Effects of systematically administered polyamines on imipramine immobility action in rats.
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Biomedical subjects
D Cenajek-Musiał
Publications and source records attributed to D Cenajek-Musiał.
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↗
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.
Animals↗
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.
Animals↗