Gabaa antagonist

Bisabolol (α-(-)-bisabolol) is a sesquiterpene which is a part of the essential oil of a variety of plants, but its common source is German chamomile. Several bioactivities including anti-inflammatory, anti-nociceptive, and anti-tumor effects were attributed to bisabolol. However, the neuropharmacological properties of bisabolol have not yet been reported. The present study evaluated behavioral effects of bisabolol using elevated plus maze (EPM), open field test (OFT), and rotarod test. Moreover, this study also examined whether the 5-HT1A and GABAA-benzodiazepine receptor systems are involved in the anxiolytic-like effects of bisabolol...

Riluzole blocks persistent Na(+) current, inhibits generation of neuronal bursts and decreases glutamate-induced excitotoxicity. In previous studies of respiratory activity, riluzole suppressed inspiratory-related burst generation activity in rat slice or en bloc preparations. We examined riluzole's effects on inspiratory burst generation and drug-induced seizure-like activity in newborn rat en bloc preparations. Medulla-spinal cord preparations from postnatal day 0-3 Wistar rats were isolated under deep isoflurane anesthesia and were superfused with artificial cerebrospinal fluid equilibrated with 95% O2 and 5% CO2, pH 7...

Agmatine and GABA have been abundantly expressed in brain nuclei involved in regulation of energy homeostasis and promoting stimulation of food intake in rodents. However, their mutual interaction, if any, in the elicitation of feeding behavior is largely remains unclear. The current study provides experimental evidence for the possible interaction of agmatine, adrenergic and GABAergic systems in stimulation of feeding in satiated rats. Satiated rats fitted with intracerebroventricular (i.c.v.) cannulae and were administered agmatine, alone or jointly with (a) GABAA receptor agonist, muscimol, diazepam or antagonist bicuculline and flumazenil, GABAA positive modulator, allopregnanolone or negative modulator of GABAA receptor, dehydroepiandrosterone (b) In view of the high affinity of agmatine for α2-adrenoceptors and the close association between α2-adrenoceptors and GABAergic system, the effect of their modulators on feeding elicited by agmatine/GABAergic agonists were also examined...

Temporal lobe epilepsy is characterized by recurrent seizures in one or both temporal lobes of the brain; some in vitro models show that epileptiform discharges initiate in entorhinal layer V neurons and then spread into other areas of the temporal lobe. We previously found that, in the presence of GABAA receptor antagonists, stimulation of afferent fibers, terminating both at proximal and distal dendritic locations, initiated hyperexcitable bursts in layer V medial entorhinal neurons. We investigated the differential contribution of Ca(2+)-dependent mechanisms to the plateaus underlying these bursts at proximal and distal synapses...

Insomnia and circadian rhythm sleep disorders affect large proportions of the population and have pronounced effects on quality of life and daytime performance. While the neurobiology of insomnia is not yet fully understood, circadian rhythm sleep disorders are assumed to be caused by a mismatch between the individual circadian phase position and the desired sleep-wake schedule. Benzodiazepines and non-benzodiazepine positive allosteric GABAA receptor modulators improve sleep onset and maintenance in the short-term treatment of insomnia...

Previous work has shown that S44819 is a novel GABAA receptor (GABAAR) antagonist, which is selective for extrasynaptic GABAARs incorporating the α5 subunit (α5-GABAARs). The present study reports on the preclinical neuropsychopharmacological profile of S44819. Significantly, no sedative or pro-convulsive side effects of S44819 were found at doses up to 30 mg/kg i.p. Object recognition (OR) memory in intact mice was enhanced by S44819 (0.3 mg/kg p.o.) given before the acquisition trial. Mice treated with phencyclidine for two weeks and tested six days after the cessation of treatment failed to show OR memory...

