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Biomedical subjects

E Nowakowska

Publications and source records attributed to E Nowakowska.

At least 55 records · Page 3Linked to original sources
PubMed1976

The influence of premedication with 6-OH-dopamine and long-term administration of thymoanaleptics on development of experimental arterial hypertension.

Administration of 6-OH-DA into the lateral cerebral ventricle did not prevent development of hypertension or influence the effects of administration of tricyclic antidepressant drugs (TA). Injection os 6-OH-DA intraperitoneally prevented development of hypertension, and TA apparently protected against the consequences of administration of 6-OH-DA.

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Synthesis, structure, and biological activities of some N-(4,5-dihydro-1H-imidazol-2-yl)-1,3-dihydrobenzimidazole derivatives.

A series of novel N-(4,5-dihydroimidazol-2-yl)-1,3-dihydrobenzimidazole derivatives 2a-d, 3a-d and 4a-p were prepared and their structure was determined by IR and NMR spectroscopic data as well as X-ray analysis of carbonitrile 2a. The compounds were studied as potential inhibitors of the human blood platelet aggregation induced by adrenaline or ADP. Compounds of type 3 proved efficacious for the reduction of arterial blood pressure upon intravenous administration to normotensive rats.

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Influence of olanzapine on cognitive functions and catalepsy in rats after single and chronic administration.

The aim of our investigations was to supplement the scarce information about behavioral effects of olanzapine and especially to find out if the effects change during prolonged treatment. It was established that at a dose of 0.5 mg/kg, which did not evoke sedation, olanzapine had distinct anxiolytic effects, both after acute and chronic treatment. Olanzapine improved memory in the maze test (food finding time), but only in chronic experiments after a lag of 14 days. Olanzapine at the dose of 0.5 mg/kg did not cause catalepsy but a higher dose of 1 mg/kg elicited strong sedating effects, which would interfere with the catalepsy test. The results of Porsolt's test (immobility time in swimming rats) were interesting because a shortening of immobility time occurred only after single drug injection. Our results are in agreement with the statement of other authors that olanzapine has greater potency in antagonizing responses mediated rather by 5-HT than D2 receptors.

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Comparative study of antithrombotic and antiaggregatory activity of acetylsalicylic acid, ticlopidine and a new noncarboxylic acid antiinflammatory pyrazine derivative HF90.

The action of acetylsalicylic acid, ticlopidine and a new pyrazine derivative HF90 selected in preliminary screenings (11, 18, 19) was studied by using the mouse antithrombotic assay according to DiMinno and Silver (22) and in vitro blood platelet aggregation method according to Born (23). Acute pulmonary thromboembolism was induced by injection of a mixture of collagen and epinephrine into the mouse tail vein. The effect of HF90, an acidic pyrazine derivative possessing active methylene moiety, administered at doses of 50 and 100 mg/kg, was compared to the action of the well established antithrombotic agents: ticlopidine (100 mg/kg) and acetylsalicylic acid (20 mg/kg). The compounds were administered i.p. in single doses 1 h and 24 h before the thrombotic challenge or once a day per three consecutive days before the thrombotic challenge. Ticlopidine appeared to provide the better protection against microembolism than acetylsalicylic acid although its effect has not manifested itself immediately after administration. The pyrazine derivative examined has a lower but significant antithrombotic activity. The chemical class of pyrazine derivatives with active methylene moiety (the so called pyrazine CH/NH-acids) (16) provides a new original antiinflammatory pharmacophore and HF90 may serve as the "lead compound" in the search for new agents of pharmacological interest.

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Behavioral and memory improving effects of mirtazapine in rats.

These experiments examined the effects of the antidepressant mirtazapine in several behavioral and memory tests. The tests were carried out on male Wistar rats weighing about 200 g. The drugs were injected 30 min before the tests. The aim of the locomotor activity test was to select a dose which had no influence on the motility of the animals and, at the same time, was active at least in one behavioral test. The chosen dose was 2.5 mg/kg. In the two-compartment exploratory test, 2.5 mg/kg of mirtazapine had a distinct anxiolytic effect after the first treatment, after 7 days the effect was weaker but still significant and it disappeared after 14 days. In the forced swimming test, the immobility time was shortened only after 14 days of administering the drug. In the maze test, mirtazapine shortened the food finding time (it improved memory) and counteracted memory loss induced by scopolamine. In the conditioned avoidance responses test (CARs), mirtazapine improved memory only after its earlier impairment by scopolamine. The authors cohclude, contrary to some published data, that after proper dose (adequate for other tests but not for the locomotor activity test), mirtazapine has a distinct memory improving activity or a memory restoring effect after scopolamine treatment.

