Specific norepinephrine and serotonin uptake inhibitors in man: a crossover study with pharmacokinetic, biochemical, neuroendocrine and behavioral parameters

Persistent injury-associated anemia and aging: Novel insights

BACKGROUND

Hypercatecholaminemia and bone marrow dysfunction have been implicated in the pathophysiology of persistent injury-associated anemia. The elderly may be more vulnerable to bone marrow dysfunction due to high basal and peak catecholamine levels and impaired hematopoietic progenitor growth. We hypothesized that aging would adversely affect persistent injury-associated anemia.

METHODS

Male Sprague-Dawley rats aged 8 to 9 weeks and F344-BN rats aged 25 months were randomized to naive controls, lung contusion plus hemorrhagic shock (LCHS), and LCHS plus daily chronic restraint stress (LCHS/CS). Urine norepinephrine was measured on Days 1 and 7. Mobilization of hematopoietic progenitor cells (HPCs), bone marrow colony-forming units-erythroid growth, and peripheral blood hemoglobin, mean corpuscular volume (MCV), and red cell distribution width (RDW) were assessed on Day 7 (*p < 0.05 young vs. aged counterpart by one-way analysis of variance).

RESULTS

Aged rats had higher norepinephrine levels at naive baseline (97* vs. 27 ng/mL) and 7 days following LCHS/CS when compared with young (359* vs. 127 ng/mL). Following LCHS/CS, HPC mobilization was greater among young rats when compared with aged (5.4 vs. 2.5%). Colony-forming units-erythroid growth was lower among aged animals for each group (naive: 47* vs. 65; LCHS: 40* vs. 50; LCHS/CS: 38* vs. 44 cells/plate). Aged naive rats had higher initial hemoglobin (15.2* vs. 14.3 g/dL) but lower MCV (48* vs. 59 fL/cell) and larger RDW at baseline and greater differences 7 days after LCHS/CS (MCV: 46* vs. 60 fL/cell; RDW: 17.4* vs. 16.3%).

CONCLUSIONS

Compared with young rats, aged rats had less HPC mobilization despite elevated basal and peak norepinephrine. Aged rats were disproportionately affected by impaired hematopoietic progenitor growth and an iron-restricted red blood cell phenotype at baseline, which persisted 7 days after injury. Further research is needed to assess how the clinical approach to persistent injury-associated anemia should differ for elderly trauma patients.

Dual serotonin and noradrenaline uptake inhibitor class of antidepressants potential for greater efficacy or just hype?

Preclinical and clinical studies support the rationale that development of single molecules, which would promote serotonergic and noradrenergic neurotransmission by inhibiting simultaneously the uptake of both monoamines, would potentially result in improved antidepressant drugs. Currently, the dual inhibitors of serotonin and noradrenaline uptake are venlafaxine, milnacipran and duloxetine. Based on the preclinical studies, the three drugs do show properties of inhibiting uptake of both monoamines in vitro and in vivo in the following order of decreasing potency: duloxetine, venlafaxine and milnacipran, and all exhibit low affinity at neuronal receptors of neurotransmitters, suggesting low side-effect potential. In double-blind, controlled studies, venlafaxine and milnacipran were repeatedly shown to be as efficacious as tricyclic antidepressant drugs in treating major depressive disorder, while one double-blind, placebo-controlled trial showed the antidepressant efficacy of duloxetine. Specifically designed comparative trials of dual uptake inhibitors against the other agents are needed to establish whether the dual uptake inhibitors show improvement in efficacy, rate of responders, antidepressive effects and/or remission.

