Blunted adenosine A2a receptor function in platelets in patients with major depression.

There is provisional evidence of involvement of adenosine in depression. In this study, the second messenger intracellular calcium response in platelets was measured in patients with major depression and controls using spectrofluorometry. The primary result of this study was a statistically significantly blunted second messenger response to agonist stimulation in the depressed group compared to the control group at the 50 and 100 nM and 1 microM dosage levels. This suggests that dysregulation of the adenosine A2a receptor may be present in depression.

Efficacy of mirtazapine add on therapy to haloperidol in the treatment of the negative symptoms of schizophrenia: a double-blind randomized placebo-controlled study.

The negative symptoms of schizophrenia remain a major clinical challenge. Mirtazapine is an antidepressant with antagonist properties at 5-HT2A, 5-HT3 and alpha 2 receptors as well as indirect 5-HT1a agonist effects. Many of these pharmacological actions have clinical or preclinical evidence of efficacy in schizophrenia. This study was a 6-week randomized placebo-controlled trial of mirtzepine or placebo add on to haloperidol 5 mg in the treatment of 30 patients with DSM-IV schizophrenia. The primary finding of the trial was a 42% reduction in Positive and Negative Syndrome Scale (PANSS) negative symptom scores in the mirtazapine group compared to placebo at the end of 6 weeks (mirtazapine 13.9, SD 1.56; placebo 23.9, SD 1.56; P = 0.000, F = 20.31, d.f. = 1). The PANNS total scores, Clinical Global Impression severity and improvement scales in addition showed superiority of mirtazapine over placebo. There was no difference between the groups on the Hamilton depression scale at endpoint, suggesting that the improvement in negative symptoms was not an artifact of mood improvement. These results suggest a potential role for mirtazapine in the negative symptoms of schizophrenia.