Abstract
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1.
The olfactory cortex slice preparation from guinea-pig has been used to test compounds which inhibit the cellular uptake of adenosine.
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2.
The uptake inhibitors dipyridamole (0.1–10 μmol/l), dilazep (1–10 μmol/l) nitrobenzylthioguanosine (1–10 μmol/l), nitrobenzylthioinosine (0.1–5 μmol/l), and hexobendine (1–100 μmol/l) increased the potency of adenosine (0.1–30 μmol/l) by up to 5-fold but did not potentiate cyclohexyladenosine (0.01–10 μmol/l).
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3.
The benzodiazepine, diazepam (1μmol/l) slightly increased the potency of adenosine (by 1.7-fold) whereas flurazepam (3 μmol/l) had no effect, suggesting that inhibition of adenosine uptake is probably not the major therapeutic action of these compounds.
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4.
The uptake inhibitors depressed the amplitude of the monosynaptic epsp when added alone, an effect reversed by adenosine deaminase (1 unit/ml) whereas the adenosine deaminase inhibitor, erthro-9-(2-hydroxy-3-nonyl)adenine (10 μmol/l) had no effect on adenosine action.
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5.
These results show that in this preparation (a) adenosine action is attenuated by an uptake mechanism and (b) endogenous adenosine release normally has no apparent effects on synaptic transmission at low stimulus rates. Nitrobenzylthioinosine and nitrobenzylthioguanosine are probably the best uptake blockers.
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Sanderson, G., Scholfield, C.N. Effects of adenosine uptake blockers and adenosine on evoked potentials of guinea-pig olfactory cortex. Pflugers Arch. 406, 25–30 (1986). https://doi.org/10.1007/BF00582948
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DOI: https://doi.org/10.1007/BF00582948