Effects of chronic antidepressant drug administration and electroconvulsive shock on locus coeruleus electrophysiologic activity

BACKGROUND

The locus coeruleus (LC) is the major noradrenergic cell body group in the brain. Although previous studies have examined changes in electrophysiologic activity of LC neurons produced by antidepressant drugs, only a small number have examined changes that occur with chronic drug administration, which is the therapeutically effective regimen, and only one group of investigators has assessed effects on activated (or "burst") firing of LC neurons under such treatment conditions. The present study assessed changes produced in rats by effective antidepressant treatments-several drugs given chronically (two tricyclic antidepressants, two selective serotonin reuptake inhibitors, and a monoamine oxidase inhibitor) as well as a series of electroconvulsive shocks (ECSs)-in single-unit electrophysiologic activity of LC neurons, measuring effects on spontaneous depolarization rate and also on sensory-evoked burst firing.

METHODS

Drugs were administered via osmotic minipumps for either 14 or 30 days; ECSs were administered five times, with a 72-hour interval between each administration. Electrophysiologic recording of LC activity took place under halothane anesthesia on the last day of drug treatment or following a delay of 1 or 5 days after the final ECS.

RESULTS

A common effect of all drugs tested and ECS treatment was to decrease LC spontaneous and sensory-evoked burst firing.

CONCLUSIONS

The clinical efficacy of antidepressant medication and ECS may be mediated, in part, through reduction of LC neural activity. The findings reported here are consistent with recent indications that LC neurons are hyperactive in depressed individuals and with suggestions that some behavioral changes seen in depression can arise from consequences of rapidly depolarizing LC terminals, such as release of peptides.

Catecholamines in depression: a cumulative study of urinary norepinephrine and its major metabolites in unipolar and bipolar depressed patients versus healthy volunteers at the NIMH

Studies comparing urinary norepinephrine (NE) and its metabolites in unipolar or bipolar depressed patients and healthy volunteers have not yielded consistent findings. However, in unipolar depressed patients, most studies in non-elderly populations consistently report elevated concentrations of plasma NE, at least following an orthostatic challenge. Expanding upon previous studies which showed elevated plasma NE in depression, we compared the urinary excretion of NE, normetanephrine (NMN), 3-methoxy-4-hydroxyphenylglycol (MHPG), and vanillylmandelic acid (VMA) in age- and sex-matched unipolar and bipolar depressed patients versus healthy volunteers hospitalized at an inpatient unit at the National Institute of Mental Health. Only depressed subjects with a minimum 4-week drug-free period were included. Total turnover (NE + NMN + MHPG + VMA) was reduced in this sample of unipolar and bipolar depressed patients. MHPG concentration did not distinguish unipolar from bipolar depressed patients and was not significantly different from that in healthy volunteers. A construct of the average fractional extraneuronal concentration of NE (NE + NMN/NE + NMN + MHPG + VMA) was significantly higher in unipolar and bipolar depressed patients than in healthy volunteers. This finding extends data suggesting that unmedicated unipolar and bipolar depressed patients have a 'hyperresponsive' noradrenergic system and provides a framework which ties together plasma and urinary findings.

Circadian rhythms and the pharmacology of affective illness

The chronic effects of antidepressant drugs (ADs) on circadian rhythms of behavior, physiology and endocrinology are reviewed. The timekeeping properties of several classes of ADs, including tricyclic antidepressants, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, serotonin agonists and antagonists, benzodiazepines, and melatonin are reviewed. Pharmacological effects on the circadian amplitude and phase, as well as effects on day-night measurements of motor activity, sleep-wake, body temperature (Tb), 3-methoxy-4-hydroxyphenylglycol, cortisol, thyroid hormone, prolactin, growth hormone and melatonin are examined. ADs often lower nocturnal Tb and affect the homeostatic regulation of sleep. ADs often advance the timing and decrease the amount of slow wave sleep, reduce rapid eye movement sleep and increase or decrease arousal. Together, AD effects on nocturnal Tb and sleep may be related to their therapeutic properties. ADs sometimes delay nocturnal cortisol timing and increase nocturnal melatonin, thyroid hormone and prolactin levels; these effects often vary with diagnosis, and clinical state. The effects of ADs on the coupling of the central circadian pacemaker to photic and nonphotic zeitgebers are discussed.