Several neocortical projections converge onto the basolateral complex of the amygdala (BLA), including the lateral orbitofrontal cortex (lOFC) and medial prefrontal cortex (mPFC). Lateral orbitofrontal input to BLA is important for cue-outcome contingencies, while medial prefrontal input is essential for emotion control. In this study, we examined how mPFC, specifically the infralimbic (IL) division of mPFC, modulates the lOFC-BLA information flow, using combined in vivo extracellular single-unit recordings and pharmacological manipulations in anesthetized rats...

Gama amino butyric acid (GABA) inhibition plays an important role in the onset and offset of the critical period for ocular dominance (OD) plasticity in the primary visual cortex. Previous studies have focused on the involvement of GABAA receptors, while the potential contribution of GABAB receptors to OD plasticity has been neglected. In this study, the GABAB receptor antagonist SCH50911 or agonist baclofen was infused into the primary visual cortex of cats concurrently with a period of monocular deprivation (MD)...

Numerous studies in animals and humans have established that oxytocin (OT) reduces anxiety. In rats, the prelimbic (PL) subregion of the medial prefrontal cortex (mPFC) is among the brain areas implicated in the anxiolytic actions of OT. However, questions remain about the anatomical and receptor specificity of OT and its mechanism of action. Here we assessed whether the regulation of anxiety by mPFC OT is restricted to the PL subregion and evaluated whether oxytocin receptor (OTR) activation is required for OT to have an anxiolytic effect...

Down syndrome (DS), a genetic condition due to triplication of Chromosome 21, is characterized by numerous neurodevelopmental alterations and intellectual disability. Individuals with DS and DS mouse models are impaired in several memory domains, including hippocampus-dependent declarative (spatial, in rodents) memory and visual recognition memory, a form of memory in which the perirhinal cortex (PRC) plays a fundamental role. The anatomo-functional substrates of hippocampus-dependent memory impairment have been largely elucidated in the Ts65Dn mouse model of DS...

RATIONALE: Both prefrontal cortex (PFC) GABAA and NMDA transmission regulate attentional processes, yet how they may differentially regulate signal detection or other aspects of attention is unclear. OBJECTIVES: We examined PFC GABAA and NMDA receptor regulation of attention using a sustained attention task (SAT) permitting identification of distinct forms of impairments. As this task requires implementation of conditional rules, we also investigated how reducing PFC GABA transmission affected performance of visual and auditory conditional discriminations...

The aim of the present study was to observe whether dopamine receptor (DR) was involved in the effects of sodium salicylate (SS) on the expressions of N-methyl-D-aspartic acid (NMDA) and γ-aminobutyric acid (GABA) receptors in rat cochlear spiral ganglion neurons (SGNs). Forty-eight hours after primary culture of rat SGNs, immunofluorescence technique was applied to detect expressions of DR1 and DR2, the two subtypes of dopamine receptors. Western blot was performed to assess NMDA receptor NR1 subunit and GABAA receptor subunit α2 (GABRα2) protein expressions in the SGNs after the treatments of SS alone or in combination with DR antagonists...

BACKGROUND: Chronic stress induces an impaired GABAA (γ-aminobutyric acid type A) receptor-mediated inhibition in the hypothalamic paraventricular nucleus (PVN). It is not clear whether GABAB receptor function is altered in chronic stress. We hypothesize that chronic stress alters GABAB receptor function in PVN corticotrophin-releasing hormone (CRH) neurons to control hypothalamus-pituitary-adrenal (HPA) axis activity. EXPERIMENTAL APPROACH: Whole cell patch-clamp recording was performed on PVN-CRH neurons expressing eGFP driven by CRH promoter in brain slices from unstressed rats and rats that had been subjected to chronic unpredictable mild stress (CUMS)...

