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Increased vasopressin transmission from the paraventricular nucleus to the rostral medulla augments cardiorespiratory outflow in chronic intermittent hypoxia-conditioned rats.

A co-morbidity of sleep apnoea is hypertension associated with elevated sympathetic nerve activity (SNA) which may result from conditioning … ted and vagotomized rats. The PVN was disinhibited by microinjecting a GABA(A) receptor antagonist, bicuculline (BIC, 0.1 nmol), before and after blocking V(1A) receptors within the RVLM and rVRC with SR49059 (0.2 nmol). In RA-conditioned rats, disinhibition of the PVN increased BP, HR, minute D(EMG) and GG(EMG) activity and these increases were attenuated af …

Propofol potentiates the depressant effect of alfentanil in isolated neonatal rat spinal cord and blocks naloxone-precipitated hyperresponsiveness.

Our previous studies have shown that a benzodiazepine potentiates opioid actions on spinal cord by blocking a hyperresponsiveness that may be related to the development of opioid tolerance and withdrawal. The present study was designed to test whether propofol, which like benzodiazepines acts on GABA(A) receptors, displays similar interactions with opioids. Spinal cords isolated from 1-7 day old rats were arranged to record the slow ventral root potential (sVRP) elicited by stimulating a lumbar dorsal root. A concentration of propofol which by itself did not depress sVRP significantly enhanced

Functional heterogeneity of the matrix compartment in the cat caudate nucleus as demonstrated by the cholinergic presynaptic regulation of dopamine release.

Previously, using a new in vitro microsuperfusion procedure, we have demonstrated marked differences in the cholinergic presynaptic regulati … effect on [3H]dopamine release was transformed into a long stimulatory response in the presence of bicuculline (50 microM) but not naloxone (1 microM) in matrix 2 while the reverse was observed in matrix 1. By providing further evidence for a functional heterogeneity of the matrix, our results suggest that depending on the matrix area investigated, dynorphin …

The effect of beta-sitosterol and its derivatives on depression by the modification of 5-HT, DA and GABA-ergic systems in mice.

Beta-sitosterol belongs to the group of phytosterols, which are active trace components existing in natural plants, known as the "key of lif … depressant-like effect of Sit-S showed that agomelatine (40 mg kg-1), haloperidol (0.2 mg kg-1) and bicuculline (4 mg kg-1) reversed the antidepressant effect of Sit-S (4 mg kg-1). This study confirmed the conclusions that beta-sitosterol derivatives broaden the pharmacological effects of beta-sitosterol, Sit-S (4 mg kg-1) exhibits antidepressant-like effects …

Physical Exercise Modulates L-DOPA-Regulated Molecular Pathways in the MPTP Mouse Model of Parkinson's Disease.

Parkinson's disease (PD) is characterized by the degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc), res … ated signaling cascades that are regulated by the top upstream regulators L-DOPA, RICTOR, CREB1, or bicuculline/dalfampridine, associated with movement disorders, mitochondrial dysfunction, and epilepsy-related processes. To elucidate the molecular pathways underlying these cascades, we integrated the proteins encoded by the exercise-induced differentially ex …

Anxiolytic- and antidepressant-like activities of a methanolic extract of Morinda citrifolia Linn. (noni) fruit in mice: Involvement of benzodiazepine-GABAAergic, serotonergic and adrenergic systems.

This study presents anxiolytic- and antidepressant-like effects of a methanolic extract of Morinda citrifolia Linn. (noni) fruit (MMC) in well-established mouse models of anxiety and depression. The administration of MMC (1 g/kg, p.o.) and diazepam (1 mg/kg, i.p.) significantly attenuated anxiety-like behaviour in mice by increasing the percentage of time spent and number of entries in the open arms in the elevated plus maze (EPM), and significantly enhanced the exploration in the light box in the light/dark test (LDT). The pre-treatment with flumazenil (6 mg/kg, i.p.) or bicuculline (3 mg/kg,…

Nanomolar oxytocin synergizes with weak electrical afferent stimulation to activate the locomotor CpG of the rat spinal cord in vitro.

