Search results for "Prague"
showing 10 items of 652 documents
Locomotor and antidepressant-like effects of 5-HT(1A) agonist LY 228729 in prenatally benzodiazepine-exposed rats.
1998
Locomotor activity and antidepressant-like effect in the forced swim test (FST) of 5-HT(1A) agonist LY 228729 were investigated in adult rats prenatally exposed at doses of diazepam (DZ) and alprazolam (ALP) which induce persistent downregulation of GABA/ benzodiazepine (BZ) receptors. Prenatal exposure to ALP and DZ did not modify the efficacy of subchronic LY 228729 to decrease immobility time in the FST. Prenatal DZ and ALP potentiated the facilitatory effect of subchronic LY 228729 on locomotor activity; prenatal DZ was more effective than prenatal ALP. Moreover, prenatal DZ increased stereotypic movements induced by LY 228729. These data suggest that the persistent downregulation of GA…
New dopamine D2 receptor polymorphisms in rats and association with apomorphine-induced stereotypies.
2002
Adult Wistar rats injected with the dopamine receptor agonist apomorphine display different types of motility patterns with respect to oral stereotypes and locomotor activities. It was tested whether phenotypes exhibiting either ‘sniffing’ or ‘non-sniffing’ behaviour differed in gene structures of dopamine receptors D1 or D2. Forty-five Wistar rats of both genders were tested after a single dose of apomorphine (2 mg/kg s.c.) for stereotyped behaviour. Sequence analysis of the 5′ flanking region, the 5′ untranslated region and the coding region of the two genes revealed a new sequence for the 5′ flanking region of the D1 receptor gene and two polymorphisms in the promoter region of the D2 re…
m-Chlorophenylpiperazine excites non-dopaminergic neurons in the rat Substantia Nigra and Ventral Tegmental Area by activating serotonin-2c receptors
2001
In vivo electrophysiological techniques were used to study the effect of m-chlorophenylpiperazine, a non-selective serotonin-2C receptor agonist, on the activity of non-dopaminergic neurons in the substantia nigra pars reticulata and the ventral tegmental area of anesthetized rats. Intravenous administration of m-chlorophenylpiperazine (5–320 μg/kg) caused a dose-dependent increase in the basal firing rate of a subpopulation of nigral neurons which do not respond to a footpinch stimulus [P(0) neurons], whereas it did not affect the activity of neurons which are responsive to the footpinch [P(+) neurons]. However, m-chlorophenylpiperazine (5–320 μg/kg) excited all non-dopaminergic neurons sa…
Biochemical evidence that the atypical antipsychotic drugs clozapine and risperidone block 5-HT(2C) receptors in vivo.
2002
Clozapine and risperidone are two atypical antipsychotic drugs which bind, among other receptors, to 5-HT(2C) receptor subtypes. They inhibit the basal inositol phosphate production in mammalian cells expressing rat or human 5-HT(2C) receptors. This biochemical effect is indicative of inverse agonist activity at these receptors. There is evidence that 5-HT(2C) receptors are involved in the control of the activity of central dopaminergic system. Therefore, the effects of clozapine (5 mg/kg ip), risperidone (0.08 mg/kg ip) and of the typical antipsychotic haloperidol (0.1 mg/kg ip) were studied on the extracellular concentration of dopamine (DA) in the nucleus accumbens of chloral hydrate-ane…
Choline is a Selective Agonist of α7 Nicotinic Acetylcholine Receptors in the Rat Brain Neurons
1998
In the present study, we demonstrate that choline, a precursor of acetylcholine (ACh) and a product of acetylcholine hydrolysis by acetylcholinesterase (AChE), acts as an efficient and relatively selective agonist of alpha7-containing nicotinic acetylcholine receptors (nAChR) in neurons cultured from the rat hippocampus, olfactory bulb and thalamus as well as in PC12 cells. Choline was able to activate postsynaptic and presynaptic alpha7 nAChRs, with the latter action resulting in the release of other neurotransmitters. Although choline was approximately one order of magnitude less potent than ACh (EC50 of 1.6 mM for choline and 0.13 mM for ACh), it acted as a full agonist at alpha7 nAChRs.…
Activation of phospholipases C and D by the novel metabotropic glutamate receptor agonist tADA.
