Review of clinical studies with mianserin

Pharmacology and behavioral pharmacology of the mesocortical dopamine system

The prefrontal cortex (PFC) has long been known to be involved in the mediation of complex behavioral responses. Considerable research efforts are directed towards refining the knowledge about the function of this brain area and the role it plays in cognitive performance and behavioral output. In the first part, this review provides, from a pharmacological perspective, an overview of anatomical, electrophysiological and neurochemical aspects of the function of the PFC, with an emphasis on the mesocortical dopamine system. Anatomy of the mesocortical system, basic physiological and pharmacological properties of neurotransmission within the PFC, and interactions between dopamine and glutamate as well as other transmitters within the mesocorticolimbic circuit are included. The coverage of these data is largely restricted to what is relevant for the second part of the review which focuses on behavioral studies that have examined the role of the PFC in a variety of phenomena, behaviors and paradigms. These include reward and addiction, locomotor activity and sensitization, learning, cognition, and schizophrenia. Although the focus of this review is on the mesocortical dopamine system, given the intricate interactions of dopamine with other transmitter systems within the PFC and the importance of the PFC as a source of glutamate in subcortical areas, these aspects are also covered in some detail where appropriate. Naturally, a topic as complex as this cannot be covered comprehensively in its entirety. Therefore this review is largely limited to data derived from studies using rats, and it is also specifically restricted to data concerning the medial PFC (mPFC). Since in several fields of research the findings concerning the function or role of the mPFC are relatively inconsistent, the question is addressed whether these inconsistencies might, at least in part, be related to the anatomical and functional heterogeneity of this brain area.

Fenfluramine challenge test predicts outcome in pharmacological treatment of patients with functional gastrointestinal disorder

We investigated if response to the fenfluramine challenge test could predict outcome in 47 nonpsychiatric patients with chronic functional gastrointestinal disorder (FGD) treated with mianserin, a drug closely related to mirtazepine, or placebo. Sixty milligrams of fenfluramine was given orally in the morning on nonfasting basis. Serum cortisol (COR) and prolactin (PRL) were analyzed at baseline, and after 120, 180, and 240 minutes. Patients were then randomized into a 7-week double-blind treatment trial with mianserin or placebo. Response to treatment with mianserin (76% vs.18% for placebo) was closely linked to a high increase in PRL and COR following a fenfluramine challenge test (positive predictive power=72%). Adding length of illness history increased both positive and negative predictive power to 92%. Our results indicate that the fenfluramine challenge test may be a potentially useful tool to identify nonpsychiatric subjects with FGD, who will most likely respond to treatment with a combined alpha2 and 5HT-2 and -3 antagonist.

Idazoxan preferentially increases dopamine output in the rat medial prefrontal cortex at the nerve terminal level

The effects of the alpha2-adrenoceptor antagonist idazoxan on extracellular concentrations of dopamine in major dopaminergic terminal regions in the brain were investigated by means of microdialysis in freely moving rats. Systemic administration of idazoxan markedly increased dopamine output in the medial prefrontal cortex, whereas it failed to affect dopamine efflux in the striatum or in the nucleus accumbens. Local perfusion of idazoxan via reversed dialysis markedly enhanced dopamine efflux in cortical but not subcortical areas, in which dopamine output was but little affected. Infusion of idazoxan into the ventral tegmental area did not alter the dopamine efflux in the medial prefrontal cortex. Moreover, the increase in cortical dopamine efflux induced by systemic administration of idazoxan was unaffected by tetrodotoxin perfusion of the ventral tegmental area. These data show that the alpha2-adrenoceptor antagonist idazoxan preferentially increases basal dopamine output in the medial prefrontal cortex through a local mechanism, an effect which appears largely independent of dopaminergic neuronal activity. An enhanced output of cortical dopamine may contribute to the purported augmentation by alpha2-adrenoceptor antagonists of the therapeutic effects of both antidepressant and antipsychotic drugs.

What has happened to the new antidepressant drugs?

Depression is a widespread and serious disease for which a multiplicity of antidepressant drugs is available for treatment. Although these agents are numerous, there is little to distinguish among them except for their different side-effects. This article reviews the antidepressant drugs that currently are available in Australia, the antidepressant drugs that are used in other countries and some antidepressant drugs that are likely to become available internationally in the next few years.

Efficacy and safety of mianserin in the treatment of depression of women with cancer

Depression is a major complication of cancer. The efficacy and safety of mianserin were evaluated in a randomized placebo-controlled trial of 73 depressed women with cancer. According to RDC diagnosis, all patients showed situational major depression. Both groups were well matched for cancer localization, clinical stages, Karnofsky scores, duration of depression, baseline values on the Hamilton Depression Rating Scale (HDRS), Zung Self-Rating Depression Scale (ZSRDS), and Clinical Global Impression of Illness Severity (CGI-S), and for type of depression, whether dominantly depressive or depressive-anxious. Between days 7-21, there were significantly fewer dropouts with mianserin (7) than with placebo (15). When compared with placebo, there were significant improvements for mianserin for HDRS on days 7, 21 and 28, for ZSRDS on days 7 and 28, and for CGI-S on days 7, 14, 21 and 28. According to Clinical Global Impression of Illness Improvement (CGI-I) there were significantly more responders with mianserin (28) than with placebo (18). The efficacy index for mianserin was significantly greater than for placebo on days 21 and 28. At the end of the trial the scores for HDRS sleep disturbance factor and HDRS anxiety-somatization factor were significantly reduced for mianserin than for placebo. There were no significant differences in side-effects between treatment groups. It is concluded that mianserin is superior to placebo in reducing the severity and duration of depression which is present especially in patients with advanced cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

A double-blind group comparative study using the new anti-depressant Org 3770, placebo and diazepam in patients with expected insomnia and anxiety before elective gynaecological surgery

Two hundred and fifty female patients about to undergo elective gynaecological surgery, were randomly allocated to a single oral dose of either 5, 15, 30 mg Org 3770, placebo, or 10 mg diazepam the evening before operation. Assessment of sleep quality next morning using self-rated questionnaires showed that both Org 3770 and diazepam were significantly better than placebo in enhancing sleep. In addition, a dose-response effect was seen with Org 3770, 15 mg seeming optimal. Assessment of presurgery anxiety, again using self-rated questionnaires, showed that 15 mg Org 3770, and 10 mg diazepam were significantly more effective than placebo at reducing anxiety. None of the medications produced any troublesome side effects nor did they have an effect on blood pressure.