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Biomedical subjects

C Benkelfat

Publications and source records attributed to C Benkelfat.

At least 19 recordsLinked to original sources

Plasma catecholamines and their metabolites in obsessive-compulsive disorder.

Plasma catecholamines and their metabolites were sampled in 13 medication-free patients with obsessive-compulsive disorder (OCD) and 29 normal controls. In addition to severe OCD symptoms, the patients had significantly higher anxiety, tension, and resting pulse rates than the controls. Nonetheless, mean plasma concentrations of norepinephrine (NE) and epinephrine (E), the catecholamine metabolites 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA), and the stress-related hormone cortisol did not differ between OCD patients and normal controls. When the patients and control populations were combined and average plasma NE and E levels calculated over 35 min, subjects with a higher mean NE output (greater than 1.1 pm/ml) had higher Profile of Mood States depression scores than subjects with a low NE output (less than 1.1 pm/ml). Altogether, these results indicate that elevated plasma catecholamine measures are not likely to be associated with the pathophysiology of OCD.

Adult

Local cerebral glucose metabolic rates in obsessive-compulsive disorder. Patients treated with clomipramine.

In a recent study, we reported abnormal local cerebral glucose metabolic rates in the orbital frontal cortex of patients with obsessive-compulsive disorder. Eight patients with obsessive-compulsive disorder scanned previously were scanned again during treatment with the tricyclic antidepressant clomipramine hydrochloride. Comparisons of local cerebral glucose metabolic rates for both groups showed a relative decrease in regions of the orbital frontal cortex and the left caudate, and an increase in other areas of the basal ganglia, including the right anterior putamen. When comparing patients who responded well to clomipramine with those who were either poor or partial responders, we found significant decreases only in the left caudate of patients who responded well to the drug. The present study suggests that clomipramine-induced improvement in obsessive-compulsive symptoms is associated with a return of regional brain metabolism to a more normal level in regions of the orbital frontal cortex and the caudate nucleus.

Adult

Diagnostic and therapeutic value of testing stimulation of thyroid-stimulating hormone by thyrotropin-releasing hormone in 100 depressed patients.

The thyrotropin-releasing hormone (TRH) test was performed in 100 depressed patients, including 73 patients with a major depressive episode (MDE) according to DSM-III. Thirty-one patients subsequently received an antidepressant with a predominant serotoninergic action (indalpine or citalopram), and 27 patients received a noradrenergic antidepressant (maprotiline). The diagnostic value of the TRH test was not conclusive for any of the subgroups of depressed patients: MDE, MDE with melancholia or MDE in bipolar patients. Similarly, the value of the TRH test in the choice of antidepressant treatment according to the monoaminergic action was not convincing. These results are discussed in the light of the data of the international literature.

Adult

Clomipramine in obsessive-compulsive disorder. Further evidence for a serotonergic mechanism of action.

Data from several previous studies link clomipramine's potent serotonergic effects to its clinical efficacy in reducing the symptoms of obsessive-compulsive disorder (OCD). To investigate this relationship further, we administered the serotonin (5-HT) receptor antagonist, metergoline, and placebo to ten patients with OCD in a crossover study carried out under double-blind, random-assignment conditions. In a previous study of untreated patients with OCD, we found no differences in the behavioral response to single-dose administration of metergoline or placebo. In the present study, patients with OCD receiving clomipramine hydrochloride on a long-term basis (with an average 40% lessening in OC symptoms) responded to a four-day period of administration of metergoline with significantly greater self- and observer-rated anxiety compared with the four-day placebo period. Obsessive-compulsive symptoms also tended to be greater during the metergoline phase, with significant drug-time interactions for both OC symptoms and anxiety peaking on day 4 of the metergoline phase. As anticipated, metergoline lowered plasma prolactin concentrations (providing evidence of physiologically significant 5-HT antagonism) but did not alter plasma clomipramine concentrations. These data further support the hypothesis that clomipramine's therapeutic behavioral effects in OCD are mediated via serotonergic mechanisms.

Adult

Cerebral glucose metabolic rates in obsessive compulsive disorder.