1997
Abstract In hippocampal slices taken from 8-day-old rats, trans-azetidine-2,4-dicarboxylic acid (tADA), a novel glutamatergic agonist acting preferentially at class I mGluR receptors, activates phosphoinositide and phosphatidylcholine hydrolysis with widely different potencies. Inositol phosphate formation was maximally increased at 10 μM tADA ( ec 50: 1.2 μM), while phospholipase D activation was observed at a tADA concentration of 1 mM. This is the first report of a tADA-induced phospholipase D activity. © 1997 Elsevier Science Ltd. All rights reserved.
The nicotinic acetylcholine receptor agonist ABT-594 increases FGF-2 expression in various rat brain regions
2000
The present experiments were designed to extend previous work showing that acute intermittent (-)nicotine treatment upregulates the level of fibroblast growth factor-2 (FGF2) mRNA in several rat brain regions, by the use of the nicotinic acetylcholine receptor (nAChR) agonist ABT-594 with preferential selectivity for the alpha4beta2 nAChR subtype. ABT594 treatment led to a well-defined temporal and regional upregulation of FGF-2 mRNA. A double labelling analysis showed that the up-regulation of FGF-2 mRNA involves both neuronal and non-neuronal cells. The effects of ABT-594 on FGF-2 expression were antagonized by the preferential alpha4beta2 antagonist dihydrobetaerythroidine (DHbetaE), but…
Fibroblast Growth Factor Receptor 1– 5-Hydroxytryptamine 1A Heteroreceptor Complexes and Their Enhancement of Hippocampal Plasticity
2011
Background The hippocampus and its 5-hydroxytryptamine transmission plays an important role in depression related to its involvement in limbic circuit plasticity. Methods The analysis was made with bioluminescence resonance energy transfer, co-immunoprecipitation, in situ proximity ligation assay, binding assay, in cell western and the forced swim test. Results Using bioluminescence resonance energy transfer analysis, fibroblast growth factor receptor 1 (FGFR1)-5-hydroxytryptamine 1A (5-HT1A) receptor complexes have been demonstrated and their specificity and agonist modulation characterized. Their presence based on co-immunoprecipitation and proximity ligation assay has also been indicated…
Functional evidence of inverse agonism in vascular smooth muscle
1996
1. In the present study, depletion of internal Ca2+ stores sensitive to noradrenaline (1 microM) in rat aorta, is the signal for the entry of extracellular Ca2+, not only to refill the stores but also, in our experimental conditions, to activate the contractile proteins. This induces an increase in the resting tone that constitutes, the first functional evidence of this Ca2+ entry. 2. The fact that methoxamine (100 microM) reproduces the same processes as noradrenaline but clonidine (1 microM) does not, indicates that alpha(1)-adrenoceptor activation is related to the increase in the resting tone observed after depletion of adrenoceptor-sensitive internal Ca2+-stores. 3. Benoxathian and WB …
Erythrocytes labeled with [18F]SFB as an alternative to radioactive CO for quantification of blood volume with PET
2013
Inhaled radioactive CO is currently the tracer of choice for blood volume quantification by positron emission tomography (PET). This measurement is of great interest for several clinical and research applications. However, owing to the short half-life of the radiolabeled CO, it can only be used in centers equipped with a cyclotron. In the present work, we propose an alternative method to label the red blood cells with [(18) F] in order to obtain blood volume measurements by PET. The use of the radioactive synthon [(18) F] N-succinimidyl 4-[(18) F]fluorobenzoate ([(18) F]SFB) was evaluated for erythrocyte labeling and PET blood volume imaging. The images provided by [(18) F]SFB labeled eryth…