Über die Wirkung von Barbituraten bei Ratten verschiedenen Alters
SchlüsselwörterNarkose Körpertemperatur Barbiturate Konzentration in Blut und Gehirn Altersdifferenzen
In rats of two age-groups the effects and concentrations in blood and brain of hexobarbital, barbital and thiopental have been studied.
The sleeping time after hexobarbital is longer in old rats than in just matured animals (3 months of age) because the enzymatic oxidation of hexobarbital in old rats is slower.
After barbital which is eliminated chemically unchanged, the duration of anaesthesia is equal in both age groups.
The duration of thiopental anaesthesia with small doses is not different in the two age groups. At a higher dose, however, the larger extracerebral volume in the older animals becomes significant so that the older rats do not sleep as long as the younger ones.
When 45 mg/kg or more of thiopental has been given, the drug concentration in the brain remains above the anaesthetic level, even after the extracerebral volume has been filled up. Therefore as a first approximation sleeping time becomes a function of metabolic degradation of thiopental which is slower in old than in young rats as with hexobarbital.
Regarding the time course of the fall and recovery of body temperature during narcosis at 22° C there was no significant difference between the two age groups.
Key-WordsNarcosis Body Temperature 3 Barbiturates Concentration in Blood and Brain Age Differences
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