Experimental exposure to ocean and freshwater acidification affects the behaviour of multiple aquatic organisms in laboratory tests. One proposed cause involves an imbalance in plasma chloride and bicarbonate ion concentrations as a result of acid-base regulation, causing the reversal of ionic fluxes through GABAA receptors, which leads to altered neuronal function. This model is exclusively based on differential effects of the GABAA receptor antagonist gabazine on control animals and those exposed to elevated CO2 However, direct measurements of actual chloride and bicarbonate concentrations in neurons and their extracellular fluids and of GABAA receptor properties in aquatic organisms are largely lacking...

In Huntington's disease (HD), dysfunctional affective processes emerge as key symptoms of disturbances. In human HD and transgenic rat models of the disease, the amygdala was previously shown to have a reduced volume and to carry a high load of mutant huntingtin (mHTT) aggregates. In search of the pathophysiology of affective dysregulation in HD, we hypothesized a specific role of the central amygdala (CeA), known to be particularly involved in emotional regulation. Using transgenic BACHD rats carrying full-length human mHTT, we compared behavioral consequences of pharmacological modulation of CeA function by infusing GABAA receptor (GABAAR) antagonist picrotoxin into ∼4...

The bed nucleus of the stria terminalis (BST) consists of multiple anatomically distinct nuclei. The lateral division, which receives dense noradrenergic innervation, has been implicated in cardiovascular regulation and modulation of responses to stress. This study is performed to identify the cardiovascular and single-unit responses of the lateral BST to norepinephrine (NE), involved adrenoceptors, and possible interaction with GABAergic system of the BST in urethane-anesthetized rats. NE, adrenoreceptor antagonists, and GABAA antagonist were microinjected into the lateral division of BST, while arterial pressure (AP), heart rate (HR), and single-unit responses were simultaneously recorded...

OBJECTIVE: Mutations of the KCNQ2 gene, which encodes the Kv 7.2 subunit of voltage-gated M-type potassium channels, have been associated with epilepsy in the neonatal period. This developmental stage is unique in that the neurotransmitter gamma aminobutyric acid (GABA), which is inhibitory in adults, triggers excitatory action due to a reversed chloride gradient. METHODS: To examine whether KCNQ2-related neuronal hyperexcitability involves neonatally excitatory GABA, we examined 1-week-old knockin mice expressing the Kv 7...

Swietenia humilis Zucc. (Meliaceae) seeds are used in Mexico for the treatment of type 2 diabetes mellitus. Mexicanolides are the main hypoglycemic and antihyperglycemic compounds of the species. This study was conducted to investigate the antihyperalgesic effect of an aqueous extract of the seeds of Swietenia humilis (SHAE) and of mexicanolide 2-hydroxy-destigloyl-6-deoxyswietenine acetate (1), using the formalin test in mice. The antihyperalgesic actions of SHAE and mexicanolide 1, as well as its possible transductional activity, were assessed in nicotinamide-streptozotocin (NA-STZ) hyperglycemic mice...

PURPOSE: The zona incerta (ZI) is below the ventral tier of the thalamus and has a strong influence selectively in higher-order thalamic relays. Although neuropathic pain has been suggested to result from reduced gamma-aminobutyric acid (GABA) and GABAergic signaling in the ZI, the mechanisms remain unclear. Here, the role of GABA and GABAergic signaling was investigated in the ZI in neuropathic pain using sciatic nerve chronic constriction injury (CCI) rats. MATERIALS AND METHODS: Single-unit neuronal activity was recorded, and microdialysis was performed in the ZI of CCI rats and sham-treated rats in vivo...

Alpha-7 nicotinic acetylcholine receptor (α7-nAChR) agonists can prevent glutamate-induced excitotoxicity in cultured retinal ganglion cells (RGCs). However, the neuroprotective effects and the mechanism of action of PNU-282987, an α7-nAChR agonist, in a chronic in vivo rat glaucoma model are poorly understood. We found that elevated intraocular pressure (IOP) downregulated retinal α7-nAChR expression. Electroretinography revealed that the amplitude of the photopic negative response (PhNR) decreased in parallel with the loss of RGCs caused by elevated IOP...