Brain metabolism was measured with positron emission tomography and [18F] 2-fluoro-2-deoxyglucose in normal subjects and in patients with obsessive compulsive disorder (OCD) while they performed a continuous auditory discrimination task designed to evaluate the functional localization of sustained attention. Data on 8 nondepressed patients with OCD were compared with 30 normal volunteers. We observed significantly higher normalized regional metabolism both in the right orbital frontal cortex (p = 0.002, two-tailed t test) and in the left anterior orbital frontal cortex (p = 0.017, one-tailed t test) and in patients with OCD as compared to normal controls. We observed no normalized glucose metabolic differences in basal ganglia structures in patients with OCD as compared to our normal controls. There were no statistical differences in global glucose metabolic values between the OCD and the control group. Our findings are consistent with the findings of Baxter et al. (Arch Gen Psychiatry 44:211-218, 1987). Regions in the parietal cortex also appear to show differences in this preliminary study.

Adult

Apparent down-regulation of rat brain mu- and kappa-opioid binding sites labelled with [3H]cycloFOXY following chronic administration of the potent 5-hydroxytryptamine reuptake blocker, clomipramine.

This study examined the effect of chronic clomipramine administration on opioid mu- and kappa-binding sites. Clomipramine (5 mg kg-1 day-1) or saline was administered to rats via osmotic minipumps for 3 days or 28 days. Lysed-P2 brain membranes were prepared and preincubated for 60 min without (control membranes) or with 1 microM of the mu-selective acylating agent, 2-(4-ethoxybenzyl)-1-diethylaminoethyl-5-isothiocyanatobenzimid azole-HC1 (BIT), to deplete membranes of mu-binding sites. [3H]6-Desoxy-6 beta-fluoronaltrexone ( [3H]cyclo FOXY) was used to label mu and kappa-binding sites. Weighted nonlinear least squares analysis of cycloFOXY binding surfaces permitted determination of the Kd and Bmax values of mu- and kappa-binding sites in control and treated rats. Subacute (3 days) administration of rats with clomipramine had no significant effect on [3H]cycloFOXY binding. Chronic (28 days) administration of clomipramine produced a small (approximately 10%) but statistically significant decrease in the Bmax. These findings are discussed in reference to other studies that have examined the effect of chronic antidepressant administration on opioid receptors, and speculate that the endogenous opioid systems may play a role in obsessive-compulsive disorder.

Animals

Obsessive-compulsive disorder as a 5-HT subsystem-related behavioural disorder.

Involvement of the brain serotonin (5-HT) neurotransmitter system in obsessive-compulsive disorder (OCD) was originally suggested on the basis of therapeutic effects found with the semiselective serotonin uptake inhibitor, clomipramine. More recent studies directly comparing clomipramine with non-selective or norepinephrine-selective uptake inhibitors, such as desipramine or nortriptyline, as well as studies with new, more selective serotonin uptake inhibitors, including fluvoxamine and fluoxetine, have supported that hypothesis. Clomipramine's antiobsessional effect has been augmented with the serotonin precursor, L-tryptophan, or with lithium, which has prominent serotonergic effects. Patients whose OCD symptoms improved on clomipramine worsened when the drug was discontinued (regardless of duration of therapy) and improved when clomipramine was reinstituted. OCD symptoms also worsened when metergoline, a 5-HT antagonist, was given to patients who had improved with clomipramine. Metergoline given alone had no effect. Administration of m-chlorophenylpiperazine (m-CPP), a 5-HT receptor agonist, to untreated OCD patients increased their anxiety, depression, and dysphoria, and exacerbated their OC symptoms. After 4 months of clomipramine therapy, m-CPP failed to produce the same behavioural effects, suggesting an alteration of a 5-HT subsystem (possibly downregulation of some 5-HT receptors). The data reviewed suggest an important role for an abnormal brain 5-HT subsystem in patients with OCD.

Brain

Effects of trazodone on the sleep of depressed subjects--a polygraphic study.

The effects of 400-600 mg trazodone on the sleep patterns of ten depressed in-patients treated for 5 weeks were studied during the initial (days 1-3) and terminal (days 26-28) treatment periods. The sleep parameters were compared to those obtained from three sleep recordings performed just prior to the initiation of the treatment and after 2 adaptation nights at the end of a 2-week drug-free period. At the same time, the clinical evolution of patients was evaluated weekly using MADRS and Hamilton-Anxiety scales for anxiety-depression symptomatology and Spiegel and Norris sleep scales. Weekly blood samples were collected to measure plasma levels of trazodone and, at the end of the study, the elimination half-life at steady state was calculated by repeated measurements of plasma levels. Clinical improvement, as assessed by a reduction of more than 60% in MADRS scale scores, was accompanied by evidence of the definitely beneficial effects of trazodone on the disturbed sleep of these depressed patients. From the beginning of treatment, there was a hypnotic-like effect (increase in total duration of sleep and stage II, decrease in sleep latency and intrasleep awakenings). In addition, records at the end of the study showed an increase in delta sleep and an increase in REM latency, an effect classically associated with an antidepressant action. These particularly valuable effects of trazodone on sleep would suggest that this drug should especially be given in cases of depression with major insomnia.