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Reversal of stress-induced memory changes by moclobemide: the role of neurotransmitters.

Studies on animals have shown that chronic stress is able to evoke behavioral changes such as locomotor activity deficit, decreased sleep, reduced food and water consumption and impaired memory. Chronic stress produces changes in concentrations of neurotransmitters, mainly in the hippocampus. The hippocampus is a vulnerable brain structure that is involved in learning and memory functions. In this study, we investigated the effects of chronic stress procedure and moclobemide in rats, and the influence of chronic stress on the levels of monoamines: noradrenaline (NE), dopamine (DA) and serotonin (5-HT) in the rat hippocampus [as well as their metabolites: dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA)]. It was found out that chronic 21-day stress caused worsening of memory: the well trained rats after stress procedure lost their ability to find food quickly. Because of many errors in finding the way, the time these animals needed was on average 2.4-times longer than that of the control group. Single, as well as prolonged (21 days) treatment with moclobemide (10 mg/kg/day) counteracted the deficit of memory induced by chronic stress. In stressed animals, we observed an increase in DA, decrease in DOPAC, 5-HT and 5-HIAA and decrease in NE levels. Moclobemide modulated the changes in the levels of neurotransmitters in the hippocampus, decreasing their turnover. The results demonstrate that moclobemide improves memory impaired by stress. They suggest also that moclobemide has a modulatory effect on stress-induced neurotransmitter changes which may be of importance for the protective effect of the drug with regard to memory impairment.

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Effects of pethidine on central neurotransmitters: changes in the state of tolerance.

Cerebral concentrations of neurotransmitters: noradrenaline, dopamine, serotonin and GABA were assayed in male Wistar rats receiving either a single dose of pethidine, or a prolonged treatment with the drug (twice daily for 21 days, im), leading to tolerance development. In tolerant rats the GABA content in the cerebral tissue was increased, and the activity of serotonergic system (assessed from the changes in 5-hydroxyindoleacetic acid level and serotonin turnover rate) was augmented.

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Pharmacokinetic disposition of pethidine under tolerance.

Under tolerance, evoked by multiple doses of pethidine (PD), the serum and brain tissue content of PD was related to diminished analgesic activity. Even though in tolerant rats no enhancement of PD biotransformation in the liver could be recognized (as followed by the measurement of hepatic esterase and N-demethylase activity), the amounts of both PD and nor-PD excreted in urine were increased under tolerance. The authors conclude that the faster disposition of PD may contribute to the development of tolerance.

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Differences in the development of tolerance to various benzodiazepines.

Anticonvulsant, sedative and anxiolytic effects of the following benzodiazepines, administered chronically by the intraperitoneal route, were assessed: nitrazepam (NTZ), diazepam (DZ), oxazepam (OXZ), chlordiazepoxide (CDX) and temazepam (TMZ). The action of NTZ in tests for sedative, anticonvulsant and anxiolytic effects rapidly changed upon a repeated daily treatment, which suggests development of tolerance, while no tolerance developed to such effects of OXZ. The stimulating effect of DZ was found not earlier than after 5 weeks of chronic treatment, but no tolerance to the anxiolytic action was observed, and the anticonvulsant action was even potentiated. The stimulating action and tolerance to the anxiolytic effects of CDX and TMZ developed rapidly, but was accompanied with an only slight decrease in the anticonvulsant effect.

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Development of tolerance to pethidine in rats, pretreated or not, with beta-naphtoflavone or SKF 525 A.

Tolerance to the analgesic effect of pethidine (PD) in rats, treated with a dose of 15 mg/kg of the compound twice daily at 12 h intervals for 1-3 weeks, was assessed using both, heat and current irritating stimuli. Tolerance could be detected earlier by the current irritating method, than by the hot plate technique. Pretreatment with beta-naphtoflavone did only slightly affect the development of tolerance to the antinociceptive effect of PD. In contrast after one week of treatment with SKF 525 A PD retained its analgesic effect. The prolonged pretreatment with SKF 525 A did not prevent the development of tolerance to the analgesic effect of PD.

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Effect of multiple doses of clonazepam on the nitroreductase activity in hepatic microsomal preparation from rat.

The hepatic microsomal nitroreductase activity and urinary excretion of the sum of the main metabolites of clonazepam (CNZ) were investigated in rats that had received 7 daily injections of 2 mg/kg of the compound. Despite the significant decrease in CNZ nitroreductase activity, there was only poor correlation between the enzyme activity and excretion of the assayed metabolites.

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