Changes in the regulation of 5-hydroxytryptamine release by alpha2-adrenoceptors in the rat hippocampus after long-term desipramine treatment

In vivo microdialysis was used to measure the effects of long-term treatment of rats with desipramine upon the regulation by alpha2-adrenoceptors of serotonin (5-hydroxytryptamine, 5-HT) release from the serotonergic neurons in the hippocampus. Rats were injected with saline or desipramine, 10 mg/kg, i.p., every 12 h for 14 days. When added to the perfusion solution, brimonidine, an alpha2-adrenoceptor agonist, significantly inhibited the K+-evoked release of 5-HT in the hippocampi of saline-treated, control rats. This action of brimonidine was prevented by pretreating the rats with idazoxan, an alpha2-adrenoceptor antagonist. Long-term desipramine treatment significantly reduced the inhibitory effect of brimonidine upon the K+-evoked 5-HT release. With long-term administration of desipramine, noradrenaline content in the hippocampi was significantly decreased as compared with that of the control rats, whereas the basal noradrenaline concentration in the dialysate was significantly increased. On the other hand, both the 5-HT content of the hippocampus and the basal 5-HT concentration in the dialysate were significantly increased. The present study suggests that long-term administration of desipramine causes a functional subsensitivity of the presynaptic alpha2-adrenoceptors that regulate serotonergic neuronal function in the rat hippocampus. It also supports the concept that changes in the sensitivity of alpha2-adrenoceptors that regulate neurotransmitter release play an important role in the mechanism of antidepressant drug action.

Effect of fluvoxamine, imipramine and placebo on catecholamine function in depressed outpatients

Many of the specific serotonin reuptake inhibitors appear to have some effect on noradrenergic function. Fluvoxamine is one of the newer agents and its specificity has not been fully assessed. Depressed patients participating in a study comparing the efficacy of fluvoxamine with imipramine and placebo collected 24 hour urine samples (N = 38) and had plasma samples drawn (N = 38) prior to and after 6 weeks of double blind treatment. Urine samples were analyzed for 24 hour output of MHPG, VMA, NMN, MN and HVA. Plasma samples were analyzed for NE levels. Imipramine treatment produced a reduction in urinary MHPG, an increase in the ratio of NMN to MHPG plus VMA, and a trend towards an increase in plasma NE which was significantly different than the effects seen in the fluvoxamine and placebo groups. There was an additional finding in the imipramine group of a significant correlation between percentage change in plasma NE and clinical improvement. Fluvoxamine treatment, on the other hand, produced no clear effect on any measure of noradrenergic function and the antidepressant efficacy of fluvoxamine was unrelated to any noradrenergic variable. These findings lend support to the hypothesis that fluvoxamine does not have significant effects on noradrenergic function.

Biogenic amines and their metabolites in body fluids of normal, psychiatric and neurological subjects

The biogenic monoamines and their metabolites have been isolated, identified and quantified in human body fluids over the past forty years using a wide variety of chromatographic separation and detection techniques. This review summarizes the results of those studies on normal, psychiatric and neurological subjects. Tables of normal values and the methods used to obtain them should prove to be useful as a reference source for benchmark amine and metabolite concentrations and for successful analytical procedures for their chromatographic separation, detection and quantification. Summaries of the often contradictory results of the application of these methods to psychiatric and neurological problems are presented and may assist in the assessment of the validity of the results of experiments in this field. Finally, the individual, environmental and the methodological factors affecting the concentrations of the amines and their metabolites are discussed.

