There are many clinical evidences supporting that ACTH and corticosteroids produce agitation and enhance anxiety and these effects are counteracted by an antianxiety drug like diazepam. Recent studies of the action mechanism of benzodiazepines suggested that both receptors of benzodiazepines and barbiturates are coupled to the GABA receptor-ionophore complex and that the diazepam effect on the central nervous system is associated with increase of extracellular brain adenosine content.
In this paper, the influences of aminophylline, the so-called `valium antagonist´ as an adenosine antagonist, and thiopental sodium on the diazepam-induced increase of plasma corticosterone and blood sugar levels in male mice were studies.
The results obtained were summarized as follows:
1. The normal plasma corticosterone level was little changed by each (lmg/kg) of flurazepam, chlordiazepoxide, and diazepam.
2. The plasma corticosterone level was significantly increased by diazepam (1 or 5mg/kg), aminophylline (5, 10, or 20mg/kg), and thiopental sodium (30 or 60 mg/kg).
3. The increasing effect of diazepam on plasma corticosterone level was significantly suppressed by
the pretreatment with aminophylline (10 or 20mglkg) and thiopental sodium (60mg/kg) but little af-
fected by the pretreatment with aminophylline (5mg/kg) and thiopental sodium (30mg/kg).
4. The blood sugar level was significantly increased by diazepam but little changed by aminophylline
and thiopental sodium.
5. The increasing effect of diazepam (lmg/kg) on blood sugar level was significantly enhanced by the pretreatment with aminophylline (10 or 20mg/kg) but significantly supressed by the pretreatment with thiopental sodium (30 or 60 mg/kg).
These results suggested that the mechanism of diazepam-induced increase of plasma corticosterone
level might be associated with rather other action sites such as adenosine receptors than the benzodiazepine receptor coupled to GABA receptor-ionophore complex and that the increasing action of diazepam on plasma corticosterone level might be dissociated with its increasing action´of blood sugar level.
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