Giuseppe Santagostino

A sensitive fluorimetric method for determination of platelet-bound and plasma free serotonin

A sensitive and specific fluorimetric assay for blood platelet-bound and plasma free serotonin is described. Serotonin is concentrated and purified on Amberlite CG-50 resin, eluted by 0.15 mol/l HCl and its native fluorescence is read at 295/350 nm. The good recovery (90% about), reproducibility and sensitivity (the smallest amount detectable is 5 ng) make the assay particularly useful for the detection of free serotonin in plasma. The whole procedure is rapid enough to permit the analysis of 15--20 samples within one working day and thus the method is suitable for routine determination of serotonin in biological specimens.

Blood noradrenaline and 5-HT levels in depressed women during amitriptyline or lithium treatment.

Noradrenaline levels and platelet and free serotonin concentrations were studied in depressed women in-patients (n=78) before and during amitriptyline (n=41) or lithium treatment (n=37). Pronounced monthly differences in platelet serotonin level have been shown in these subjects before treatment. In all clinical subgroups (neurotic, involutional, manic-depressive patients) a significant fall in platelet serotonin level was observed with amitriptyline medication while an increase was noted with lithium. No significant correlations between serotonin concentrations and clinical outcome were found. Amitriptyline treatment also produced a decrease in peripheral noradrenaline concentration in all subgroups, while an increase was observed with lithium. Some correlations between noradrenaline level and degree of depression were noted in patients treated with amitriptyline or lithium. A more extended analysis of blood amine levels could supply meaningful information on the peripheral action of antidepressive drugs on noradrenaline and serotonin concentrations in depression.

Catecholaminergic, Neuroendocrine and Anxiety Responses to Acute Psychological Stress in Healthy Subjects: Influence of Alprazolam Administration

We studied the effect of alprazolam (APZ) in 12 healthy volunteers on the psychological stress-induced activation of emotion and on the pituitary-adrenal, adrenomedullary and sympathoneuronal systems. After 3 days of placebo or APZ (1 mg/day orally) administration, we examined plasma levels of adrenocorticotropic hormone, cortisol, L-3,4 dihydroxyphenylalanine, dopamine, norepinephrine (NE), epinephrine, metanephrine, normetanephrine, homovanillic acid, vanillylmandelic acid, 3-methoxy-4-hydroxy phenyglycol, urinary levels of cortisol and catecholamines, circulatory responses and state anxiety levels in subjects undergoing psychological stress based on viewing horror, violence, danger and war film clips. Film viewing produced modest rises of state anxiety levels, of plasma NE concentration and of diastolic blood pressure in both the placebo and drug groups. APZ significantly reduced anxiety levels at the beginning of the experimental session and caused a decrease of noradrenergic and dopaminergic neurotransmitter and cortisol concentrations. Our data suggest that APZ reduced anxiety related to the expectation of the event, while the circuitry between structures responsible for anxiety and peripheral sympathoneural function was still found to be partly sensitive to film viewing.

Aspects of amitriptyline and nortriptyline plasma levels monitoring in depression

Fifty-nine depressed female inpatients were treated with 100 mg amitriptiline (AMT) IM for 4 weeks. Depression ratings and determinations of the parent drug and nortriptyline (NT) were performed weekly. No direct relationship between plasma AMT + NT concentrations and therapeutic response was apparent, but beneficial therapeutic responses and significantly lower side-effect scores were more frequently noted in subjects with concentrations in the 100–200 ng/ml range. AMT + NT concentrations were significantly correlated with age. No significant difference was found in the number of responders between younger and older subjects with two clinical improvement criteria; however, a significant difference emerged when a third more restrictive clinical outcome criterion was adopted. The implications of the present findings for patient treatment and for the interpretation of previous studies are discussed. The data collected point to a possible usefulness of monitoring AMT and NT plasma levels, even if further investigations are needed.

Urinary 3-methoxy-4-hydroxyphenylglycol determination using reversed-phase chromatography with amperometric detection

A reversed-phase liquid chromatographic method with amperometric detection has been developed for the determination of urinary 3-methoxy-4-hydroxyphenylglycol. Before and after enzymatic deconjugation, it was purified by an extraction procedure and rapidly quantified under isocratic conditions. The 24-h excretion profile in normal human subjects (eight males and seven females) was determined; our results are consistent with those arrived at in a number of other studies. The present method is highly sensitive and selective; in addition, a good degree of precision is assured by use of 4-methoxy-3-hydroxyphenylglycol as internal standard.

