Physiological modulation by adenosine: selective blockade of A1-receptors with DPCPX enhances stimulus train-evoked neuronal Ca influx in rat hippocampal slices.
Decreases in the extracellular Ca2+ concentration (delta Ca) elicited by a 20 Hz/10 s orthodromic stimulus train were measured with combined ion sensitive/recording electrodes in the CA1 area of rat hippocampal slices. Addition of the selective adenosine A1-receptor antagonist, DPCPX, or adenosine deaminase increased evoked delta Ca in the synaptic and pyramidal cell soma layer by more than 100%. This was accompanied by an earlier generation of population spikes during the train. It is concluded that physiological adenosine concentrations of about 1 microM exert a depressive tonus on synaptic transmission and frequency potentiation and that this effect is mediated via A1-receptors.
Schubert
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Max Planck Institute for Psychiatry, Department of Neuromorphology, Martinsried, F.R.G.
D000243:Adenosine Deaminase / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004558:Electric Stimulation; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011712:Pyramidal Tracts / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011983:Receptors, Purinergic / Q000187:drug effects / Q000502:physiology*; D014970:Xanthines / Q000494:pharmacology*
D011983:Receptors, Purinergic; D014970:Xanthines; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000243:Adenosine Deaminase; D002118:Calcium