Treatment strategy in depression. I. Non-tricyclic and selective reuptake inhibitors in resistant depression: a double-blind partial crossover study on the effects of oxaprotiline and fluvoxamine

Antidepressants are ineffective in about 30% of patients with major depression. Some authors then advise treatment of non-responders with (non-tricyclic) more selective reuptake inhibitors. In a double-blind, partial crossover study, 71 patients were selected for treatment during 4 weeks with oxaprotiline and/or fluvoxamine, two non-tricyclic antidepressants that are selective reuptake inhibitors or noradrenaline and serotonin respectively. All patients had failed to respond to earlier treatment with cyclic antidepressants during the current episode. Only 13% of the patients responded, with 27% of them responding to oxaprotiline and none to fluvoxamine. Moreover, a low response of 27% was also obtained in the crossover phase, which included all non-responders to the first treatment, oxaprotiline being effective in 39% and fluvoxamine in 10% of the patients. The results indicate that selective reuptake inhibitors are not an effective alternative for non-responders to other cyclic antidepressants and that non-responders to "noradrenergic" antidepressants do not appear to have much chance of responding to "serotonergic" antidepressants and vice versa.

The effects of desipramine, zimelidine, electroconvulsive treatment and lithium on rat brain biogenic amines: a comparison with peripheral changes

The effects of 4 common treatments for affective disorders on total body norepinephrine (NE) and dopamine (DA) turnover and metabolism were evaluated in rats. The treatments were chronic desipramine (DMI), zimelidine (ZMI), electroconvulsion (ECT) and lithium (Li). The central effects of ECT and Li were also assessed in the brain. The results obtained were compared with the effects of these 4 treatments on total NE (Sum NE) and DA (Sum DA) turnover in depressed patients. We have also evaluated central and/or peripheral effects of these treatments on phenylethylamine, p-tyramine and serotonin metabolism. The urinary changes in Sum NE and DA observed after DMI, ZMI and Li in the rat were similar to those found in depressed patients; Sum NE was significantly reduced. In contrast to its effects on depressed patients, chronic ECT significantly increased Sum NE. Similar to depressed patients, ECT reduced the fraction of NE escaping re-uptake in the rat. Sum DA was not affected by DMI, ZMI or ECT, but was significantly reduced by chronic Li treatment. All 4 treatments significantly reduced serotonin metabolism as indicated by reduced 5-hydroxyindoleacetic acid excretion rates. DMI, ZMI and Li treatments significantly reduced phenylethylamine urinary but not p-tyramine urinary outputs. The opposite effect was observed after ECT. Consistent with their effects on Sum NE, Li reduced while ECT increased hypothalamic NE turnover as deduced from the changes in 3-methoxy-4-hydroxyphenylglycol's rate of formation. As for Sum DA, Li had no effect on 3,4-dihydroxyphenylacetic acid or homovanillic acid's rates of formation in the caudate nucleus. Chronic ECT produced a small, but significant increase in homovanillic acid's rate of formation in the caudate nucleus.

Interacting neurotransmitter systems. A non-experimental approach to the 5HIAA-HVA correlation in human CSF

The repeatedly observed strong positive correlation between 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) in human cerebrospinal fluid (CSF) prompted an investigation to see if conclusions concerning possible interactions between brain serotonin and dopamine turnover could be reached from human CSF concentrations of these acid metabolites. CSF data from patients with depressive disorders diagnosed according to the RDC from Sweden (n = 140) and from the National Institute of Mental Health (n = 35) were used to test structural hypotheses by two statistical approaches--LISREL analysis and logistic regression. Results from both men and women were unequivocal: 5HIAA "controls" HVA, interpretable as a regulatory action of serotonin turnover on dopamine turnover. In women, only 5HIAA was affected by age, height and body size (higher in elderly, short and stout women); no similar relationships were seen in males. The concept of a serotonergic regulation of dopamine turnover was tested on brain punch analyses of serotonin and dopamine and their metabolites in two sets of dogs in a large number of brain areas. Results confirm a facilatory effect of serotonin on indices of dopamine turnover in many brain regions, especially brain stem and hypothalamus. The animal data validate the data analytic approach in humans.

