Electroconvulsive shock: progressive dopamine autoreceptor subsensitivity independent of repeated treatment.

Repeated electroconvulsive shock, applied to rats, induces a subsensitivity of dopamine autoreceptors located in the substantia nigra as indexed by single-unit electrophysiological techniques. This reduced sensitivity is time-dependent, since effects similar to those seen with repeated treatment were also observed when single electroconvulsive shock was followed by an appropriate treatment-free interval. These data, coupled with identical results after the repeated administration of tricyclic antidepressants, raise the possibility that a reduction of dopamine autoreceptor sensitivity could underlie both electroconvulsive shock and pharmacological treatment of depression.