1. Epileptogenic actions of xanthines in relation to their affinities for adenosine A1 receptors in CA3 neurons of hippocampal slices (guinea pig)
- Author
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Isaak Moraidis and Dieter Bingmann
- Subjects
medicine.medical_specialty ,Adenosine ,Guinea Pigs ,In Vitro Techniques ,Biology ,Inhibitory postsynaptic potential ,Hippocampus ,Membrane Potentials ,Adenosine A1 receptor ,chemistry.chemical_compound ,Caffeine ,Internal medicine ,Calcium flux ,Cyclic AMP ,medicine ,Animals ,Magnesium ,Molecular Biology ,Neurons ,Epilepsy ,Paroxysmal depolarizing shift ,General Neuroscience ,Receptors, Purinergic P1 ,Purinergic signalling ,Adenosine receptor ,Endocrinology ,Purinergic P1 Receptor Antagonists ,chemistry ,Xanthines ,Phenylisopropyladenosine ,Calcium ,Neurology (clinical) ,Developmental Biology ,medicine.drug - Abstract
In order to analyze the epileptogenic mechanisms of caffeine and related xanthines, putative effects of these drugs were studied on adenosine receptors of CA3 neurons in hippocampal slices. Epileptogenic concentrations of different xanthine derivatives strongly correlated with their affinities for the inhibitory A1 adenosine receptor subtype. The A1 receptor agonists adenosine and R-PIA reversibly depressed xanthine-induced epileptic activity without effects on the resting membrane potential or on spontaneously occurring action potentials. These findings suggest that the epileptogenic potency of xanthines is primarily due to the blockade of the A1 receptors through an abnormal rise of intracellular cAMP and to the excessive transmembrane calcium fluxes underlying paroxysmal depolarization shifts.
- Published
- 1994
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