Behavioral, biochemical, and blood pressure responses to alprazolam in healthy subjects: interactions with yohimbine

The effect of single doses of alprazolam (1.5 mg) and yohimbine (30 mg) and alprazolam and yohimbine given together on plasma free 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), cortisol, blood pressure, and subjective behavioral ratings was studied in eight healthy subjects. In comparison to placebo, alprazolam significantly reduced plasma MHPG and cortisol, systolic and diastolic blood pressure, and increased subjective ratings of drowsiness and mellow. Yohimbine and the alprazolam-yohimbine combination significantly increased plasma free MHPG. Concomitant yohimbine administration antagonized the effects of alprazolam on blood pressure and attenuated alprazolam-induced changes in cortisol and subjective ratings. The ability of alprazolam to decrease plasma MHPG and blood pressure contrasts with previously reported effects of diazepam. The implications of the findings of the present investigation to the postulated role of brain noradrenergic function in the etiology of panic anxiety and the therapeutic mechanism of action of antipanic treatment are discussed.

Obsessive-compulsive disorder and serotonin: is there a connection?

Reports of the antiobsessional efficacy of clomipramine have led to a "serotonin hypothesis" of obsessive-compulsive disorder (OCD). To test this hypothesis, 16 outpatients with DSM-III OCD were studied using several measures of serotonergic function. Platelet 3H-imipramine binding and serotonin uptake were not significantly different between the OCD patients and a normal, age-matched control group. The level of the metabolite 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF) was significantly higher in a small cohort of obsessionals compared with healthy volunteers, possibly reflecting increased brain serotonin turnover. In a direct test of the role of serotonin uptake in clomipramine's antiobsessional effects, the serotonin uptake inhibitor zimelidine was compared with the noradrenergic uptake inhibitor desipramine in a double-blind, controlled study. Zimelidine reduced CSF 5-HIAA, but was clinically ineffective in this group. Desipramine had weak but significant clinical effects. Nonresponders to zimelidine or desipramine improved significantly during a subsequent double blind trial of clomipramine. These findings demonstrate that pharmacological blockade of serotonin reuptake alone is not sufficient for an antiobsessional response.

Alaproclate a novel antidepressant? A biochemical and clinical comparison with zimeldine

Clinical and biochemical effects of two selective 5-HT uptake inhibitors, zimeldine and alaproclate, were studied in 24 hospitalized patients with endogenous depression. According to a randomized parallel group design 14 patients were treated with zimeldine and 10 with alaproclate. The dosage of both zimeldine and alaproclate was 200 mg daily. For the evaluation of the clinical effect, Montgomery & Asberg Depression Rating Scale (MADRS) was used. Seven of 14 patients treated with zimeldine and seven of 10 treated with alaproclate improved. 5-HT uptake inhibition in patients' platelets and concentration of amine metabolites (5-HIAA, HVA, HMPG) in CSF were studied before and during treatment. After 3 weeks of treatment with zimeldine 5-HIAA and HMPG in CSF decreased significantly while HVA in CSF increased significantly. Zimeldine produced a significant 5-HT uptake inhibition in platelets. During treatment with alaproclate no significant change in amine metabolites concentration in CSF was found and there were no mean changes on 5-HT uptake inhibition in platelets.

Comparison of effects of desipramine and amitriptyline on EEG sleep of depressed patients

Despite their widespread use, there are few data concerning the effects of tricyclic antidepressants on EEG sleep in depression. The present study documented the effects of desipramine (DMI, n = 17) and amitriptyline (AT, n = 16) upon EEG sleep in hospitalized depressed patients as part of a double-blind protocol involving 28 days of active treatment. Compared to placebo, patients receiving DMI showed somewhat worsened sleep continuity, particularly after 1 week of administration when the dose was 150 mg/day. On the other hand, sleep architecture and REM measures showed a rapid suppression of REM sleep, and then partial tolerance for this effect was observed with continued administration of DMI for 3 weeks. DMI was a more potent suppressor of REM sleep, while AT was more sedative. Based on these differences in effects upon EEG sleep, a discriminant function was derived and resulted in a correct classification of 87.5% of AT cases and 76.5% of DMI cases. These results are discussed in terms of the differences in pharmacological profiles for uptake blockade and anticholinergic potency for these two compounds.

