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Background: Tobacco smoking is associated with reduced monoamine oxidase A (MAOA) activity. Smoking-associated low MAOA activities in pregnancy and in newborns may have negative perinatal and postnatal consequences. We aimed to compare, in everyday clinical conditions, biomarkers of MAOA activity in smoking (SPW) and lifetime nonsmoking pregnant women (NSPW) and in cord blood and to assess the newborns' behavior during the first 48 hours of life., Methods: Thirty SPW and 29 NSPW in their second trimester of pregnancy were included. Plasma MAOA dependent metabolites of norepinephrine: dihydroxyphenylglycol; dopamine: homovanillic and dihydroxyphenylacetic acid; and serotonin: 5-hydroxy-indol acetic acid were measured at the end of the second trimester, at delivery, and in arterial cord blood along with plasma cotinine. The newborns' discomfort was evaluated every 8 hours by a standardized questionnaire., Results: The SPW smoked, on average, 73 cigarettes per week at the end of second trimester and 80 cigarettes per week at delivery. Mean plasma cotinine was 84 ng/mL, 105 ng/mL, and 95 ng/mL at the end of second trimester, at delivery, and in cord blood, respectively (NSPW < 10 ng/mL). Plasma markers of MAOA activity, in particular those reflecting dopamine's catabolism, were significantly lower in SPW and in the arterial cord blood of their newborns than in NSPW and their newborns. Newborns of SPW showed significantly more facial discomfort than those of NSPW., Conclusions: Smoking is associated with MAOA inhibition in pregnant women and in their newborns at birth. Further studies are needed to estimate the behavioral significance of these findings.

Background: There are numerous reports of decreased binding to platelet serotonin transporter (5-HTT) in depression, suggesting that it might be considered a trait marker of depression. To further investigate whether reduced 5-HTT function could be an endophenotype in manic depressive illness, we looked for abnormalities of platelet 5-HTT among subjects who are potential carriers of genetic vulnerability to manic depressive illness (MDI)., Methods: Blood samples were obtained from 20 unaffected relatives from families with at least two individuals with bipolar disorder and from 19 control participants. Plasma 5-HIAA, platelet 5-HT, and [3H] imipramine binding were measured., Results: Unaffected relatives manifested lower platelet 5-HTT function than control participants as revealed both by reduced number and diminished affinity of imipramine binding sites and diminished platelet 5-HT content., Conclusions: These preliminary results suggest that reduced 5-HTT function could be considered a trait marker or an endophenotype in MDI.

The main metabolites of dopamine, noradrenaline, and serotonin, homovanillic acid, methoxyhydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA), were estimated in plasma of 20 drug-naive young male schizophrenic patients and 21 healthy controls. Although there were no significant differences between the two groups, multiple regression analysis revealed strong associations of the patients' 5-HIAA and MHPG plasma levels to their scores in the Brief Psychiatric Rating Scale items. 5-HIAA levels were mainly related positively to hostility and negatively to somatic concern, and MHPG positively to disorientation and negatively to emotional withdrawal and uncooperativeness. The results suggest that levels of the neurotransmitter metabolites may be related to certain psychological dysfunctions of the patients rather than to disease entities.

Studies of neurotransmitter kinetics based on intraventricular injections of radio-labeled metabolites have been limited by several problems, including the inability of most investigators to recover more than 45% of the infected isotope from brain homogenates within several minutes after the injection...

Seasonal changes of several serotonin-related measures in plasma and whole blood of healthy individuals were determined every 4 weeks. Plasma serotonin (5-HT) shows very marked changes throughout the year, with maximum values during the summer and lowest values in the fall, whereas its metabolite 5-hydroxyindoleacetic acid (5-HIAA) follows a somewhat contrary pattern. The sum of 5-HT plus 5-HIAA in plasma thus does not change significantly during the year and follows the evolution of total plasma tryptophan (TP). The difference of 5-HIAA minus 5-HT in plasma, which is indicative of the efficacy of degradative processes of 5-HT in the periphery, is strongly dependent on the season and suggests a higher degradation of 5-HT during fall-winter. Unlike plasma TP and whole blood 5-HT, significant correlations among plasma 5-HT, 5-HIAA, and the ambient temperature were found. The possible significance and relationship of these findings to the seasonality of major depression is discussed.