Biomedical subjects

A Chodera

Publications and source records attributed to A Chodera.

At least 19 recordsLinked to original sources

PubMed2000

Behavioural effects of fluoxetine and tianeptine, two antidepressants with opposite action mechanisms, in rats.

The behavioural effects of two antidepressants with opposite molecular mechanisms, tianeptine 7-[(3-chloro-6,11-dihydro-6-methyldibenzo[c,f][1,2]thiazepin - 11-yl)amino]heptanoic acid S,S-dioxide, CAS 66981-73-5) 5 mg/kg p.o., a serotonin reuptake enhancer, and fluoxetine (+/-)-N-methyl-3-phenyl-3-[(alpha, alpha, alpha-trifluoro-p- tolyl)oxy]propylamine, CAS 54910-89-3) 5 mg/kg p.o., a serotonin reuptake inhibitor, were compared after single and prolonged administration (7 and 14 days) once daily). In all experiments the drug effects were noted at the peak activity time: 30 min after tianeptine and 60 min after fluoxetine administration. In the immobility time test both drugs had a shortening effect on immobility time only after prolonged administration or, in single treatment, after joint administration. A different pattern was observed in the two compartment test: both antidepressants showed anxiolytic effects after single and prolonged treatment. However, when the drugs were given in joint administration, the anxiolytic effects were entirely abolished after single as well as prolonged treatment. In reference spatial memory test (food finding time in the maze) tianeptine had no effect, whereas fluoxetine caused, after single and prolonged treatment, a very marked improvement of reference memory. Joint administration of both drugs resulted in worsening the effects on memory in comparison to fluoxetine alone, but the results were still significantly better vs. control. In the test for sedative action (in the Activity Meter AM-1, where the movements of the animals are counted electronically) only after prolonged treatment with tianeptine a diminished locomotor activity could be observed. It is concluded that in the action of the drugs (beside the effect on serotonin uptake) other mechanisms must play an important role. The diminished locomotor activity after tianeptine suggests an influence on the dopaminergic or GABA-Receptor system.

Animals↗

PubMed1999

Some behavioural effects of risperidone in rats: comparison with haloperidol.

Risperidone is a dopaminergic as well as a 5-HT2 antagonist. The drug was found to exert beneficial effects on both positive and negative symptoms of schizophrenia. Since recently, schizophrenia is regarded as a composite of not only positive and negative but also affective and cognitive symptoms, in this study the effects of risperidone compared with typical neuroleptic haloperidol, on affective and cognitive functions were investigated in rats (anxiolytic, antidepressive and memory tests). We found, that in contrast to haloperidol, risperidone had antidepressive, anxiolytic and memory enhancing effects. The results obtained correspond with favourable effects of risperidone on mood disturbances and cognitive functions of schizophrenic patients observed under clinical conditions.

Animals↗

PubMed1998

An anxiolytic-like effect of ondansetron disappears in oxazepam-tolerant rats.

In our experiments a drug from the group of 5-HT3 antagonists--ondansetron (OND)--has been used in rats developing tolerance to oxazepam (OXZ). After 7 days of oxazepam administration (5 mg/kg i.p.) a significant decrease in the anxiolytic behavior was observed in the Crawley test. In the rats already partly tolerant to oxazepam, an undiminished anxiolytic-like effect of ondansetron (single injection of 0.1 mg/kg i.p., seventh day) was observed. After 14 days of oxazepam administration its anxiolytic activity was even more diminished. A single injection of ondansetron 0.1 mg/kg restored the anxiolytic behavior: rise of BWT (black-white transition) and WSE (white square entrance). After 21 days the anxiolytic activity of oxazepam was totally abolished and the single injection of ondansetron did not restore the state of anxiolysis. The results show that the anxiolytic effects of ondansetron were not influenced in the first stages of tolerance development to oxazepam, but the drug was not able to produce an anxiolytic effect in the state of full tolerance to oxazepam (after 3 weeks).

Animals↗

PubMed1998

[Kava-kava preparations--alternative anxiolytics].

Since Cook's world cruises (1772-1775) there is written evidence of the use of kava-kava by the inhabitants of the Pacific Islands. In last decades kava-kava, an extract of the plant Piper methysticum was used in several European countries (drugs like Laitan, Antares, Viocava, Mosaro etc.). In the presented paper the authors describe the pharmacology, toxicology and pharmacokinetics of the active compounds of kava-kava the kavapyrones. The discussion concerning the therapeutic value of kavapyrones ends with the conclusion of the authors, that kava-kava may be a useful alternative for synthetic anxiolytics.

Animals↗

PubMed1998

Anxiolytic and memory improving effects of moclobemide.