Hormonal responses to zimelidine and desipramine in depressed patients

Plasma prolactin (PRL), growth hormone (GH), luteinizing hormone (LH), and cortisol were repeatedly measured during the morning over a 4-hour period in patients who received single or chronic doses of desipramine (DMI) or zimelidine (ZIM). Preclinical studies had suggested that DMI, an uptake inhibitor specific for norepinephrine, would have different effects than ZIM, a selective serotinin uptake inhibitor. The GH response to DMI was blunted in the depressed patients. Neither DMI nor ZIM produced changes in LH or cortisol. DMI acutely increased plasma PRL, whereas ZIM had an effect only after chronic pretreatment. Chronic DMI but not ZIM increased baseline PRL. The patterns and magnitude of responses raise questions concerning the role of serotonin and norepinephrine in PRL release in man and the applicability of current preclinical models.

The effect of desmethylimipramine on the metabolism of norepinephrine

Eleven normal volunteers were given an acute and two chronic doses of desipramine (DMI). The plasma norepinephrine (NE), 3-methoxy-4-hydroxyphenylglycol (MHPG), and dihydroxyphenylglycol (DHPG) concentrations were measured before and during drug administration. DMI reduced plasma concentrations of MHPG by 13% and DHPG by 17%. After two weeks of drug administration, the MHPG/NE ratio was reduced, and there was a significant negative correlation with the concurrent drug concentration. These results suggest that DMI: (1) reduces the turnover of NE; and (2) diminishes the oxidative deamination of NE. In addition, the drug concentration response relationship indicates that the effects of uptake inhibition may not be maximal until concentrations in the apparent therapeutic range are achieved.

Reduced metabolism and turnover rates of rat brain dopamine, norepinephrine and serotonin by chronic desipramine and zimelidine treatments

As part of of an ongoing effort to compare changes in whole body turnover of catecholamines and serotonin in man with those induced by antidepressants in the rat brain, we have evaluated the chronic effects of desipramine (DMI) and zimelidine (ZMI) on brain catecholamines and serotonin in the rat. The amines and metabolites measured include norepinephrine (NE), dopamine (DA) and their metabolites, 3-methoxy-4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). Three brain areas were analysed; the hypothalamus, caudate nucleus and frontal cortex. Chronic DMI and ZMI reduced hypothalamic MHPG and caudate nucleus DA metabolites, in particular HVA. Both drugs reduced NE and DA turnover rates (estimated after alpha-methyl-p-tyrosine injection) and the rate of MHPG formation in the hypothalamus (estimated after pargyline treatment). They did not change NE turnover rate, but reduced DA turnover rate and rate of HVA formation in the caudate nucleus. Chronic DMI but not ZMI reduced DOPAC rate of formation in the caudate nucleus. Apparently changes in DA turnover and metabolism produced by these antidepressants are better related to changes in HVA than DOPAC concentrations. Similar to their influence on hypothalamic and caudate nucleus catecholamines, both chronic DMI and ZMI produced changes in serotonin concentration in the caudate nucleus and frontal cortex serotonin that suggest a reduction in its turnover rate and metabolism. The reduction in NE turnover in hypothalamus is consistent with the effects of chronic DMI and ZMI on whole body NE turnover observed in man.(ABSTRACT TRUNCATED AT 250 WORDS)

Common mechanism of action of biochemically "specific" antidepressants

NE turnover in depressed patients treated with three drugs which have specifically different primary biochemical effects is compared before and after treatment. Turnover is quantitated as the sum of NE and its major metabolites excreted in the urine using a new mass spectrometric assay. Clorgyline , a MAOI specific for Type A; desipramine, a selective NE uptake inhibitor; and zimelidine, a selective 5HT uptake inhibitor, were used. All three antidepressants, including zimelidine, reduced NE turnover although producing very different effects on the metabolic profile of NE. It remains likely that effects on NE are related to therapeutic effect.

