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Biomedical subjects

G Drexler

Publications and source records attributed to G Drexler.

36 records · Page 2Linked to original sources
PubMed1984

Evidence for association of a high affinity avermectin binding site with the benzodiazepine receptor.

Avermectin B1a concentrations corresponding to the KD value of a specific high affinity binding site for [3H]avermectin B1a are sufficient to stimulate the specific high affinity binding of [3H]flunitrazepam to its receptors. This stimulation of [3H]flunitrazepam binding by low concentrations of avermectin B1a was enhanced by chloride ions and picrotoxinin and reduced by the GABA agonists THIP and PSA. The similar modulation by chloride ions, GABA agonists and picrotoxinin and the resistance against washing of membranes of avermectin B1a bound to its specific high affinity binding site or to the site modulating [3H]flunitrazepam binding indicate a close association of the specific high affinity binding site for [3H]avermectin B1a with the GABA-benzodiazepine receptor complex.

Animals↗
PubMed1984

Properties of a high affinity binding site for [3H]avermectin B1a.

The specific high affinity binding of [3H]avermectin B1a was investigated in membranes from several rat brain regions. Binding occurred rapidly, was reversible and partially dependent on the presence of chloride ions in the incubation medium. Specific high affinity binding of [3H]avermectin B1a was partially inhibited by GABA receptor agonists and this effect was blocked by GABA receptor antagonists. Pentobarbital and etazolate inhibited, and picrotoxin, picrotoxinin and IPTBO stimulated high affinity binding of [3H]avermectin B1a. All these effects were influenced by the presence of chloride ions in the incubation medium. The results indicate that the high affinity binding site of [3H]avermectin B1a is associated with the GABA-benzodiazepine receptor-chloride ion channel complex.

Animals↗
PubMed1983

Properties of [3H]flunitrazepam binding to different benzodiazepine binding proteins.

Membranes from cerebellum or hippocampus were incubated with various concentrations of [3H]flunitrazepam in the absence or presence of diazepam, Cl 218 872 or ethyl-beta-carboline-3-carboxylate (beta-CCE). After binding equilibrium of [3H]flunitrazepam had been established, the membranes were either filtered for determination of reversible binding or were irradiated with UV light for determination of irreversible binding. Irradiated membranes were then subjected to SDS-polyacrylamide gel electrophoresis and fluorography. Individual photolabeled proteins were identified, appropriate sections cut out of the gel, and the radioactivity in the gel pieces measured. The results indicate that [3H]flunitrazepam binding to individual benzodiazepine binding proteins and its inhibition by various drugs can be measured by the present technique and support previous evidence for the independent existence of various proteins irreversibly labeled by [3H]flunitrazepam and their possible association with different benzodiazepine receptors.

Animals↗
PubMed1983

Irreversible binding of [3H]flunitrazepam to different proteins in various brain regions.

Irreversible photolabeling by [3H]flunitrazepam of four proteins with apparent molecular weights 51,000 (P51), 53,000 (P53), 55,000 (P55), and 59,000 (P59) was investigated in various rat brain regions by SDS-polyacrylamide gel electrophoresis, fluorography, and quantitative determination of radioactivity bound to proteins. On maximal labeling of these proteins, only 15-25% of [3H]flunitrazepam reversibly bound to membranes becomes irreversibly attached to proteins. Results presented indicate that for every [3H]flunitrazepam molecule irreversibly bound to membranes, three molecules dissociate from reversible benzodiazepine binding sites. This seems to indicate that these proteins are either closely associated or identical with reversible benzodiazepine binding sites, and supports the hypothesis that four benzodiazepine binding sites are associated with one benzodiazepine receptor. When irreversible labeling profiles of proteins P51, P53, P55, and P59 were compared in different brain regions, it was found that labeling of individual proteins varied independently, supporting previous evidence that these proteins are associated with distinct benzodiazepine receptors.

Animals↗
PubMed1982

[Determination of the effective dose equivalent in gynecologic radium therapy].

In this study, the authors describe how to determine the effective dose equivalent absorbed by occupationally exposed persons during a gynecologic radium therapy. The observed irradiation conditions of the physician and the medical staff are approximated by a standard geometry, for which conversion factors between the measured personal dose, the effective dose equivalent and different organ doses, respectively, are calculated. The results are job-specific conversion factors between dose to a personal dosimeter and the effective dose equivalent for the occupationally exposed persons involved. According to the individual tasks, these factors are between 0.59 and 1.13.

Female↗