Search results for "Reserpine"
showing 10 items of 39 documents
Cytotoxicity of the indole alkaloid reserpine from Rauwolfia serpentina against drug-resistant tumor cells.
2015
Abstract Background: The antihypertensive reserpine is an indole alkaloid from Rauwolfia serpentina and exerts also profound activity against cancer cells in vitro and in vivo. The present investigation was undertaken to investigate possible modes of action to explain its activity toward drug-resistant tumor cells. Material and methods: Sensitive and drug-resistant tumor cell lines overexpressing P-glycoprotein (ABCB1/MDR1), breast cancer resistance protein (ABCG2/BCRP), mutation-activated epidermal growth factor receptor (EGFR), wild-type and p53-knockout cells as well as the NCI panel of cell lines from different tumor origin were analyzed. Reserpine's cytotoxicity was investigated by res…
Muscarinic inhibition of potassium-induced noradrenaline release and its dependence on the calcium concentration.
1975
1. Noradrenaline release from the isolated rabbit heart was evoked by perfusion with a medium containing 135 mM potassium and 17 mM sodium ions (high K+-low Na+). 2. The noradrenaline output in response to high K+-low Na+ was dose-dependently decreased by methacholine (0.625-320 muM) and this effect was reserved by atropine 1.44 mM. 3. Lowering the calcium concentration of high K+-low Na+ from 1.8-0.1125 mM decreased the noradrenaline output by 85%. The effect of methacholine, expressed as % inhibition of noradrenaline release, was potentiated by lowering of the calcium concentration. 4. Both at normal and lowered calcium concentrations the inhibitory action of methacholine was larger from …
Photochemical derivatization and fluorimetric determination of reserpine in a flow-injection assembly
1991
Abstract The fluorimetric flow-injection determination of reserpine was achieved with the drug being derivatized on-line by photoreaction. PTFE tubing was helically coiled around a germicide lamp located between the injection valve and detector. Two analytical procedures are proposed using either dilute acetic acid or pure methanol as the carrier stream. The influence of foreign compounds was studied and the method was applied to the determination of reserpine in pharmaceutical formulations.
Spectrophotometric Determination of Hydralazine with 2-Hydroxy-1-naphthaldehyde in Pharmaceuticals
1991
Abstract A new extraction-spectrophotometric method for the determination of hydralazine, based on its reaction with 2-hydroxy-1-naphthaldehyde at 25 °C, is described. The calibration curve was linear between 0.4 and 6 mg/mL of hydralazine. The molar absorbtivity of the product at 408 nm is 40 900 L · mol − 1 · cm − 1 . The method described was applied to the analysis of hydralazine in pharmaceutical preparations containing reserpine, hydrochlorothiazide, bendrofluorthiazine, propranolol, and other substances. The agreement with the U.S.P. XXI method was satisfactory for tablets and injections, but not for pellets.
The lack of the effect of DA-1 and DA-2 dopamine agonists on the isolated guinea-pig atria.
1987
1 The effects of dopamine and both DA-1 and DA-2 dopamine receptor agonists have been studied on the contractile force of electrically driven guinea-pig left atria and frequency of spontaneously beating right atria. 2 Pretreatment of animals with reserpine caused a parallel rightward shift of the concentration-response curve to dopamine of either preparation. 3 Propranolol, but not domperidone, shifted to the right the dose-response curve for the positive inotropic and chronotropic effects of dopamine. 4 Neither apomorphine, fenoldopam, bromocriptine nor piribedil had effects on the frequency and contractile force of the isolated guinea-pig atria. 5 These results suggest that DA-1 and DA-2 …
Co-transmitter mediated facilitation by sympathetic nerve stimulation of evoked acetylcholine release from the rabbit perfused atria preparation.
1995
Rabbit atria were isolated with the extrinsic right sympathetic and vagus nerves attached and perfused with Tyrode solution. Acetylcholine overflow was determined after labelling of the transmitter stores with [14C]choline and fractionation of the radioactivity on cation exchange columns. Sympathetic nerve stimulation (SNS, 2 Hz, 3 min) carried out together with vagus nerve stimulation (VNS, 2 Hz, 3 min), but each SNS pulse preceding a vagal one by 19 ms, caused a facilitation of acetylcholine overflow of about 60% versus independent controls in the absence of SNS. Antagonists of putative neurotransmitters were tested to find out the prejunctional mediator involved in the facilitation. The …
Electrical and mechanical activity of mammalian heart muscle fibres treated with papaverine
1977
The action of papaverine on electrical and mechanical activity was investigated in ventricular and atrial heart muscle fibres from guinea-pigs and cats. 1. Papaverine (10−5 M–5×10−5M) had positive, negative or no inotropic effects in ventricular preparations; positive inotropic effects were not observed after pretreatment of the animals with reserpine. In atrial preparations, papaverine (2×10−5M) had a positive inotropic effect that was independent of endogenously stored catecholamines. 2. The effects of isoprenaline and dibutyryl cyclic AMP were potentiated by papaverine (10−5 M–2×10−5M). 3. The action potential duration was always prolonged by papaverine in ventricular as well as in atria…
A standardization of the Novelty-Suppressed Feeding Test protocol in rats
2017
Tests based on hyponeophagia phenomena are the most widely used to check the efficacy and efficiency of new-generation chronic antidepressant treatments. Even so, these tests lack strict consensus about their methodology, which reduces their validity, reproducibility and makes translatability difficult. Therefore, after an extensive literature review on this subject, we propose a methodological protocol for the Novelty-Suppressed Feeding Test to normalize this situation. Animals were induced to a reserpine-induced depression model and were then chronically treated with duloxetine, desvenlafaxine or vehicle. After a 14-day treatment, a standardized Novelty-Suppressed Feeding Test was perform…
Depressive-like symptoms in a reserpine-induced model of fibromyalgia in rats.
2015
Since the pathogenesis of fibromyalgia is unknown, treatment options are limited, ineffective and in fact based on symptom relief. A recently proposed rat model of fibromyalgia is based on central depletion of monamines caused by reserpine administration. This model showed widespread musculoskeletal pain and depressive-like symptoms, but the methodology used to measure such symptoms has been criticized. Evidence relates the high prevalence of pain and depression in fibromyalgia to common pathogenic pathways, most probably focused on the monoaminergic system. The present study aims at a validation of the reserpine model of fibromyalgia. For this purpose, rats undergoing this model have been …
Hippocampal oscillatory dynamics and sleep atonia are altered in an animal model of fibromyalgia: Implications in the search for biomarkers
2019
The pathogenesis of fibromyalgia is still unknown. Core symptoms include pain, depression, and sleep disturbances with high comorbidity, suggesting alterations in the monoaminergic system as a common origin of this disease. The reserpine-induced myalgia (RIM) model lowers pain thresholds and produces depressive-like symptoms. The present work aims to evaluate temporal dynamics in the oscillatory profiles and motor activity during sleep in this model and to evaluate if the model mimics the sleep disorders that occur in fibromyalgia patients. Hippocampal and electromyogram activity were recorded in chronically implanted rats. Following 3 days of basal recordings, reserpine was administered on…