These results suggest a necessary role for the D3R in EtOH but not AMPH sensitization, possibly through postreceptor intracellular mechanisms. Results also suggest that different neurochemical mechanisms underlie sensitization to different drugs of abuse.

Results suggest a modulatory role for the D3R in behavioural sensitization to EtOH, where D3R blockade is associated with induction and D3R stimulation is associated with expression of EtOH sensitization. A model is suggested to account for these complementary functions of the D3R at different stages of EtOH sensitization.

Objective-To investigate the effects of light therapy on serotonin transporter binding (5-HTT BP ND ), an index of 5-HTT levels, in the anterior cingulate and prefrontal cortices (ACC and PFC) of healthy individuals during the fall and winter. Twenty-five per cent of healthy individuals experience seasonal mood changes that affect functioning. 5-HTT BP ND has been found to be higher across multiple brain regions in the fall and winter relative to spring and summer, and elevated 5-HTT BP ND may lead to extracellular serotonin loss and low mood. We hypothesized that, during the fall and winter, light therapy would reduce 5-HTT BP ND in the ACC and PFC, which sample brain regions involved in mood regulation.Method-In a single-blind, placebo-controlled, counterbalanced, crossover design, [ 11 C]DASB positron emission tomography was used measure 5-HTT BP ND following light therapy and placebo conditions during fall and winter.Results-In winter, light therapy significantly decreased 5-HTT BP ND by 12% in the ACC relative to placebo (F 1,9 = 18.04, P = 0.002). In the fall, no significant change in 5-HTT BP ND was found in any region across conditions.