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Biomedical subjects

A Chodera

Publications and source records attributed to A Chodera.

At least 73 records · Page 4Linked to original sources
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Pharmacokinetic aspects of habituation to benzodiazepines.

In state of tolerance to the sedative effect of nitrazepam (NTZ) its pharmacokinetic properties are changed: the absorption is slowed down, the elimination, in contrast, is accelerated due to the rapid biotransformation. The NTZ content in brain tissue is increased significantly with respect to the brain levels of animals treated with a single dose of NTZ. In animals of only moderate intensity of tolerance produced by oxazepam (OX) the brain concentrations of OX are correlated with the developed tolerance.

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Development of tolerance to benzodiazepines. I. Changes in the systems of central nervous system neurotransmitters during long-term administration of nitrazepam.

A purpose of the study was determination of the relationships between the brain levels of neuro-mediators: noradrenaline (NA), dopamine (DA), 5-hydroxytryptamine (5-HT) and gamma-aminobutyric acid (GABA) and the development of tolerance to the sedative and anticonvulsive action of Nitrazepam. It was found that during tolerance development the GABA level increased in the cerebral tissue and changes appeared in the activity state of the serotoninergic system.

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On P-chlorphenylalanine interference with phenobarbital formation from primidone.

Premedication with PCPA antagonized in rats the anticonvulsant activity of Primidone and of other drugs against seizures evoked by electroshock. Only in the case of Primidone, however, the anticonvulsant activity could not be re-established by increasing the dosage. Our investigations have shown that PCPA caused a strong inhibition of the conversion of Primidone to phenobarbital, both in vivo and in vitro.

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Studies on cyproheptadine-amphetamine interaction after pretreatment with 6-hydroxydopamine.

6-hydroxydopamine (6-OH-DA) and cyproheptadine (CPH) exerted a lowering effect on blood amphetamine (AMPH) level in rats, at the same time the content of AMPH in the brain was elevated and the simultaneously recorded stereotypy was higher than in controls. After joint premedication with 6-OH-DA and CPH, however, no cumulative effect on AMPH brain level was seen, the highest AMPH elevation in whole brain as well as in corpus striatum occurred in animals premedicated with 6-OH-DA only. In spite of that, the highest stereotypy scores were noted after joint premedication with both substances. This may indicate that CPH premedication causes a rise in AMPH stereotypy mainly by pharmacodynamic interaction, though the elevation of the content of AMPH in the brain after CPH and 6-OH-DA must be of some influence as well. A further result is worth noting. After destroying peripheral adrenergic structures by 6-OH-DA a change from a two-compartment to a one-compartment model of AMPH kinetics occurred. This indicates that these structures may play the role of the second compartment or a part of it.

Amphetamine↗
PubMedDate not supplied

Development of tolerance to benzodiazepines. II. Baclofen effect on the activity of rats during tolerance to the sedative action of nitrazepam and oxazepam.

It was demonstrated that baclofen, a GABA-ergic agent, exerted a sedative effect in rats with tolerance to the sedative action of oxazepam and nitrazepam induced by administration of these drugs during several weeks. After one dose baclofen alone reduced the motor activity of rats without potentiating the effects of benzodiazepines. During long-term administration of baclofen tolerance developed also to its sedative action.

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The influence of a new antiarrhythmic drug, Craviten (M-71) on coronary flow.

Craviten (M-71) increases the coronary flow, depresses the rate of contractions, and transiently depresses the contractile force of the cat heart in vitro and in situ. As the action of the drug is short-lasting, its usefulness in treatment of acute cardiac insufficiency accompanied by pain is suggested. It is also potentially useful in cardiac insufficiencies accompanied by arrhythmia.

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Investigations on the interaction between cyproheptadine and amphetamine.

The effect of cyproheptadine (CPH) given in doses of 1.25 and 5 mg/kg intraperitoneally one hour before administration of D-(+)-amphetamine (AMPH) 5 mg/kg subcutaneously was studied. A moderate increase was observed in the intensity of amphetamine-induced stereotypy and a significant rise in the number of rearings after premedication with CPH 5 mg/kg. In pharmacokinetic investigations the serum level of AMPH was found to be decreased in the animals after CPH premedication. The biological half-time of AMPH in the blood was reduced after premedication with CPH 5 mg/kg. On the other hand, the level of amphetamine rose in the brain following premedication with CPH in both doses. These results suggest that the rise in brain AMPH level could be responsible for intensification of AMPH effects induced by CPH premedication.

Amphetamine↗
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Antiarrhythmic properties of Craviten (M-71) in cats and rabbits.

Preparation M-71 (Craviten, Polfa) possesses strong antiarrhythmic properties. It prevents development of cardiac arrhythmia evoked by BaCl2, ouabain and adrenaline in cats and rabbits, and abolishes the already developed arrhythmias. It prevents the aconitine-evoked arrhythmia only in rabbits.

Aconitine↗
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The influence of a new antiarrhythmic drug, Craviten (M-71) on the circulatory system in cats.

