α‐1 Adrenoceptors are decreased in human epileptic foci

Abstract

Cortical α‐1 adrenoceptors were measured in tissues obtained from 10 patients immediately following temporal lobectomy for intractable partial epilepsy. At operation each patient exhibited spontaneous spiking restricted to either the anterior (n = 5) or posterior (n = 5) portion of the first two temporal gyri. Control samples were obtained from the nonspiking half of the same gyrus. Receptor‐binding assays were performed on isolated cortical membranes using [³H]prazosin. There was a reduction (p < 0.01) in the receptor density (β_max) of the sites in the epileptic foci without any change in affinity (mean ± SEM): spiking—β_max, 160.5 ± 11.3 fmol/mg protein; affinity, 0.17 ± 0.04 nM; nonspiking—β_max, 218.8 ± 15.6 fmol/mg protein; affinity 0.17 ± 0.04 nM. This relative decrease in α‐1 adrenoceptor density may be the substratum of a noradrenergic hyposensitivity that could contribute to a localized diminution in inhibitory mechanisms in epileptic foci.