Assessment of the anticholinergic effects of antidepressants in a single-dose cross-over study of salivation and plasma levels

In order to evaluate the anticholinergic effect of antidepressant drugs, 11 healthy volunteers were given single oral doses of reference drug, test drugs or placebo on a double-blind basis at weekly intervals. The doses corresponded to average daily patient medications. Spontaneous whole mouth and parotid salivation, and plasma levels of drug and possible metabolites were measured 2, 6 and 10 h after drug administration. Moderate, statistically significant inhibition of salivation was found when nortriptyline, imipramine-N-oxide and mianserin were given. Less pronounced, but still statistically significant inhibition occurred after ingestion of nomifensine and zimelidine. The zimelidine effect was exclusively due to the metabolite norzimelidine, and the inhibition after imipramine-N-oxide was mainly due to the metabolite imipramine, but imipramine-N-oxide itself also had slight activity. Isocarboxazide and lithium had no effect on salivation. From these results and reported values of pharmacokinetic variables, the average level of anticholinergic activity during long-term treatment may be predicted: for mianserin and (nor-)zimelidine moderate inhibition of salivation, although less pronounced than with nortriptyline; for nomifensine no clinically significant effect; and for imipramine-N-oxide a negligible contribution from the unmetabolized drug.

A multicentre double-blind comparative trial of zimeldine and imipramine in primary major depressive disorders

Zimeldine, a new antidepressant with a selective inhibition of 5-HT reuptake, was compared with imipramine in a double-blind comparative study. The trial was conducted on 95 patients with primary major depressive disorder, of endogenous character. During the 4-week study period clinical efficacy was evaluated by using the Hamilton Depression (HAM-D) scale, Beck's Inventory and global ratings. Zimeldine (100 mg b.d.) was shown to have as good an antidepressive effect as imipramine (50 mg t.d.s.) when evaluated on the HAM-D scale. Assessment of the symptom improvement on this rating scale suggested that zimeldine was more effective in improving the patient's insight of the disease. There was no significant difference between zimeldine and imipramine as assessed by a final global improvement rating scale as well as by the patient's own impression. Exploratory data analysis revealed that zimeldine was significantly more effective than imipramine in the following groups; patients over 40 years of age; patients whose initial onset of illness occurred at over 40 years; patients with a history of at least three episodes of depressive illness; patients with mild to moderate depression; and patients who had previously failed to show an appreciable response to other antidepressant treatment. Analysis of global safety ratings revealed that zimeldine is significantly safer than imipramine, with a lower incidence of adverse symptoms involving the autonomic nervous system, especially anticholinergic reactions. No significant difference was observed between the two groups with respect to abnormal laboratory reports. One zimeldine patient developed symptoms suggesting a hypersensitivity reaction (fever, skin eruption and elevation of plasma levels of transaminases), which led to the patient's withdrawal from drug treatment.

A double-blind study of zimelidine, a serotonin uptake inhibitor, and desipramine, a noradrenaline uptake inhibitor, in endogenous depression. II. Biochemical findings

