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Previously, the opioid peptide Tyr-D-Ala-Gly-(NMe)Phe-CH2Cl (DAMCK) has been shown to bind irreversibly to mu opioid receptors in vitro. In the present work, the antinociceptive effect of DAMCK has been evaluated. Rats treated systemically with DAMCK (1-100 pg/kg) displayed a dose-dependent increase in tail-flick analgesia that peaked by 15 min, then stayed(More)
BACKGROUND Online gaming has become increasingly popular. However, this has led to concerns that these games might induce serious problems and/or lead to dependence for a minority of players. AIM The aim of this study was to uncover and operationalize the components of problematic online gaming. METHODS A total of 3415 gamers (90% males; mean age 21(More)
There is an ongoing debate in the literature whether problematic Internet use (PIU) and problematic online gaming (POG) are two distinct conceptual and nosological entities or whether they are the same. The present study contributes to this question by examining the interrelationship and the overlap between PIU and POG in terms of sex, school achievement,(More)
Nociceptin/orphanin FQ (N/OFQ) is the endogenous ligand for the N/OFQ peptide receptor (NOP). Binding studies have relied on [leucyl-(3)H]N/OFQ, but as this is an agonist G-protein coupling will affect affinity. In this paper, we describe a new [(3)H]labeled NOP antagonist, [Nphe(1),4'-(3)H-Phe(4),Arg(14),Lys(15)]N/OFQ-NH(2) ([(3)H]UFP-101). We have(More)
The rise and growing popularity of online games has led to the appearance of excessive gaming that in some cases can lead to physical and psychological problems. Several measures have been developed to explore the nature and the scale of the phenomenon. However, few measures have been validated psychometrically. The aim of the present study was to test the(More)
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The Derogatis symptom checklist (SCL-90-R) and its short version, the Brief Symptom Inventory (BSI), are widely used instruments, despite the fact that their factor structures were not clearly confirmed. The goals of this research were to compare four measurement models of these instruments including one-factor, nine-factor, a second-ordered factor model(More)
The use of substances to enhance human abilities is a constant and cross-cultural feature in the evolution of humanity. Although much has changed over time, the availability on the Internet, often supported by misleading marketing strategies, has made their use even more likely and risky. This paper will explore the case of Mitragyna speciosa Korth.(More)
Receptor binding properties of the naturally occurring opioid heptapeptide MERF were studied in rat brain membrane preparations using tritium-labeled derivative of the peptide with 40 Ci/mmol specific radioactivity. Binding assays were performed in the presence of broad-spectrum peptidase inhibitors at 0 degree C. Under these conditions, the equilibrium(More)
A tritiated heptapeptide, [3H]Tyr-Gly-Gly-Phe-Met-Arg-Phe ([3H]Met-enkephalin-Arg6-Phe7), with high specific radioactivity has been synthesized in order to characterize its opioid binding activity to frog brain membrane fractions. The apparent KD value of the radioligand calculated from homologous displacement experiments was 3.4 nM, and the maximal number(More)