Synergizing the effect of afferent fibre stimulation with pharmacological interventions is a desirable goal to trigger spinal locomotor acti … timulus and peptide-concentration dependent fashion. Disinhibited bursting caused by strychnine and bicuculline was accelerated by oxytocin whose action was blocked by the oxytocin antagonist atosiban. Fictive locomotion appeared when subthreshold concentrations of NMDA plus 5HT were coapplied with oxytocin, an effect prevented after 24 h incubation with the …

2'-Methoxy-6-methylflavone: a novel anxiolytic and sedative with subtype selective activating and modulating actions at GABA(A) receptors.

BACKGROUND AND PURPOSE: Flavonoids are known to have anxiolytic and sedative effects mediated via actions on ionotropic GABA receptors. We s … eO6MF directly activated the receptors without potentiating GABA. This activation was attenuated by bicuculline and gabazine but not flumazenil indicating a novel site. Mutation studies showed position 265 in the β1/2 subunit was key to whether 2'MeO6MF was an activator or a potentiator. In hippocampal neurons, 2'MeO6MF directly activated single-channel curre …

Opioidergic, GABAergic and serotonergic neurotransmission in the dorsal raphe nucleus modulates tonic immobility in guinea pigs.

Tonic immobility (TI) is an innate defensive behavior that can be elicited by physical restriction and postural inversion and is characteriz … e DRN in TI defensive behavioral responses in guinea pigs. Microinjection of morphine (1.1 nmol) or bicuculline (0.5 nmol) into the DRN increased the duration of TI. The effect of morphine (1.1 nmol) was antagonized by pretreatment with naloxone (0.7 nmol), suggesting that the activation of μ opioid receptors in the DRN facilitates the TI response. By contras …

Differential processing of excitation by GABAergic gain modulation in canine caudal ventral respiratory group neurons.

The discharge frequency (F(n)) patterns of medullary respiratory premotor neurons are subject to potent tonic GABAergic gain modulation. Stu … ic acid (AMPA), was quantified before and during locally induced antagonism of GABA(A) receptors by bicuculline or small-conductance, calcium-activated potassium channels by apamin. The AMPA-induced net increases in F(n) were not significantly altered by BIC, although it produced large increases in the respiratory-related activity. However, the AMPA-induced n …

Local opiate withdrawal in locus coeruleus neurons in vitro.

Noradrenergic neurons of the brain nucleus locus coeruleus (LC) become hyperactive during opiate withdrawal. It has been uncertain to what e … te and GABA antagonists (6-cyano-7-nitroquinoxalene-2,3-dione + 2-amino-5-phosphonopentanoic acid + bicuculline) blocked the hyperactivity of LC neurons precipitated by naloxone in slices from morphine-dependent rats. The effects of ouabain on MP and SDR were similar in LC neurons from control and morphine-dependent rats. These results indicate that an adapti …

A developmental shift from GABAergic to glycinergic transmission in the central auditory system.

GABAergic and glycinergic circuits are found throughout the auditory brainstem, and it is generally assumed that transmitter phenotype is es … n adult animals. GABAergic and glycinergic components were identified by blocking transmission with bicuculline and strychnine (SN), respectively. In the medial limb of LSO, there was a dramatic change in the GABAergic IPSC component, decreasing from 78% at postnatal day 3 (P3)-P5 to 12% at P12-P16. There was an equal and opposite increase in the glycinergic …

Opioid-induced release of neurotensin in the periaqueductal gray matter of freely moving rats.

The midbrain periaqueductal gray matter (PAG) is an important region for endogenous pain suppression. Nerve terminals containing opioid pept … he opioid induced release of NT. However, local administration in the PAG of the GABA(A) antagonist bicuculline (0.1-10 microM) or the GABA(A) agonist muscimol (1-100 microM) had no significant effect on the extracellular NT-LI level in the PAG, suggesting that GABAergic mechanisms are not involved in the opioid-induced release of NT-LI. In conclusion, the pr …

Changes in GABAA receptor function and cross-tolerance to ethanol in diazepam-dependent rats.

