SUBSENSITIVITY OF CATECHOLAMINERGIC NEURONS TO DIRECT ACTING AGONISTS AFTER SINGLE OR REPEATED ELECTROCONVULSIVE SHOCK

  • 1 January 1982
    • journal article
    • research article
    • Vol. 17  (10) , 1059-1070
Abstract
Spontaneous firing rates and changes in firing rate in response to an i.v. administered dose of apomorphine were measured after various electroconvulsive shock (ECS) treatment regimens from dopaminergic cells of the substantia nigra in urethane-anesthetized rats. Similar measurements were obtained from noradrenergic neurons of the locus coeruleus before and after i.v. injection of clonidine. A significant decrement in the inhibition of spontaneous firing in response to i.v. administration in these agonists was observed following multiple or single ECS treatment in both substantia nigra and locus coeruleus cells. There was a consistent but nonsignificant tendency for cells in both areas of the brain from treated animals to display higher rates of spontaneous firing than their respective sham-shocked controls. Both the effects on baseline rates of spontaneous activity and on the depression of firing rate in response to drug administration were independent of repeated treatment. A significant negative correlation was obtained between baseline firing rate and percentage depression to the autoreceptor agonist, but this correlation alone was insufficient to account for the observed differences in the drug response. Possible mechanisms of action of electroconvulsive therapy in the treatment of depression are discussed.