Adult

Lack of correlation between DST results and urinary MHPG in depressed inpatients.

Abnormalities of noradrenaline metabolism and of the activity of hypothalamic-pituitary adrenal axis (HPA) have been reported in depression. To study the possible relationship between these 2 parameters, urinary excretion of 3-methoxy-4-hydroxy-phenylethyleneglycol (MHPG) and Dexamethasone Suppression Test (DST) were analyzed in 58 depressed patients. A positive correlation was found between the age of depressed patients and 24-h urinary excretion of MHPG. Twenty-two patients (38%) were DST non suppressors. Pre-DST plasma cortisol levels were significantly higher in non suppressors than suppressors. No difference was found however between urinary MHPG levels in suppressors and non suppressors. There was no correlation between pre-DST plasma cortisol and levels of urinary excretion of MHPG. These results do not support the hypothesis of a relationship between these 2 parameters. However, when depressed patients were separated into two groups according to urinary excretion of MHPG ("high MHPG" and "low MHPG"), the "high MHPG" group included significantly more non suppressors then the "low MHPG" one. This result is not sufficient to demonstrate of link between HPA system activity and central noradrenaline metabolism.

Adult

Changes in [3H]5-HT uptake and [3H]imipramine binding in platelets after chlorimipramine in healthy volunteers. Comparison with maprotiline and amineptine.

In the platelets of normal healthy volunteers (n = 8) taking chlorimipramine (50 mg/day) for 1 week, the saturable uptake of [3H]5-hydroxytryptamine (5-HT) was fully inhibited at the end of the week, but returned to control values after 2 weeks washout. The Bmax of [3H]imipramine binding was decreased by 63% at the end of the treatment and remained significantly decreased below control values after 1 week washout, whereas the Kd values were increased at the end of the treatment, but had returned to baseline values after 1 week washout. The time course of recovery following the administration of chlorimipramine showed some variation between subjects, but it was necessary to wait up to 4 weeks of washout before the Bmax of [3H]imipramine returned to baseline levels. In contrast, neither 1-week treatment with maprotiline (50 mg/day) nor with amineptine (100 mg/day) changed the parameters of [3H]5-HT uptake or [3H]imipramine binding in platelets from healthy volunteers. These results support the following conclusions. (1) [3H]Imipramine binding in platelets can be down-regulated by relatively low, subtherapeutic doses of chlorimipramine. (2) It is possible to dissociate [3H]imipramine binding parameters from [3H]5-HT uptake because the time course of recovery was clearly different, indicating that [3H]imipramine labels a site linked with, but different from, the 5-HT recognition site in the transporter complex. (3) A washout of antidepressants of 4 weeks may be needed when studying the parameters of [3H]imipramine binding in platelets from depressed patients if the previous medication involved chlorimipramine. For antidepressants like maprotiline or amineptine, that act through mechanisms other than inhibition of 5-HT uptake, the time of washout appears to be less critical, although it is not possible to rule out the existence of some secondary modifications influencing the 5-HT transporter complex.

Adult

Platelet MAO activity in clinical subtypes of depression and DST suppression.

Platelet MAO activity was measured in 75 hospitalized depressed patients and in 31 healthy subjects. Plasmas post dexamethasone cortisol levels were examined in 73 patients. Results indicate that higher platelet MAO activity does not occur in all, but only in male major depressed patients. No relationship between changes of MAO activity and specific clinical subtypes was found. Platelet MAO activity is not different between DST suppressors and DST non suppressors. The authors suggest that platelet MAO activity may be related to non specific factors such as sex, age, but not to diagnosis of depression.

Adjustment Disorders

Dexamethasone suppression test and the response to antidepressant depending on their central monoaminergic action in major depression.

