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At least 667 records · Page 37Linked to original sources
PubMed1997

Effects of a new centrally acting muscle relaxant, NK433 (lanperisone hydrochloride) on spinal reflexes.

(-)-(R)-2-methyl-3-(1-pyrrolidinyl)-4'-trifluoromethylpropiophenone++ + monohydrochloride, lanperisone hydrochloride (NK433) administered intravenously or orally depressed the mono- and polysynaptic reflex potential, dorsal root reflex potential, flexor reflex mediated by group II afferent fibers, patellar and flexor reflexes. These effects were reduced by spinal transection. NK433 inhibited the facilitation of the flexor reflex mediated by group II afferent fibers that was induced by intrathecal administration of noradrenaline-HCl. (+)-(1R,2R)-2-methyl-3-(1-pyrrolidinyl)-1-(4-trifluoromethylphenyl)-1-pr opanol (LPS-9)-HCl, a metabolite of NK433, also inhibited the spinal reflexes. Given orally, NK433 had effects more than three times stronger and tending to be longer-lasting than those of eperisone-HCl. These results suggest that NK433 exerts a non-selective inhibition on spinal reflexes and that inhibition of the descending noradrenergic tonic facilitation within the spinal cord is involved in the mechanism of spinal reflex depression by NK433. LPS-9 could contribute to the potent activity of NK433 after oral administration.

Administration, Oral↗
PubMed1998

3-4-Methylenedioxymethamphetamine-induced acute changes in dopamine transporter function.

The acute effects of the amphetamine designer drug, 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy'), on dopamine transporter function in rat striatum were investigated and compared to other psychostimulants known to influence monoaminergic systems. A single MDMA injection (10-20 mg/kg; s.c.) caused a dose-related decrease in [3H]dopamine uptake into striatal synaptosomes prepared 1 h after MDMA administration. This rapid effect on [3H]dopamine uptake returned to control levels 24 h after treatment. A single administration of other amphetamine analogs, such as methamphetamine (15 mg/kg; s.c.), p-chloroamphetamine (10 mg/kg; i.p.) or methcathinone (30 mg/kg; s.c.), also rapidly decreased striatal [3H]dopamine uptake. In contrast, a single or multiple administrations of cocaine (30 mg/kg; i.p.) had no effect on [3H]dopamine transport into striatal synaptosomes. These changes in dopamine transporter activity by the amphetamine analogs may occur via reactive oxygen species-mediated mechanisms.

Animals↗
PubMed1999

Inhibition of plasma membrane monoamine transporters by beta-ketoamphetamines.

Methcathinone and methylone, the beta-ketone analogues of methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA), respectively, were tested for neurotransmitter uptake inhibition in vitro. The beta-ketones were threefold less potent than the nonketo drugs at inhibiting platelet serotonin accumulation, with IC(50)'s of 34.6+/-4.8 microM and 5.8+/-0.7 microM, respectively. Methcathinone and methylone were similar in potency to methamphetamine and MDMA at catecholamine transporters individually expressed in transfected glial cells. For dopamine uptake, IC(50)'s were 0.36+/-0.06 microM and 0.82+/-0.17 microM, respectively; for noradrenaline uptake, IC(50) values were 0.51+/-0.10 microM and 1. 2+/-0.1 microM, respectively. In chromaffin granules, IC(50)'s for serotonin accumulation were 112+/-8.0 microM for methcathinone and 166+/-12 microM for methylone, 10-fold higher than the respective values for methamphetamine and MDMA. Our results indicate that methcathinone and methylone potently inhibit plasma membrane catecholamine transporters but only weakly inhibit the vesicle transporter.

3,4-Methylenedioxyamphetamine↗
PubMed2001

In vitro glucuronidation of xanthohumol, a flavonoid in hop and beer, by rat and human liver microsomes.

Xanthohumol (XN) is the major prenylated flavonoid of hop plants and has been detected in beer. Previous studies suggest a variety of potential cancer chemopreventive effects for XN, but there is no information on its metabolism. The aim of this study was to investigate in vitro glucuronidation of XN by rat and human liver microsomes. Using high-performance liquid chromatography, two major glucuronides of XN were found with either rat or human liver microsomes. Release of the aglycone by enzymatic hydrolysis with beta-glucuronidase followed by liquid chromatography/mass spectrometry and nuclear magnetic resonance analysis revealed that these were C-4' and C-4 monoglucuronides of XN.

Animals↗
PubMed1976

Liquid chromatography of neohesperidin dihydrochalcone.

The determination of a number of impurities in neohesperidin dihydrochalcone is described, as well as the determination of neohesperidin dihydrochalcone in food products. A reversed-phase chromatographic system is used, with octadecyltrichloro-silane-treated silica gel as chemically bonded stationary phase and methanol-water as mobile phase; a detailed procedure for preparing the packing material is given, and the dependence of the amount of bonded stationary phase on the humidity of the silica gel before the bonding reaction is shown. The glass column was packed at 350 atm in a steel pressure vessel, with use of a slurry-packing technique; details are given of the pressure vessel and of the packing method. Chromatograms are reproduced to show the performance of such columns in this type of analysis.

