Abstract
Subcutaneous apomorphine, a dopaminergic agonist, is used as a neuroendocrine probe for assessing central dopaminergic activity. The aim of our study was to test sublingual apomorphine for the same purpose.
We administered sublingual apomorphine in a weight-dependent dose (0.033 mg/kg) to 42 healthy men. Prolactin and growth hormone levels were measured before and after the administration at 15, 30, 45, 60, 75, 90, 120, 150 and 180 min.
Subjects filled in Zung's self-assessment scores of anxiety (SAS) and depression (SDS) questionnaires before and after the test. Areas under the curve for prolactin and growth hormone levels were calculated using the trapezoidal rule.
All subjects showed decreased prolactin, and 40/42 subjects showed increased growth hormone, in response to sublingual apomorphine. Average peak value for prolactin was -4.6 +/- 1.8 mu g/l.
Average peak value for growth hormone was 8.1 +/- 8.5 ng/ml for the whole group, and 9.6 +/- 8.1 ng/ml after exclusion of two negative growth hormone responders. Sublingual apomorphine produced no major side effects.
Significant decreases in SAS (21.5 +/- 5.7 vs. 20.6 +/- 5.5) and SDS (9.7 +/- 7.8 vs. 7.8 +/- 6.8) scores were observed after the test. Sublingually administered apomorphine appears to be well tolerated and useful as a neuroendocrine marker of central dopaminergic activity.