Affinities of barbiturates for the GABA-receptor complex and A\(_1\) adenosine receptors: A possible explanation of their excitatory effects
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- The effects of barbiturates on the GABA·receptor complex and the A\(_1\) adenosine receptor were studied. At the GABA-receptor complex the barbiturates inhibited the binding of [\(^{35}\)S]t-butylbicyclophosphorothionate [\(^{35}\)S]TBPT) and enhanced the binding of [\(^3\)H]diazepam. Kinetic and saturation experiments showed that both effects were allosteric. Whereas all barbiturates caused complete inhibition of [\(^{35}\)S]TBPT binding, they showed varying degrees of maximal enhancement of [\(^3\)H]diazepam binding; (±)methohexital wasThe effects of barbiturates on the GABA·receptor complex and the A\(_1\) adenosine receptor were studied. At the GABA-receptor complex the barbiturates inhibited the binding of [\(^{35}\)S]t-butylbicyclophosphorothionate [\(^{35}\)S]TBPT) and enhanced the binding of [\(^3\)H]diazepam. Kinetic and saturation experiments showed that both effects were allosteric. Whereas all barbiturates caused complete inhibition of [\(^{35}\)S]TBPT binding, they showed varying degrees of maximal enhancement of [\(^3\)H]diazepam binding; (±)methohexital was idenafied as the most efficacious compound for this enhancement. At the A\(_1\) adenosine receptor all barbiturates inhibited the binding of [\(^3\)H]N\(^6\)-phenylisopropyladenosine (\(^3\)H]PIA) in a competitive manner. The comparison of the effects on [\(^3\)H]diazepam and [\(^3\)H]PIA binding showed that excitatory barbiturates interact preferentially with the A\(_1\) adenosine receptor, and sedative/anaesthetic barbiturates with the GABA-receptor complex. It is speculated that the interaction with these two receptors might be the basis of the excitatory versus sedative/ anaesthetic properties of barbiturates.…
Autor(en): | M. J. Lohse, S. Böser, Karl-Norbert Klotz, U. Schwabe |
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URN: | urn:nbn:de:bvb:20-opus-60250 |
Dokumentart: | Artikel / Aufsatz in einer Zeitschrift |
Institute der Universität: | Medizinische Fakultät / Institut für Pharmakologie und Toxikologie |
Sprache der Veröffentlichung: | Englisch |
Erscheinungsjahr: | 1987 |
Originalveröffentlichung / Quelle: | Naunyn-Schmiedeberg's Archives of Pharmacology (1987) , 336, 211-217. |
Allgemeine fachliche Zuordnung (DDC-Klassifikation): | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Normierte Schlagworte (GND): | Toxikologie |
Freie Schlagwort(e): | Adenosine receptors; Barbiturates; GABA-receptor complex |
Datum der Freischaltung: | 08.12.2011 |
Lizenz (Deutsch): | Deutsches Urheberrecht |