In a comparative evaluation of zimelidine, a potent serotonin (5-HT) uptake inhibitor, and desipramine, a potent noradrenaline (NA) uptake inhibitor, 65 hospitalized patients with endogenous depression were evaluated for the following biochemical variables: 5-HT uptake in platelets, 5-HT concentration in whole blood, inhibition of the 5-HT and NA accumulation in rat hypothalamic synaptosomes incubated in the patients' plasma, the excretion of 4-hydroxy-3-methoxyphenyl glycol (HMPG) in urine and the pretreatment levels of the amine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and HMPG in cerebrospinal fluid (CSF). results of the biochemical studies confirmed that zimelidine and desipramine have different profiles with respect to monoamine uptake. Thus zimelidine caused more marked inhibition of 5-HT uptake than desipramine, especially in rat brain synaptosomes incubated in the patient's plasma. Desipramine plasma was much more effective than zimelidine plasma in inhibiting NA uptake in the same preparation. The urinary excretion of HMPG decreased significantly during desipramine treatment but remained unchanged during zimelidine treatment. The combined clinical and biochemical results indicated that patients with low pretreatment levels of 5-HIAA and HVA in CSF responded significantly better to zimelidine than patients with high levels of 5-HIAA and HVA. On the other hand, patients with high levels of 5-HIAA and HVA. On the other hand, patients with high levels of HMPG in CSF tended to respond better to desipramine than those with low levels of this NA metabolite.

A double-blind study of zimelidine, a serotonin uptake inhibitor, and desipramine, a noradrenaline uptake inhibitor, in endogenous depression. I. Clinical findings

A comparative evaluation of zimelidine, a potent and selective serotonin (5-HT) uptake inhibitor, and desipramine, a potent noradrenaline (NA) uptake inhibitor, was carried out in a 4-week randomized, double-blind study in 65 hospitalized patients with endogenous depression. For evaluation of the clinical effect, Hamilton Rating Scale for depression (HRS) and a 14-item scale chosen from the Comprehensive Psychopathological Rating Scale (CPRS) were used. The concentration of drug in plasma was determined on the same days as the clinical ratings. There were no significant difference in the overall therapeutic effect between the two drugs. However, zimelidine had significantly better effect on anxiety. Although both agents were well tolerated, the zimelidine-treated patients reported significantly less severe anticholinergic side effects. Body weight did not change significantly in either treatment group. In the total material ther were no significant correlation between plasma concentrations of zimelidine, norzimelidine and desipramine and the amelioration score of either HRS and CPRS.

Effects of zimelidine and desipramine on serotonin and noradrenaline uptake mechanisms in relation to plasma concentrations and to therapeutic effects during treatment of depression

The selective inhibitors of neuronal 5-hydroxytryptamine (5-HT) and noradrenaline (NA) uptake, zimelidine and desipramine, were compared in a double blind crossover study of 40 inpatients with endogenous depression. The clinical effects of these two drugs and some biochemical variables related to the monoamine systems were studied during 4 weeks' treatment. Patients with a low pretreatment level of 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF) (less than 20 ng/ml) responded significantly better to zimelidine treatment than those with a high pretreatment level (greater than 20 ng/ml). In the group treated with desipramine no difference in therapeutic outcome was obtained between patients with low and high pretreatments levels of 5-HIAA in the CSF. Attempts to correlate the steady state plasma concentrations of zimelidine, norzimelidine and desipramine with the therapeutic effect were unsuccessful. The plasma concentration of norzimelidine demonstrated a significant (P less than 0.05) positive correlation with age. The mean value of the uptake of 14C-5-HT in the patient's platelets, when measured before the treatment, was significantly (P less than 0.05) lower than found in a control group. Zimelidine, mainly via its metabolite norzimelidine, caused a pronounced inhibition of uptake of 14C-5-HT in platelets, decrease in whole blood 5-HT and inhibition of accumulation of 14C-5-HT in rat hypothalamic synaptosomes incubated in the patients plasma. Desipramine produced a slight inhibition of accumulation of 14C-5-HT in rat synaptosomes, but a marked inhibition of uptake of 14C-5-HT in the patient's platelets and a decrease in whole blood 5-HT. The accumulation of 3H-NA in rat synaptosomes incubated in the patient's plasma was strongly inhibited by desipramine treatment but only slightly affected by zimelidine.