After 1 mg DST, 25 major depressive patients (DSM-III) received at random either a specific inhibitor of noradrenaline reuptake (Maprotiline) or an inhibitor of serotonin reuptake (Indalpine or Citalopram). After at least 3 weeks of treatment, no difference was found in treatment response between suppressors and non suppressors. This study is unable to confirm the usefulness of the DST in selection of treatment according to its central activity on serotonin or noradrenaline-reuptake.

Adult

Lack of circadian rhythm in plasma levels of 3,4-dihydroxyphenylethyleneglycol in healthy human subjects.

In order to investigate the possible existence of a circadian rhythm in plasma free and sulfate-conjugated 3,4-dihydroxyphenylethyleneglycol (DOPEG), the plasma levels of this metabolite (and for comparison, of melatonin and cortisol) were measured in seven healthy volunteers at 4-h intervals over a period of 24 h. Plasma concentrations of melatonin and cortisol showed distinct diurnal variations with acrophases at 2.5 h and 8.5 h, respectively. In contrast, plasma free DOPEG levels were relatively stable over the 24-h period studied. Sulfate-conjugated and free + sulfate-conjugated DOPEG levels showed a slight, non-significant increase in the early afternoon. These results indicate that in contrast to plasma 3-methoxy 4-hydroxyphenylethyleneglycol, plasma free and conjugated DOPEG levels do not exhibit a circadian rhythm.

Adult

Platelet 3H-imipramine binding and steroid hormones serum concentrations during the menstrual cycle.

The presence of high affinity binding sites for 3H-imipramine (3H-IMI) in human platelets is by now well established. This recognition site is associated with the transporter for 5HT, and may be a biological marker in depression. Fluctuations of other putative biological markers of depression (i.e. platelet MAO activity) have been demonstrated and shown to be correlated with variations in steroid hormones. Therefore, the KD and Bmax of 3H-IMI binding was determined in platelets of young women during the menstrual cycle. Our results indicate that within the limits of intraindividual variations, neither the KD or the Bmax of 3H-IMI binding in platelets is significantly modified during the menstrual cycle.

Adult

Decrease in plasma levels of 3,4-dihydroxyphenylethyleneglycol in major depression.

Plasma levels of free and sulfoconjugated 3,4-dihydroxyphenylethyleneglycol (DOPEG), the main deaminated metabolite of norepinephrine, were measured in a group of 45 hospitalized patients presenting a major depression and a group of 45 healthy subjects, matched for sex and age. Compared to healthy subjects, depressed patients had significantly lower plasma levels of free and sulfoconjugated DOPEG. The ratio of free over conjugated DOPEG was not statistically different in the two groups. The reduction of plasma DOPEG levels in the depressed patients did not appear to be related to the duration of drug-free period and was similar in males and females. There was no statistically significant correlation between plasma DOPEG levels and total score on the Hamilton Rating Scale for Depression. Finally, plasma DOPEG levels did not differ in unior bipolar patients. The present data provides further evidence for a reduced CNS noradrenergic transmission in major depression.

Adolescent

Urinary 3-methoxy, 4-hydroxyphenylethylene glycol and therapeutic response to maprotiline and indalpine in major depression.

The potential value of pretreatment urinary 3-methoxy, 4-hydroxyphenylethyleneglycol (MHPG) levels to predict the therapeutic response to antidepressants was studied by measuring urinary MHPG output in 42 depressed inpatients treated with a selective inhibitor of serotonin (Indalpine) or noradrenaline (Maprotiline) reuptake. Among the 42 depressed inpatients there were 33 cases of major depressive episode. Patients were treated for at least 3 weeks, firstly with intravenous infusions of maprotiline or indalpine which have been administered at random. No difference in pretreatment urinary MHPG levels was found between the responders to indalpine (1.08 +/- 0.48 micrograms/24 h/mg of creatinine) and the responders to maprotiline (1.15 +/- 0.62 micrograms/24 h/mg of creatinine). However, there was a difference in the pretreatment levels of urinary MHPG between the non-responders to indalpine (0.56 +/- 0.28 microgram/24 h/mg of creatinine) and the non-responders to maprotiline (1.37 +/- 0.68 micrograms/24 h/mg of creatinine). No correlation between this biochemical parameter and HDRS score was found. These results indicate that, in this study, there is no obvious relationship between the pretreatment urinary MHPG levels in depressed patients and their therapeutic response to specific inhibitors of noradrenaline or serotonin reuptake. However, there was a positive trend towards a lower pretreatment MHPG level to be associated with lack of response to indalpine.

Adult