp were unaffected by tiagabine. Pentobarbital sodium, in contrast, increased the decay time constant of both evoked and spontaneous GABAA-mediated currents. 4. Tiagabine (25 microM) inhibited spontaneous and evoked epileptiform bursting induced by increasing the extracellular potassium concentration to 8 mM. 5. We conclude that GABA uptake plays a significant role in determining the time course of evoked IPSPs and also limits the likelihood that GABAB receptors are activated.

scholarly journals Role of γ-aminobutyric acid B (GABAB) receptors in the regulation of kainic acid-induced cell death in mouse hippocampus

2005 ◽  
Vol 37 (6) ◽  
pp. 533-545 ◽  
Author(s):  
Han-Kyu Lee ◽  
Young-Jun Seo ◽  
Seong-Soo Choi ◽  
Min-Soo Kwon ◽  
Eon-Jeong Shim ◽  
...  
Keyword(s):  
Cell Death ◽  
Kainic Acid ◽  
Gabab Receptors ◽  
Aminobutyric Acid ◽  
Mouse Hippocampus
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