B. Heßelmann

The citalopram challenge test in patients with major depression and in healthy controls

Neuroendocrine challenge tests in depressed patients have revealed a blunted hormonal reaction to serotonergic stimuli. In the present study, citalopram was chosen as the serotonergic agent for neuroendocrine stimulation. Compared to earlier challenge agents, citalopram has the advantage of serotonergic selectivity, its application is well tolerated and the possibility of intravenous application reduces pharmacokinetic interference. Sixteen patients suffering from an acute episode of major depression and 16 healthy controls underwent the stimulation procedure with 20 mg of citalopram and placebo. Whereas significant differences in the secretion of prolactin and cortisol between citalopram and placebo challenge were observed in the control group, no differences were found in the group of depressed patients. Comparison of depressed patients and controls showed a significantly blunted prolactin secretion in patients. Differences in cortisol secretion following serotonergic stimulation with citalopram did not become significant. The stimulation procedure was well tolerated in all subjects, although a higher number of side effects was observed in the control group. The amount of side effects did not correlate with the hormone responses. These results are in line with the hypothesis of serotonergic hypofunction in depressed patients. In conclusion, the 20-mg citalopram challenge test is thought to be a promising tool for further investigation of serotonergic function in psychiatric illness.

Sertindole and dopamine D2 receptor occupancy in comparison to risperidone, clozapine and haloperidol – a 123I-IBZM SPECT study

Abstract The striatal D2 dopamine binding was studied in schizophrenic patients treated with the novel atypical antipsychotic drug sertindole (n = 10). Comparisons were obtained with haloperidol (n = 8), clozapine (n = 6), risperidone (n = 11) and untreated healthy controls (n = 8) of a dataset which has partly been reported previously. 123I-Iodobenzamide (IBZM) single photon emission computerized tomography (SPECT) was used for estimation of striatal dopamine D2 receptor binding. Sertindole-treated patients exhibited significantly (P < 0.001) lower levels of striatal D2 binding (BG/FC ratio:1.28) compared with those treated with haloperidol (BG/FC ratio:1.09) and risperidone (8 mg:1.18) but significantly (P < 0.005) higher levels compared with clozapine (BG/FC ratio:1.49). However, if patients were pretreated with a depot neuroleptic, significantly (P < 0.05) higher striatal D2 binding (BG/FC ratio:1.12) has been obtained. Since sertindole has been shown to exert distinct clinical efficacy for treatment of positive and negative symptoms, our data are indicative that antipsychotic efficacy is not associated with a high degree of striatal D2 receptor occupancy in schizophrenic patients.

Metabolismustheorie des therapeutischen Schlafentzugs

Unter den verschiedenen Wirkmechanismen, die fur den antidepressiven Effekt des therapeutischen Schlafentzugs (SE) verantwortlich gemacht werden, wird auch diskutiert, das eine Veranderung von Neurotransmittern, bzw. die von diesen beeinflusten Hormone von pathophysiologischer Bedeutung sind. An hormonellen Parametern wurden zum einen die der Hypothalamus-Hypophysen-Schilddrusenachse und zum anderen die der Hypothalamus-Hypophysen-Nebennierenrindenachse mit der Bestimmung der daraus ableitbaren Hormone (TSH, T3, T4, ACTH, Cortisol) untersucht. Weiterhin wurden Basalwertmessungen von Melatonin und Prolaktin, sowie Stimulations- bzw. Hemmtests mit dem TRH-Test, Dexamethason-Hemmtest und dem Fenfluramin-Stimulationstest durchgefuhrt. In Verbindung mit hormonellen Parametern wird auch die charakteristische Veranderung der Korperkerntemperatur diskutiert (zur Ubersicht: Kasper et al. 1989).