Cell membrane modifications in rabbit isolated hepatocytes following a chronic amitryptiline treatment

Abstract The influence of a chronic amitryptiline pretreatment on the transport of the same drug through the cell membrane has been studied in rabbit isolated hepatocytes, comparing the amount of amitryptiline metabolized by intact hepatocytes with that by disrupted ones. The results show that the amitryptiline metabolism in intact hepatocytes from chronically pretreated rabbits is significantly lower than that in the disrupted ones at all incubation times. By contrast this difference is not present between intact and disrupted hepatocytes from untreated rabbits. These findings support evidence for the hypothesis that the amitryptiline pretreatment affects the permeability of the hepatocyte membrane, thus preventing the penetration of the drug itself into the cells and consequently decreasing its metabolism.

Normal-Range Plasma Catecholamines in Patients with Generalized and Acrofacial Vitiligo: Preliminary Report

BACKGROUND There is a body of evidence that neutral factors may play a role in the pathogenesis of vitiligo. OBJECTIVE We look for the existence of a relationship between vitiligo and monoaminergic systems. METHODS We use high-pressure liquid chromatography to measure the plasma level of catecholamines, their precursor 3,4-dihydroxyphenylalanine and their metabolites 3-methoxy-4-hydroxy phenylglycol (MHPG), normetanephrine (NMN), metanephrine and homovanillic acid (HVA). Forty patients with the generalized (n = 31) and acrofacial (n = 9) types of vitiligo are studied. RESULTS Significant differences are not found either between males and females or between the entire group of patients and the controls. HVA and NMN levels significantly correlate with age (r = 0.332, p < 0.05, and r = 0.331, p < 0.05, respectively). Significant correlations are also seen either between noradrenergic or between dopaminergic parameters (norepinephrine vs. MHPG, r = 0.326, p < 0.05; dopamine vs. HVA, r = 0.540, p < 0.01). When the patients are grouped on the basis of vitiligo type or age of disease onset, the plasma mean levels of the neural compounds are always nonsignificantly different from those of the controls. However, both catecholamines and metabolites show higher, although not significant, concentrations in patients with a shorter duration of disease. CONCLUSION Monoaminergic systems seem unlikely to be related to vitiligo, at least to the generalized and acrofacial types. However, variations cannot be excluded in genetically predisposed individuals during the onset or the active phases of disease.

Clinical and biochemical responses to therapy in Alzheimer's disease and multi-infarct dementia

SummaryMemory performance, central monoaminergic function and sympathetic nerve activity were studied in patients with dementia of the Alzheimer type (DAT) or with multi-infarct dementia before and after 4 weeks with single or combined drug therapy (choline-piracetam). Analysis of the levels of 3-methoxy-4-hydroxyphenylglycol (MHPG), 3-methoxy-4-hydroxyphenylacetic acid (HVA) and 5-hydroxyindolacetic acid in the cerebrospinal fluid (CSF) and also in urine (plus 3-methoxy-4-hydroxy mandelic acid) showed that the basal values of HVA in the CSF and urine were lower in the more severely demented compared with the mildly demented subjects in both groups. The combined drug treatment resulted in a statistically significant increase in the MHPG level in the CSF of mildly demented subjects of the DAT group, while it seemed not to influence the other monoamine metabolites. The sympathetic nerve activity was similar in both patient groups and was unchanged after therapy. These findings suggest a dopaminergic deficit in advanced stages of the disease and a possible enhancement of the central noradrenergic output with therapy. No effects of therapy on memory performance or correlations between monoamine levels and memory test scores were noted.

Presence of an acid metabolite of amitryptiline in rabbit urine.

Abstract The Identification and quantitative evaluation of hydroxylated and demethylated basic metabolites of amitryptiline in rabbit, have been previously reported by us.1–3 This paper describes further investigations on amitryptiline metabolism which have led us to discover a carboxylic metabolite formed through the oxidative deamination of the drug.

Amitriptyline action on sympathetic neuronal function in depressed women.

1. Noradrenaline plasma levels and cardiovascular function modifications with orthostatic challenge during therapy were studied in 59 female depressed inpatients treated with 100 mg amitriptyline daily by intramuscular route for 4 weeks.