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Introduction Blood platelets can be considered a reliable peripheral model of presynaptic serotonergic neurons, as they are endowed with a 5-HT reuptake transporter similar to that present in the brain cells (Marazziti et al., 2004). The biological basis of the patophysiology of obsessive-compulsive disorder (OCD) is centered on serotonergic system, although evidences of both dopaminergic and adrenergic systems involvement are consistent (Westenberg et al., 2007). A possible role of second messengers, such as cyclic adenosine monophosphate (cAMP) signaling, in the development of OCD has been recently postulated, although evidences are meager and, in some cases, contradictory (McDougle et al., 1999). The aim of the present study was to explore and to compare the adenylate cyclase (AC) activity either in basal conditions, either after the stimulation by isoprenaline (ISO) in platelets of OCD patients and healthy control subjects. Also, AC activity was measured both in the absence and in the presence of α- and β- adrenoreceptor antagonists. Materials and methods Forty patients (20 men and 20 women, aged between 23 and 34 years; mean±SD: 26.5 ± 4.8) were included in the study. All of them met Diagnostic and Statistic Manual of Mental Disorders 5th edition (DSM-5) criteria for OCD, were not currently depressed, nor had any history of mood disorders or any other comorbid conditions. This group was compared to a similar one, composed by 40 healthy volunteers patients (20 men and 20 women, aged between 21 and 32 years; mean±SD: 24.6 ± 6.3), all of them without familiar or personal history of major psychiatric disorders. The severity of OC symptoms was evaluated by means of the Yale Brown Obsessive-Compulsive Scale (Y-BOCS). Thirty (30) ml of blood were collected from fasting subjects between 8.00-10.00 a.m. to avoid circadian rhythm interference. Results The platelet basal AC activity was similar in OCD patients and healthy subjects. The addition of 10 μM ISO enhanced significantly (p Discussion No difference in the basal AC activity in platelet membranes of healthy subjects and OCD patients was found. The addition of 10 µM ISO to platelet membranes provoked a significant stimulation of the enzyme activity of the same magnitude in the two groups. Our findings suggests that, at our experimental conditions, there is an inhibitory component of ISO effect on platelet AC, due to the agonist interaction with α2 receptors, at its higher concentrations (> 1 μM). These data suggest the presence of a condition of supersensitive β-receptors in platelets of OCD patients that, perhaps, could reflect (or provoke) alterations of the intracellular signaling system mediated by the cAMP and of the related kinases. In conclusion, the results of the present study suggest that abnormal second messenger pathways in OCD may be also related to cathecolamine system disturbances, which might open new therapeutic strategies especially in resistant patients who do not respond to serotonergic medications.

Pharmacological studies indicate a functional interaction between the serotonergic and oxytocinergic systems. In particular, some selective serotonin (5-HT) reuptake inhibitors, such as citalopram and fluvoxamine, seem to exert part of their antidepressant effects through oxytocin (OT) release. Further, the administration of fenfluramine, a serotonergic agonist, to healthy subjects increases plasma OT levels. Interestingly, immunocytochemical and double-immunofluorescent techniques revealed a high degree of overlap between 5-HT transporter (SERT)-labeled fibers and OT-containing cells in the paraventricular and supraoptic nuclei of primate hypothalamus. These findings suggest that the influence of 5-HT on OT system might be mediated by SERT. In this study, we explored the possible existence of a link between OT and SERT in human subjects, by means of two peripheral markers, the platelet SERT, as measured by [³H]-paroxetine ([³H]-Par) binding, and plasma OT levels. As far as [³H]-Par binding parameters are concerned, the Bmax (mean ± SD, fmol/mg protein) was 1155 + 130 and the Kd (mean ± SD, nM) was 1.31 ± 0.61. The OT plasma levels (mean ± SD, pg/ml) were 1.14 ± 1.07. A significant and positive correlation was found between plasma OT levels and Kd values (correlation coefficient: r: 0.466, p = .038). This result represents the first evidence of an interaction between OT and SERT, as measured by [³H]-Par binding, at peripheral levels in humans. Given the several activities mediated by both OT and 5-HT, such a relationship might provide new perspectives and insights into psychiatric disorders and/or social relationship disturbances, as well as novel treatment strategies overcoming and/or integrating the serotonergic paradigm.

Introduction Different findings suggest that the serotonin (5-HT) sys-tem may be involved in both the regulation of aggres-sion and the pathophysiology of obsessive-compulsive disorder (OCD). Our study aimed to evaluate the aggres-sive features of a group of OCD patients and to explore possible correlations with a serotonergic marker, namely platelet 5-HT transporter. Methods Psychopathological and bio-logical patterns were compared with those of a group of healthy controls and those of patients with major depres-sion. Twenty-one patients affected by OCD, 21 by de-pression and 21 healthy controls were included in the study. Aggressive features were measured by means of the Buss and Durkee Hostility Inventory (BDHI). The platelet 5-HT transporter was evaluated by means of the 3H-paroxetine binding parameters (maximum binding capacity, Bmax and dissociation constant, Kd). Results OCD patients showed a total score on the BDHI not significant-ly different from that of healthy controls and lower than that of depressed patients. The factor profile was similar in the 3 groups, but higher in the depressed patients. The irritability, resentment, guilt, negativism and suspicious-ness factors were significantly more pronounced in de-pressed patients. Some sex-related difference in single factors were also observed. The Bmax of 3H-paroxetine binding was lower in OCD patients than in depressives or healthy controls. Discussion OCD patients were more similar to healthy controls than to depressed patients with regard to aggressive features measured by means of the BDHI. Conclusions These results suggest that aggression in OCD is a complex phenomenon that probably requires specific instruments of evaluation.

IntroductionInternet addiction (IA) is considered part of the so-called “new technologies addictions” group, that in turn belongs to a wider, novel group of abnormal behaviors defined “no-drug addictions” or “behavioral addictions”. Similarly to substance abuse, there is the risk either to arouse symptoms like craving, tolerance and habituation either to develop a full-fledged addiction to the Internet.AimThe aim of this study is to examine the current pattern of Internet use and eventually of IA, as well as their main characteristics, in a group of high-school students from Calabria, a Southern Italian region.MethodsFive hundred high-school students (42% boys, 58% girls, mean age SD ± 16.23 years) volunteered for this study. A specific questionnaire of 45 items with 5 possible answers ranging between “never” and “very often” on a Likert scale was developed.ResultsMost of the young subjects interviewed owned a smartphone with Internet, and claimed to spend more time online than at the beginning. Nearly everybody had an active account in a least one social network. A small withdrawal from social relationships and from sport activities emerged in this group.ConclusionsAlthough about 10% of examined students presented IA symptoms, our findings cannot be considered representative of the total high-school population, these results underline the need of further investigation and awareness. In fact, many underestimated, vague, and other unspecific neuropsychiatric symptoms, such as alterations of sleep-wake pattern, chronic fatigue, headache, visual problems, carpal tunnel syndrome and eventually anxiety or depression may be underlying to an unrecognized condition of IA.Disclosure of interestThe authors have not supplied their declaration of competing interest.