The relation between striatal dopamine D2/D3 receptor availability and sleep quality in healthy adults

Increasing evidence, primarily from animal studies and patients with compromised neurotransmitter systems, indicates a possibly important role for dopamine in modulating sleep. We therefore conducted this study to explore the relation between sleep and dopamine in healthy adults.

We used the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. Higher PSQI scores indicate a lower quality of sleep. Striatal dopamine D2/D3 receptor availability was determined using [123I]iodo-benzamide (IBZM) SPECT. Fifty-five healthy volunteers (32 men, 23 women; mean age, 36.7+/-12.1 years), including 25 good sleepers and 30 poor sleepers, were recruited. We analysed the correlation between the PSQI and D2/D3 receptor availability in good and poor sleepers based on Pearson's product-moment after removing the effects of gender and age. We also analysed differences in D2/D3 receptor availability between good and poor sleepers.

In poor sleepers, there was no statistically significant relationship between the global, individual components of the PSQI score and D2/D3 receptor availability. However, in good sleepers, the score of the sleep duration component was significantly negatively correlated with D2/D3 receptor availability in the caudate. There was no significant difference in D2/D3 receptor availability between good and poor sleepers.

Our findings demonstrate that healthy good sleepers with higher D2/D3 receptor availability in the caudate sleep longer. Poor sleep in healthy subjects might be not primarily related to the dopaminergic system.