L P Davies

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The effects of several purines and the purine uptake inhibitor, dipyridamole, on the binding, to rat brain membranes, of 4 benzodiazepines with different pharmacological specificities were studied. While all purines tested displaced the binding of [3H](+)-3-methyl-clonazepam and [3H]Ro15-1788, selective agonist and antagonist ligands respectively for(More)
We have used the adenosine-stimulated adenylate cyclase of guinea-pig brain to examine the potency of diazepam as an adenosine uptake inhibitor. Diazepam at concentrations in the range 10--500 microM stimulates the production of cAMP in incubated slices of guinea-pig cerebral cortex, with maximal fivefold stimulations over basal levels by 200 microM(More)
The tricyclic anticonvulsant carbamazepine inhibited the binding of [3H]phenylisopropyladenosine (PIA) to rat brain membranes with a K1 value of 44 microM, which is in the range of therapeutic levels of this drug in brain and serum. Other anticonvulsants and tricyclic antidepressants had little effect on PIA binding. Carbamazepine weakly inhibited adenosine(More)
A large number of nitrogen heterocycles structurally related to caffeine and theophylline have been tested for activity as adenosine antagonists. Preliminary screening, utilizing displacement of [3H]N6-phenylisopropyladenosine (PIA) binding to rat brain membranes, identified several pyrazolo[3,4-d]pyrimidines with potential antagonist activity. These were(More)
The ATP content of the cholinergic electromotor nerves of Torpedo marmorata has been measured. After freezing and thawing of pieces of nerve, their ATP content dropped rapidly to about 5% of that of pieces extracted immediately. The amount of ATP in nerves incubated in Torpedo Ringer remains at a high level over a long period. In nerves ligated for seven(More)
At therapeutic concentrations the tricyclic anticonvulsant carbamazepine inhibited the binding of the adenosine analogue [3H]L-N6-phenylisopropyladenosine ([3H]PIA) to rat brain membranes (Ki = 46 microM) in vitro. Carbamazepine interacted much less potently with muscarinic cholinergic, beta-adrenergic, gamma-aminobutyric acid, or L-glutamate binding sites.(More)