The anxiolytic and memory enhancing effects of moclobemide (p-chloro-N-(2-morphinoethyl)benzamide, CAS 71320-77-9, Ro 11-1163), a reversible and selective monoamine A oxidase inhibitor, were investigated in rats. It was found that the drug had an anxiolytic activity lasting in chronic experiments over 2 weeks. The used dose of the drug did not change animal locomotion in activity cages. In memory experiments (food finding time in maze), moclobemide exerted a favorable effect only after a single administration. In rats with scopolamine-impaired memory, moclobemide attenuated the effects of scopolamine in single and chronic experiments.

Animals↗

PubMed1997

Comparison of the serum insulin and endothelin level in patients with essential and renovascular hypertension.

To evaluate whether a relationship exists between insulinaemia (increased in essential hypertension) and endothelin level, we determined insulin and endothelin-1-like (ET-1-Li) immunoreactivity in blood serum by radioimmunoassay (RIA) in essential (EH, n = 64) and renovascular (RVH, n = 36) patients with hypertension and in healthy subjects (controls, n = 44). The trials were carried out in fasting patients and after an oral glucose tolerance test (OGTT, 75 g). Each group of subjects had similar body mass index (BMI) values. The mean values of insulin level were significantly (P < 0.0001 in every case) elevated in patients with essential hypertension compared with renovascular and control subjects during the whole OGTT. There was no significant difference in insulin level between subjects with renovascular hypertension and controls. ET-1-Li immunoreactivity levels were significantly increased (P < 0.005 fasting; P < 0.01 after 1 and 2 h) throughout the whole test in the essential hypertensive group compared with controls; in renovascular hypertensive patients 2 h after glucose administration the analogous difference was not statistically significant (P < 0.05 fasting; P < 0.01 after 1 h). In all the investigated groups the mean value of ET-1-Li immunoreactivity increased and decreased in parallel to the changes in insulin concentration during the OGTT. The ET-1-Li level was positively correlated with insulin concentration with a statistical significance for patients with essential hypertension 1 h after load (r = 0.6578, P < 0.05). The border of the significance level correlation was obtained in essential hypertensive patients 2 h after load (r = 0.5227, P = 0.06) and in controls 1 h after glucose administration (r = 0.5465, P = 0.054). Our results indicate a mutual connection between insulinaemia and an endothelin set; their relevance for the pathogenesis of hypertension requires further research.

Adult↗

PubMed1997

[Inhibitory monoamine oxidases of the new generation].

This review deals with the new generation of selective and partly reversible monoamine oxidase (MAO) inhibitors. In contrast to the non selective inhibitors, used in the year 1957-1970, the selective inhibitors bind to and block only one of the two isoenzymes, MAO-A or MAO-B. The MAO-A inhibitors and part of the MAO-B inhibitors differ also from the classic drugs by their reversibility. The inhibition of MAO-A cause the rise of norepinephrine, dopamine and serotonin in the synaptic cleft, of MAO-B only of dopamine. The new inhibitors diminish also to some extent the reuptake of monoamines. The molecular action mechanism of the new drug generation is the same as in the non-selective drugs: increase of monoamines, near to the receptor, leads, after a number of intermediate steps, to activation of functional proteins in the cell. The selective block of one of the isoenzymes does not stop the metabolism of tyramine (from cheese, red wine), because this toxic compound is metabolised by both isoenzymes. The control of therapy with MAO-A inhibitors is easier, because of their reversibility. Selective inhibitors of MAO have found a secure place in therapy of depression (inh. of MAO-A, esp. Moclobemide) and Parkinson's disease (inh. of MAO-B, at this time mainly selegiline). Discussed is possible use of selective MAO-inhibitors for achieving an increase in cognitive function and protections of neurone cells from biochemical lesions.

Animals↗

PubMed1996

Amelioration of lupus-like autoimmune disease in NZB/WF1 mice after treatment with a blocking monoclonal antibody specific for complement component C5.

New Zealand black x New Zealand white (NZB/W) F1 mice spontaneously develop an autoimmune syndrome with notable similarities to human systemic lupus erythematosus. Female NZB/WF1 mice produce high titers of antinuclear antibodies and invariably succumb to severe glomerulonephritis by 12 months of age. Although the development of the immune-complex nephritis is accompanied by abundant local and systemic complement activation, the role of proinflammatory complement components in disease progression has not been established. In this study we have examined the contribution of activated terminal complement proteins to the pathogenesis of the lupus-like autoimmune disease. Female NZB/W F1 mice were treated with a monoclonal antibody (mAb) specific for the C5 component of complement that blocks the cleavage of C5 and thus prevents the generation of the potent proinflammatory factors C5a and C5b-9. Continuous therapy with anti-C5 mAb for 6 months resulted in significant amelioration of the course of glomerulonephritis and in markedly increased survival. These findings demonstrate an important role for the terminal complement cascade in the progression of renal disease in NZB/W F1 mice, and suggest that mAb-mediated C5 inhibition may be a useful approach to the therapy of immune-complex glomerulonephritis in humans.

