Comparison of the effects of repeated electroconvulsive shock on alpha 2- and beta-adrenoceptors in different regions of rat brain

The effects of ten, once-daily electroconvulsive shocks on alpha 2 and beta-adrenoceptor binding were investigated in the rat cortex, hippocampus, hypothalamus and cerebellum. [3H]Clonidine and [3H]dihydroalprenolol were used as radioligands for alpha 2 and beta-adrenoceptors respectively. Twenty-four hours after the last shock, the density of beta-adrenoceptors was reduced in the cortex and hippocampus, but not in the hypothalamus or cerebellum. There was no change in the apparent affinity of the beta-receptors in any of the regions studied. Alpha 2-adrenoceptor density was reduced in all the regions studied (cortex, hippocampus, hypothalamus) with, again, no change in their apparent affinity. It is concluded that the effects of electro-convulsive shock on alpha 2 and beta-adrenoceptors show regional variation; possible reasons for this variation are discussed.