Upregulation of A1 adenosine receptors in human temporal lobe epilepsy: a quantitative autoradiographic study.

A significant increase of A1 adenosine receptor binding (48% increase of mean) was detected in human neocortex obtained from patients suffering from temporal lobe epilepsy as compared to control neocortex from non-epileptic patients. Such increase was equally distributed in the six cortical layers and reached similar levels in each of the five specimens tested independently of age, sex and pharmacological treatment of the patient. Since adenosine exerts a depressant effect on neocortical neurons in slices obtained from epileptic patients, this upregulation of A1 receptor binding may constitute a protective mechanism against subsequent seizures, which is exerted by elevating the depressant response of the brain to endogenous adenosine.