Changes in gamma-aminobutyric acidA (GABAA) receptor function and their relation to cross-tolerance to ethanol (EtOH) were studied in diazep … BA-dependent 38Cl- influx was enhanced by FZ in the withdrawn group. The addition of picrotoxin and bicuculline inhibited GABA-dependent 38Cl- influx in each group. The stimulatory effect of FZ on GABA-dependent 38Cl- influx was inhibited by the addition of Ro 15-1788 in the control group. However, such an inhibitory effect was not observed in the withdrawn g …

L-lysine is a barbiturate-like anticonvulsant and modulator of the benzodiazepine receptor.

Our earlier observations showed that L-lysine enhanced the activity of diazepam against seizures induced by pentylenetetrazol (PTZ), and inc … PTZ effect of L-lysine was not blocked by Ro15-1788. Picrotoxinin and the GABA, receptor antagonist bicuculline partially inhibited L-lysine's enhancement of [3H]FTZ binding with the IC50s of 2 microM and 0.1 microM, respectively. The convulsant benzodiazepine Ro5-3663 dose-dependently inhibited the enhancement of [3H]FTZ binding by L-lysine. This article sho …

GABA receptor molecules of insects.

Receptors for 4-aminobutyric acid (GABA) have been identified in both central and peripheral nervous systems of several invertebrate phyla. … dicated that many insect receptors of this type are insensitive to the vertebrate GABAA antagonists bicuculline and pitrazepin. Benzodiazepine binding sites coupled to insect GABA receptors display a pharmacological profile distinct from that of corresponding sites in vertebrate CNS. Receptor binding studies have also demonstrated differences between convulsa …

Different gamma-aminobutyric acid receptor subtypes are involved in the regulation of opiate-dependent and independent luteinizing hormone-releasing hormone secretion.

The neurotransmitter gamma-aminobutyric acid (GABA) appears to be involved in the control of gonadotropin secretion. These studies were cond … inine vasopressin and oxytocin. This stimulatory effect was blocked by the specific GABA antagonist bicuculline, suggesting the involvement of GABA-A type receptors. Muscimol-stimulated LHRH release was not affected by the presence of phentolamine, suggesting that the stimulatory effect of GABA-A receptors on LHRH release is not mediated by interactions with …

Ionic Plasticity: Common Mechanistic Underpinnings of Pathology in Spinal Cord Injury and the Brain.

The neurotransmitter GABA is normally characterized as having an inhibitory effect on neural activity in the adult central nervous system (CNS), which quells over-excitation and limits neural plasticity. Spinal cord injury (SCI) can bring about a modification that weakens the inhibitory effect of GABA in the central gray caudal to injury. This change is linked to the downregulation of the potassium/chloride cotransporter (KCC2) and the consequent rise in intracellular Cl- in the postsynaptic neuron. As the intracellular concentration increases, the inward flow of Cl- through an ionotropic GABA

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… These excitatory effects are blocked by intrathecal application of the GABA-A antagonist bicuculline [ 69 ]. … Blocking this tonic effect with bicuculline removes this brake, inducing a state akin to nociceptive sensitization. …

The lemniscal-cuneate recurrent excitation is suppressed by strychnine and enhanced by GABAA antagonists in the anaesthetized cat.

INTRODUCTION: Acute promyelocytic leukemia (APL) is defined by the PML-RARα fusion gene, which serves as a key biomarker for pathogenesis, diagnosis, and measurable residual disease (MRD) monitoring. The incorporation of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has markedly transformed treatment outcomes. However, treatment-related toxicities frequently lead to treatment interruptions that may lead to persistent MRD post-induction therapy. This study investigates whether variations in doses are associated with persistent MRD. Additionally, statistical modelling is utilized to

Furosemide action on cerebellar GABA(A) receptors in alcohol-sensitive ANT rats.

Furosemide increases the basal tert-[35S]butylbicyclophosphorothionate ([35S]TBPS) binding and reverses the inhibition of the binding by gamma-aminobutyric acid (GABA) in the cerebellar GABA(A) receptors containing the alpha6 and beta2/beta3 subunits. These effects are less pronounced in the alcohol-sensitive (ANT) than in the alcohol-insensitive (AT) rat line. The difference between the rat lines in the increase of basal [35S]TBPS binding was removed after a longer preincubation with ethylendiaminetetraacetic acid (EDTA) containing buffer, but long preincubation did not reduce the GABA conten