Craviten, a newly synthesized ester of optically active 2-aminobutanol-1, produced in cats hypotension and inhibited excitability of sinus node and atrio-ventricular and intraventricular conduction. It acts as a spasmolytic on the isolated rabbit ileum, being approx. 100 times as potent as papaverine. Studies with drugs affecting the vegetative system indicate that the hypotensive and spasmolytic action of Craviten consists in a direct depressing action on smooth musculature.

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Studies on the effect of cystamine on imipramine metabolism in radiation sickness.

Investigations were carried out for elucidating the effect of cystamine on the metabolism of imipramine in rats irradiated with a dose of 600 R. The investigations were based on determination of desmethylimipramine, the principal metabolite of this drug. It was found that cystamine reduced the serum imipramine level to control values but had no effect decreasing the level of desmethylimipramine. It caused also no fall in the concentration of this metabolite in brain tissue and even it raised this concentration. The authors explained these findings as a result of secondary resorption of desmethylimipramine into the blood stream, and a result of changed activity of beta-glucuronidase, these mechanisms being partly responsible for the overall effect.

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Cystamine effect on the pharmacokinetics of imipramine in radiation sickness.

Investigations were carried out on the effect of cystamine premedication (100 mg/kg) before irradiation with 600 R on imipramine (40 mg/kg) kinetics in male Wistar rats. It was found that cystamine prevented changes in blood imipramine level in the irradiated animals but it protected additionally the process of drug elimination from the blood (T 1/2 beta in controls = 1.67 h, in irradiated = 2.38 h, in irradiated premedicated = 4.01 h).

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Tolerance to a new class of non-benzodiazepine anxiolytics.

The development of tolerance to the pharmacodynamic effects of azopirone (buspirone) and imidazopyridines (alpidem and zolpidem) was investigated. It was found that tolerance to the anxiolytic effect of buspirone develops only after 42 days of administration (twice daily). Of the imidazopyridines alpidem showed an anxiolytic activity, while after zolpidem only a sedative activity was seen. No tolerance to the anxiolytic and sedative activity of the evaluated imidazopyridines could be detected. On the other hand tolerance appeared in the conditioned avoidance response test (evaluating learning and memory).

Animals↗
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Pharmacodynamics and pharmacokinetics of psycholeptic drugs in the course of radiation disease. The effect of premedication with cystamine on pharmacodynamics and Pharmacokinetics of nitrazepam.

Pharmacodynamics and pharmacokinetics of psycholeptic drugs in the course of radiation disease (I). Effect of premedication with cystamine on pharmacodynamics and pharmacokinetics of nitrazepam. Acta Physiol. Pol. 1977, 28 (2): 161--168. In the experiments carried out on rats the radiation disease was evoked by exposure to 600 R. The strongest radioprotective action of cystamine was found on the 3-rd day of radiation disease. The tendency to normalization of both the pharmacodynamics (exploring mobility and anticonvulsant action) and pharmacokinetics of nitrazepam in the animals premedicated with cystamine was described.

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Changes in pharmacodynamics and pharmacokinetics of psycholeptic drugs in the course of radiation disease. Effects of premedication with cystamine on dynamics and kinetics of thioridazine.

Changes in pharmacodynamics and pharmacokinetics of psycholeptic drugs in the course of radiation disease. Effect of premedication with cystamine on dynamics and kinetics of thioridazine. Acta Physiol. Pol. 1977, 28 (2): 169--179. The effect of premedication with cystamine (100 mg/kg) applied before irradiation (600 R) on exploring mobility and cataleptic action of thioridazine was investigated in rats. The levels of thioridazine in blood serum, brain tissue and in bile were determined. It was found that cystamine prevents the changes in dynamics of thioridazine action in radiation disease through abolition of disturbances in kinetics of this drug. Half-life period of thioridazine was found to be reduced and its level in the brain tissue was diminished in the irradiated, cystamine-pretreated animals in comparison with the irradiated, untreated ones.

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Effect of thymoanaleptic agents on the course of experimental arterial hypertension and catecholamine content in tissues and urine.

Experimental hypertension was induced in rats by two methods. In the course of hypertension development the rats of experimental groups were treated with following tricyclic antidepressive agents: Imipramine, Opipramol, Amitriptylline and Nortriptylline injected in doses of 5.0 or 0.5 mg per 1 kg of body weight. Higher doses of the above drugs inhibited the development of hypertension, whereas the lower doses had no effect on arterial blood pressure.

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Pharmacodynamics and pharmacokinetics of psycholeptic drugs in the course of radiation disease. Effect of premedication with metanabol on dynamics and kinetics of nitrazepam.

The effect of metanabol given to rats before irradiation (600 R) on exploring motility and cataleptic action of nitrazepam was investigated. The level of nitrazepam in the blood plasma and urine was determine. Most evident radioprotective effect of metanabol was found on 3rd day after irradiation. The drug inhibited the inhibited the increased response of the rats to the anticonvulsive action of nitrazepam and prevented the pharmacokinetic disturbances appearing in the course of radiation disease.

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