Chalcone↗
PubMed1999

Quantitative analysis of xanthohumol and related prenylflavonoids in hops and beer by liquid chromatography-tandem mass spectrometry.

A method for quantitation of six prenylflavonoids (xanthohumol, isoxanthohumol, desmethylxanthohumol, 6- and 8-prenylnaringenins and 6-geranylnaringenin) in hops and beer by HPLC-tandem mass spectrometry has been developed. The method allows direct analysis of beer and crude methanolic extracts of hops. After HPLC separation, prenylflavonoids were detected by positive ion multiple-reaction monitoring using a triple-quadrupole mass spectrometer equipped with a heated nebulizer--atmospheric pressure chemical ionization interface. The accuracy and precision were evaluated by replicate analyses of (spiked) samples. Thirteen commercial beers were analysed with the method. Isoxanthohumol, formed by isomerization of xanthohumol during the brewing process, was the most abundant flavonoid in hopped beers, ranging from 0.04 to 3.44 mg/l.

Beer↗
PubMed1999

Chiral resolution of basic drugs by capillary electrophoresis with new glycosaminoglycans.

New glycosaminoglycans, fucose-containing glycosaminoglycan (FGAG) and depolymerized holothurian glycosaminoglycan (DHG), were investigated as chiral additives for the separation of drug enantiomers by capillary electrophoresis. The average molecular masses of FGAG and DHG were estimated to be about 59,000 and 14,000, respectively. A variety of basic drug enantiomers were resolved using 10 mM phosphate buffer, pH 5.0, containing 3% FGAG or DHG. Since chiral recognition properties of FGAG and DHG are different, some drug enantiomers were only separated by using FGAG or DHG. With regard to comparison of chiral recognition abilities of FGAG and DHG with other chiral selectors, tolperisone and eperisone enantiomers were not separated with alpha- or beta-cyclodextrin, or heparin as the chiral additives, but were separated with FGAG and DHG. The results obtained reveal that FGAG and DHG are useful as the chiral selectors for separations of drug enantiomers by CE, and that they could be complementarily used with other chiral additives.

Buffers↗
PubMed1979

Cardiac electrophysiologic effects of etafenone hydrochloride (Dialicor), a new antiarrhythmic agent.

The electrophysiologic effects of etafenone hydrochloride (Dialicor) were studied in isolated rabbit hearts and canine or rabbit cardiac tissues with intracellular microelectrode techniques. The concentration range used was 0.25-10 mg/L, except in experiments with direct addition of etafenone into the tissue bath. Etafenone depressed automaticity in the sinus node, atrioventricular junction and Purkinje fibers at concentrations not affecting the action potential contour. In both atrial and ventricular fibers, etafenone prolonged the action potential duration and total refractory period. The action potential upstroke was slowed and conduction time increased. Higher concentrations reduced the resting potential, causing incomplete depolarization. Atrial action potentials were affected at lower concentrations than ventricular and Purkinje action potentials. Occasi-nally, etafenone produced localized conduction block within the atria, usually sparing internodal conduction. In electrically driven hearts, direct recording of His bundle potential as well as surface electrograms revealed marked prolongation of intraatrial and intranodal conduction times, with some increase in His-Purkinje and ventricular conduction times. Depression of atrioventricular conduction was insignificant under sinus rhythm. Possible therapeutic implications of these electrophysiologic effects are discussed.

Action Potentials↗
PubMed1986

Propafenone for the treatment of refractory complex ventricular ectopic activity.

The results of therapy with propafenone were evaluated in 45 patients with complex ventricular ectopic activity that had been refractory to a mean of 3.8 antiarrhythmic drugs. The cardiac diagnoses were ischemic heart disease (in 16 patients), cardiomyopathy (in 7), mitral valve prolapse (in 7), mitral valve prolapse (in 7), idiopathic ventricular ectopic beats (in 6), valvular heart disease (in 5), and hypertension (in 4). The frequency of ventricular ectopic beats was established after therapy with antiarrhythmic agents had been discontinued. Patients then received propafenone during a dose-ranging protocol. An effective response was defined as a reduction in total ventricular ectopic beats of 80% or more. During dose ranging, therapy failed in four patients because of side effects, in eight because of a reduction in ventricular ectopic beats of less than 80%, and in three because of an aggravation of the arrhythmia. Thirty patients had a reduction in total ventricular ectopic beats of 80% or more. During a mean follow-up of 12.4 months, therapy failed in 1 patient because of sustained ventricular tachycardia and in 7 because of intolerable side effects; 22 patients continued to receive propafenone. PR and QRS intervals were significantly prolonged (P = 0.001), but the corrected QT interval and the heart rate were unchanged. The mean trough plasma level of propafenone associated with an effective response was 756 ng/ml, and that associated with intolerable side effects was 920 ng/ml. Thus, in patients with refractory complex ventricular ectopic beats, propafenone was effective and well tolerated initially in 67% of patients and during long-term administration in 49%, and toxicity was minor in most patients.

Adult↗