Exploratory study to evaluate plasma vasopressin and apelin‐13 levels in children with attention‐deficit hyperactivity disorder

Abstract

Aim: Vasopressin exerts robust influences on social communication and behavior in humans. Apelin is a relatively novel neuropeptide that could counteract vasopressin's actions and has been shown to be closely related with a broad range of physiological functions. Abnormalities in vasopressin and apelin have been detected in a variety of psychiatric disorders, but their relation to attention-deficit hyperactivity disorder (ADHD) is unknown. In the present study, we explored the plasma levels of vasopressin and apelin-13 in children with ADHD.Methods: Thirty-four children with ADHD and 36 healthy controls were enrolled in this study. The severity of ADHD symptoms was assessed via Conners' Parent Rating Scale and Conners' Teacher Rating Scale. Plasma levels of vasopressin and apelin-13 were measured using commercial enzymelinked immunosorbent assay kits. Results:The mean plasma apelin-13 levels were significantly higher in male children with ADHD than in male control subjects; no significant difference was found between the groups for plasma apelin-13 levels in girls or in the entire subject cohort. Plasma vasopressin levels did not show any significant differences between groups. There were no significant correlations between plasma levels of these neuropeptides and scores for Conners' Parent Rating Scale and Conners' Teacher Rating Scale. Conclusion:Our results suggest a sex-specific association between plasma apelin-13 levels and ADHD. Apelin-13 may play a role in the etiopathogenesis of ADHD either with a direct impact on the apelin receptor or via its opposing effect on the vasopressinergic system. Key words: apelin-13, attention-deficit hyperactivity disorder, children, plasma, vasopressin.A TTENTION-DEFICIT HYPERACTIVITY DISOR-DER (ADHD) is a childhood-onset neurodevelopmental condition characterized by inattention, hyperactivity, and/or impulsivity that can persist into adulthood with deleterious effects on social, academic, and behavioral outcomes.1 The etiology of ADHD involves complex interactions of neuroanatomical and neurochemical systems, but the precise neurobiological mechanisms underlying the disorder are currently unclear. Understanding the etiopathogenesis of ADHD would aid in both its diagnosis and in the development of new treatments for this complex disorder.The vasopressinergic system in the brain participates in the modulation of social behaviors, including social communication, parental care, parent-offspring bonding, pair-bonding, and sexual behavior.2 Because social deficiencies are core symptoms of autism spectrum disorders (ASD), in recent years, a growing number of studies have investigated the potential relation between the vasopressinergic system and ASD. [3][4][5] These studies have yielded conflicting results regarding the alteration of blood vasopressin concentrations

New techniques, applications and perspectives in neuropeptide research

“…Furthermore, even slightly different neuropeptide isoforms from the same family can have drastically different effects. Interestingly, even with the development of new, technologically advanced alternatives, older, well-vetted methods are still present in the literature either as a method of analysis or to confirm the observed results (Bilgic et al, 2016;Liu et al, 2016a). Function can be explored at many levels, ranging from the macro (e.g.…”

“…Owing to the typically small size of neuropeptides, western blotting is normally used to assess other, related protein changes or expression of neuropeptide receptors (Bayerl et al, 2016;Liu et al, 2016b). Other complementary examples of a targeted technique are enzyme-linked immunosorbent assay (ELISA) (Bilgic et al, 2016;Javadian et al, 2016) and use of radioactively labeled ligand and a γ-counter (Dhuria et al, 2016). While these methods are excellent if one has a target of interest, a non-biased global view of the dynamic changes of all the neuropeptides is often needed to understand fully the role of neuropeptides and their possible function at the system level.…”

Plasma apelin‐13, attention‐deficit hyperactivity disorder, and environmental exposure to nitrous oxide

“…8 Although these data are indicative of a close relation between APJ and KOR, the functional significance of this receptor heterodimerization (i.e., receptor expression, pattern of desensitization, signal transduction) is unclear and requires further investigation. 9 Additionally, the sex differences noted by Bilgiç et al 1 in AP-13 levels may be related to the role of KOR in regulating vasopressin and oxytocin release 10 and in the sex differences in the pro-depressant effects of KOR activation. 11 The N 2 O-mediated ADHD impairment hypothesis is consistent with not only evidence indicating an adverse effect of air pollution in neuropsychological development but also the significantly higher plasma levels of AP-13.…”

“…B ILGIÇ ET AL. 1 conducted an exploratory study to assess the role of apelin-13 in children with attention-deficit hyperactivity disorder (ADHD). The authors report that mean plasma apelin-13 levels were significantly higher in male ADHD children compared to control children; however, no differences were noted between the groups among the entire subject cohort or in females.…”

Interaction of apelin, elabela and nitric oxide in schizophrenia patients

“…Intra-cerebrovascular injection of APLN was also reported to induce an antidepressantlike effect by activating phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinases 1 and 2 (ERK1/2) signalling pathways in stressed rats, and aid recognition memory (13). In children with attention deficit and hyperactivity disorder, plasma APLN levels were significantly higher in boys than in the control group (14). Furthermore, APLN levels in patients with autistic spectrum disorder were reduced considerably (15).…”