Animals↗

PubMed1996

Pharmacological activity of fluoxetine.

Some SSRIs like fluvoxamine and zimeldine have already been investigated for their memory improving activity in humans and animals, with positive results. The purpose of this paper is to observe some activities of fluoxetine the known antidepressant on some control neuron system functions [3].

Animals↗

PubMed1994

Expression of recombinant transmembrane CD59 in paroxysmal nocturnal hemoglobinuria B cells confers resistance to human complement.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic disorder characterized by complement-mediated hemolytic anemia, pancytopenia, and venous thrombosis. These clinical manifestations arise from an underlying molecular defect of bone marrow stem cells. Specifically, somatic mutations in the phosphatidylinositol glycan class A gene result in the ability of blood cells to anchor complement-regulatory proteins (CD59 and DAF) to the cell surface via glycosyl phosphatidylinositol (GPI). In an attempt to circumvent the functional defect in PNH cells, a recombinant transmembrane form of CD59 (CD59-TM) was analyzed for the ability to regulate complement activity. Balb/3T3 stable transfectants expressing similar levels of either CD59-TM or native CD59 (CD59-GPI) were equally protected against human complement-mediated membrane damage. Treatment of these cells with phosphatidylinositol-specific phospholipase C failed to release CD59-TM from the cell surface. Retroviral transduction of GPI-anchoring deficient mouse L cells with CD59-TM resulted in surface expression of the protein and rendered these cells resistant to human complement-mediated membrane damage. Conversely, L cells transduced with CD59-GPI failed to express this protein on the cell surface. A GPI-anchoring deficient complement-sensitive B-cell line derived from a PNH patient was successfully transduced with CD59-TM, resulting in surface expression of the protein. The PNH B cells expressing CD59-TM were protected against classical complement-mediated membrane damage by human serum. Taken together, these data establish that a functional recombinant transmembrane form of CD59 can be expressed on the surface of GPI-anchoring deficient PNH cells and suggest that retroviral gene therapy with this molecule could provide a treatment for PNH patients.

3T3 Cells↗

PubMed1991

Studies on the involvement of opioid mechanism in the locomotor effects of benzodiazepines in rats.

The influence of the opioid receptor antagonist naloxone upon the reduced locomotor activity after administration of nitrazepam (NTZ) and upon the increased locomotion after chronic nitrazepam administration was tested. It was found that a single dose of naloxone counteracted both the reduced locomotion after acute administration of nitrazepam as well as the augmented locomotor activity after chronic application of nitrazepam. It is assumed that opioid mechanisms are involved in the locomotor effects of benzodiazepines.

Animals↗

PubMed1991

[Effect of flavonoid fractions of Solidago virgaurea L on diuresis and levels of electrolytes].

The flavonoid fractions of Solidago virgaurea L.S. gigantea Ait., S. canadensis var. canadensis and S. canadensis var. "scabra" flowers were administrated p.o. to rats and showed diuretic activity. Increase in overnight diuresis reached 57-88%. Decrease of overnight excretion of potassium and sodium also occurred after administration of form examined fractions. The flavonoids from S. virgaurea and S. canadensis var. canadensis caused increased excretion of calcium with urine.

Administration, Oral↗

PubMed1988

Decrease in [3H]flunitrazepam receptor binding in rats tolerant to the effects of nitrazepam.

Studies were performed to evaluate the binding of [3H]flunitrazepam to cell membranes from the brain cortex of rats that were made tolerant, by the i.p. administration of nitrazepam once daily, to the anxiolytic and sedative effects (after 14 days) and the anticonvulsant action (electroshock, after 28 days) of nitrazepam. A significant decrease in the number of specific [3H]flunitrazepam binding sites was found only in the group that was tolerant to the anticonvulsant effect. The same experiments were also carried out with oxazepam. Since there were no signs of tolerance, the administration of the drug, 10 mg/kg once daily i.p., was continued for 6 weeks. No tolerance occurred and there were no changes in [3H]flunitrazepam binding site density. We conclude that tolerance to the anticonvulsant effect of nitrazepam could be related to the down-regulation of the benzodiazepine receptors.

Animals↗

PubMed1988