Search results for "Transmitter"
showing 10 items of 348 documents
Effects of co-administration of amitriptyline and fluoxetine on inhibitory avoidance in mice
2010
We have previously observed that, while the impairing effects of amitriptyline on inhibitory avoidance in mice are consistently observed, those of acute fluoxetine are negligible. Two experiments were designed to investigate whether a regular dose of fluoxetine potentiates the effect of a low dose of amitriptyline that is ineffective when administered alone. Male and female CD1 mice were administered i.p. 30 min before training, as follows. In the first experiment, they were injected with saline, one of three doses of amitriptyline (2.5, 5, 10 mg/kg), one dose of fluoxetine (15 mg/kg), or a combination of amitriptyline (2.5 mg/kg) and fluoxetine (15 mg/kg). In the second experiment, the mic…
Astroglial plasticity in the hippocampus is affected by chronic psychosocial stress and concomitant fluoxetine treatment.
2006
Analysis of post-mortem tissue from patients with affective disorders has revealed a decreased number of glial cells in several brain areas. Here, we examined whether long-term psychosocial stress influences the number and morphology of hippocampal astrocytes in an animal model with high validity for research on the pathophysiology of major depression. Adult male tree shrews were submitted to 5 weeks of psychosocial stress, after which immunocytochemical and quantitative stereological techniques were used to estimate the total number and somal volume of glial fibrillary acidic protein-positive astrocytes in the hippocampal formation. Stress significantly decreased both the number (-25%) and…
Characterization of the muscarine receptors involved in the modulation of serotonin release from the vascularly perfused small intestine of guinea pi…
1989
Isolated small intestinal segments of the guinea pig were arterially perfused and the release of 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) into the portal venous effluent measured by HPLC with electrochemical detection. Test substances were applied via the arterial perfusion medium. McN-A-343, pilocarpine and oxotremorine inhibited concentration-dependently the outflow of 5-HT and 5-HIAA. Pirenzepine (0.03-0.1 mumol/l) which can discriminate between M1 and M2-receptor subtypes antagonized completely this inhibitory effect. In the presence of 1 mumol/l tetrodotoxin (TTx), all three muscarine receptor agonists increased the outflow of 5-HT and 5-HIAA. O…
Impact of ''off-label'' use of ivabradine on exercise capacity, gas exchange, functional class, quality of life, and neurohormonal modulation in pati…
2010
Background: Epidemiologic studies indicate that elevated heart rate (HR) is an independent risk factor for mortality and morbidity in patients (pts) with chronic heart failure (CHF). Clinical trials with b-blockers suggest that HR reduction is an important mechanism of their benefit in pts with stable CHF. Pharmacologic inhibition of the If current now provides the opportunity of pure HR reduction. The purpose of this study was to evaluate the impact of ‘‘Off-Label’’ use of ivabradine on exercise capacity, gas exchange, functional class, quality of life, and neurohormonal modulation in pts with ischemic CHF. Methods: Between January 2008 and June 2008, a graded maximal exercise test with re…
[3H]-DA release evoked by low pH medium and internal H+ accumulation in rat hypothalamic synaptosomes: involvement of calcium ions
2003
The pH fluctuations have been often interpreted as an insufficient regulation or as a consequence of the onset of pathological events, such as ischemia, in which a significant decrease in pH levels occurs. Neurotransmitter release appears to be affected by pH drop significantly. In this study, we investigated the effect of an extracellular and an intracellular acidification on tritiated dopamine release ([3H]-DA release), from superfused rat hypothalamic synaptosomes. When compared to basal release, extracellular acidification, due to a reduction in the external pH of the nominally carbonic-free superfusion media, provoked a significant increase in [3H]-DA release that showed a sensitivenes…
Evidence for noradrenaline and adrenaline as sympathetic transmitters in the chicken.
1975
1 The concentrations of noradrenaline and adrenaline in various organs, arterial plasma and venous outflow from isolated hearts of adult chickens have been determined. 2 The relative adrenaline concentrations (percentage of the sum of noradrenaline and adrenaline) in the heart (33%), spleen (16%) and brain (26%) were higher than those found in mammalian organs. Chemical sympathectomy by pretreatment with 6-hydroxydopamine caused a decrease of the noradrenaline and adrenaline concentrations in the heart to 20 and 23% and in the spleen to 16 and 29%, respectively. 3 Stimulation of the right sympathetic nerves, infusion of tyramine or infusion of a modified Tyrode solution containing 108mM K+ …
Effects of CGS 10746B on hyperactivity and place preference induced by morphine
2001
The effects of CGS 10746B, a dopamine release inhibitor, on spontaneous locomotor activity, morphine-induced hyperactivity, acquisition of conditioned place paradigm and morphine-induced conditioned place preference (CPP) was evaluated in male mice. In experiment 1, animals treated with CGS 10746B (0.5, 1, 2, 4, 8, 16, 24 and 32 mg/kg), morphine (40 mg/kg) or morphine (40 mg/kg) plus CGS 10746B (0.5, 1, 2, 4, 8, 16, 24 and 32 mg/kg) were placed in an actimeter during a period of 90 min. In experiment 2, animals treated with CGS 10746B (0.5, 1, 3 and 10 mg/kg), morphine (40 mg/kg) or morphine (40 mg/kg) plus CGS 10746B (0.5, 1, 3 and 10 mg/kg) were conditioned following a procedure unbiased …
Pravastatin treatment causes a shift in the balance of hippocampal neurotransmitter binding densities towards inhibition
2009
Since pravastatin, a HMG-CoA reductase inhibitor, has recently been shown to reduce infarct volumes and glutamate release in a rat model of ischemic stroke, the aim of the present study was to investigate whether this neuroprotective effect may be due to a modulation of excitatory and inhibitory neurotransmitter receptors. Therefore, Wistar rats were treated six times in 4 days with pravastatin or saline and allowed to survive for 6 hours or 5 days (n=10 per time point and group), respectively. Using quantitative receptor autoradiography, ligand binding densities of [(3)H]MK-801, [(3)H]AMPA, and [(3)H]muscimol for labeling of NMDA, AMPA, and GABA(A) receptors were analyzed in sensorimotor c…
Long-Term Effects of Dietary Sodium Intake on Cytokines and Neurohormonal Activation in Patients With Recently Compensated Congestive Heart Failure
2009
Abstract Background A growing body of evidence suggests that the fluid accumulation plays a key role in the pathophysiology of heart failure (HF) and that the inflammatory and neurohormonal activation contribute strongly to the progression of this disorder. Methods and Results The study evaluated the long-term effects of 2 different sodium diets on cytokines neurohormones, body hydration and clinical outcome in compensated HF outpatients (New York Heart Association Class II). A total of 173 patients (105 males, mean age 72.5±7) recently hospitalized for worsening advanced HF and discharged in normal hydration and in clinical compensation were randomized in 2 groups (double blind). In Group …
Wasp venom injected into the prey's brain modulates thoracic identified monoaminergic neurons.
2005
The wasp Ampulex compressa injects a cocktail of neurotoxins into the brain of its cockroach prey to induce an enduring change in the execution of locomotory behaviors. Our hypothesis is that the venom injected into the brain indirectly alters the activity of monoaminergic neurons, thus changing the levels of monoamines that tune the central synapses of locomotory circuits. The purpose of the present investigation was to establish whether the venom alters the descending control, from the brain, of octopaminergic neurons in the thorax. This question was approached by recording the activity of specific identified octopaminergic neurons after removing the input from the brain or after a wasp s…