[¹¹C]raclopride positron emission tomography study of dopamine‐D_2/3 receptor binding in patients with severe major depressive episodes before and after electroconvulsive therapy and compared to control subjects

Abstract

Aim The aim of the study was to test: (i) if D2/D3 binding in three functional subsections of striatum is different in patients with severe major depressive episodes than in controls; and (ii) if this difference is normalized after electroconvulsive therapy (ECT). Methods Nine inpatients were examined with positron emission tomography (PET) and the radioligand [11C]raclopride before and after an average of 8.4 ECT sessions. Treatment response was assessed using the Montgomery–Åsberg Depression Rating Scale. Nine age‐ and sex‐matched controls were examined twice with PET and [11C]raclopride. Results [11C]raclopride binding was significantly lower in all three subsections of striatum in patients compared to controls (Cohen's dz, 1.14–1.68; P = 0.003–0.027). Montgomery–Åsberg Depression Ratings decreased significantly after ECT (P < 0.001; Cohen's dz, 2.9). ECT had no statistically significant effect on [11C]raclopride binding, although post‐ECT binding estimates were more similar to those obtained in controls in all subsections of striatum. Conclusion Using PET and [11C]raclopride, we found support for the notion that severe major depressive episodes are associated with significantly lower dopamine D2/D3 binding in all three subsections of striatum compared to controls. We noted no significant effect on D2/D3 binding in the patient group after response to ECT.

The utility of PET imaging in depression

“…Similarly, a different PET study using [ 11 C]raclopride (a selective dopamine D2/D3 antagonist tracer) found patients experiencing major depressive episodes had lower dopamine D2/D3 binding in the striatum compared to those who did not have depression. However, in this study, ECT did not result in a significant improvement in D2/D3 binding in patients with depression ( 84 ).…”

A randomized placebo-controlled PET study of ketamine´s effect on serotonin1B receptor binding in patients with SSRI-resistant depression

“…VST is a core structure in the reward system and dopamine a major mediator of reward related behavior. Impaired reward reversal learning has indeed been demonstrated in MDD patients, along with reduced striatal activity during unexpected rewards and dopamine dysregulation 46,47 . Ketamine increases dopamine levels in the VST in rodents, even though ketamine-induced dopamine release appears less pronounced in humans 22 .…”

Current progress in neuroimaging research for the treatment of major depression with electroconvulsive therapy

“…Combined with the patient’s clinical response, it has been proven that the dopamine nervous system is part of the mechanism of ECT. Tiger et al [ 34 ] used PET and [ 11 C]raclopride to examine patients with severe MDD before and after ECT, and healthy controls. Compared with the control group, the [ 11 C]raclopride binding rate in all three parts of the striatum decreased significantly in the patients.…”