Effects of aromatic ring-substituted phenethylamines on the release of dopamine and serotonin

Fluorescence detection of phenylethylamine based on Cucurbit[7]uril supramolecular assemblies

BACKGROUND

Phenethylamine (PEA) is a novel psychoactive substance that can cause agitation and hallucinations, posing a threat to human health. In this study, a N1@Q[7] supramolecular assembly with a robust fluorescent probe effect was prepared through the supramolecular self-assembly of cucurbit[7]uril (Q[7]) and a bromophenylpyridine derivative (N1).

RESULTS

In this supramolecular assembly, the isoquinoline moiety of N1 entered the cavity of Q[7], while the 4,4-bromophenylpyridyl moiety remained outside, forming a 1:1 inclusion complex. It was found that the addition of other amines did not significantly affect the fluorescence of the assembly, but the addition of PEA caused a notable decrease in fluorescence intensity and a red shift. N1@Q[7] demonstrated sensitive specificity and high selectivity to PEA. The principle is that PEA molecules, N1 molecules, and Q[7] form a synergistic ternary system. Based on this, the detection of PEA in real urine samples by N1@Q[7] was simulated.

SIGNIFFCANCE AND NOVELTY

The probe exhibited high selectivity in the presence of major components of real urine and enabled visual detection of PEA through fluorescence color change at different concentrations. This study provides a new fluorescent probe method for the detection of drugs and their metabolites.

Exploring structural features of sleep-enhancing peptides derived from casein hydrolysates by chemometrics and random forest methodology

Milk casein is regarded as source to release potential sleep-enhancing peptides. Although various casein hydrolysates exhibited sleep-enhancing activity, the underlying reason remains unclear. This study firstly revealed the structural features of potential sleep-enhancing peptides from casein hydrolysates analyzed through peptidomics and multivariate analysis. Additionally, a random forest model and a potential Tyr-based peptide library were established, and then those peptides were quantified to facilitate rapidly-screening. Our findings indicated that YP-, YI/L, and YQ-type peptides with 4-10 amino acids contributed more to higher sleep-enhancing activity of casein hydrolysates, due to their crucial structural features and abundant numbers. Furthermore, three novel strong sleep-enhancing peptides, YQKFPQY, YPFPGPIPN, and YIPIQY were screened, and their activities were validated in vivo. Molecular docking results elucidated the importance of the YP/I/L/Q- structure at the N-terminus of casein peptides in forming crucial hydrogen bond and π-alkyl interactions with His-102 and Asn-60, respectively in the GABAA receptor for activation.

The novel psychoactive substance 25E-NBOMe induces reward-related behaviors via dopamine D1 receptor signaling in male rodents

Novel psychoactive substances (NPSs) are new psychotropic drugs designed to evade substance regulatory policies. 25E-NBOMe (2-(4-ethyl-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine) has recently been identified as an NPS, and its recreational misuse has been reported to be rapidly increasing. However, the psychopharmacological effects and mechanisms of 25E-NBOMe have not been studied. We examined the abuse potential of 25E-NBOMe using the conditioned place preference in male mice and self-administration paradigms in male rats. Additionally, immunoblot assay, enzyme-linked immunosorbent assay, and microdialysis were used to determine the molecular effects of 25E-NBOMe in the nucleus accumbens (NAc). Our data demonstrated that 25E-NBOMe induces conditioned place preference, and the dopaminergic signaling in the NAc mediates these. Following 25E-NBOMe administration, expression of dopamine transporter and dopamine D1 receptor (D1DR) were enhanced in the NAc of male mice, and NAc dopamine levels were reduced in both male mice and rats. Induction of intracellular dopaminergic pathways, DARPP32, and phosphorylation of CREB in the NAc of male mice was also observed. Significantly, pharmacological blockade of D1DR or chemogenetic inhibition of D1DR-expressing medium spiny neurons in the NAc attenuated 25E-NBOMe-induced conditioned place preference in male mice. We also examined the hallucinogenic properties of 25E-NBOMe using the head twitch response test in male mice and found that this behavior was mediated by serotonin 2A receptor activity. Our findings demonstrate that D1DR signaling may govern the addictive potential of 25E-NBOMe. Moreover, our study provides new insights into the potential mechanisms of substance use disorder and the improvement of controlled substance management.

Brain Microdialysis Coupled to LC-MS/MS Revealed That CVT-10216, a Selective Inhibitor of Aldehyde Dehydrogenase 2, Alters the Neurochemical and Behavioral Effects of Methamphetamine

Methamphetamine (MA), a potent central nervous system stimulant, mainly affects the brain dopaminergic and serotoninergic systems. Monoamine oxidase, catechol-O-methyltransferase, and aldehyde dehydrogenase 2 (ALDH2) are important enzymes in the metabolism of dopamine (DA) and serotonin (5-HT); however, the role of ALDH2 in MA addiction remains unclear. This study focused on the real-time changes in DA, 5-HT, and their metabolites, including 3,4-dihydroxyphenylacetic aldehyde and salsolinol, which are metabolites directly related to ALDH2, to examine the effects of the inhibition of ALDH2 on hyperlocomotion induced by MA. Locomotor activity was evaluated in rats after administration of MA and/or CVT-10216 (a selective ALDH2 inhibitor). Moreover, the simultaneous quantification of DA, 5-HT, and their metabolites in brain microdialysates of the rats was performed using a derivatization-assisted LC-MS/MS method after full validation. The validation results proved the method to be selective, sensitive, accurate, and precise, with acceptable linearity within calibration ranges. Intraperitoneal (i.p.) administration of 10 or 20 mg/kg of CVT-10216 significantly decreased MA-induced hyperlocomotion (1 mg/kg, i.p.). The analytical results of rat brain microdialysates demonstrated that the administration of CVT-10216 significantly downregulated DA levels, which were increased upon exposure to MA. Moreover, the increase in 3-methoxytyramine levels following coadministration of CVT-10216 and MA could play a potential role in antagonizing the hyperlocomotion induced by MA. All of these findings suggest that the inhibition of ALDH2 protects against MA-induced hyperlocomotion and has therapeutic potential in MA addiction.

The psychoactive aminoalkylbenzofuran derivatives, 5-APB and 6-APB, mimic the effects of 3,4-methylenedioxyamphetamine (MDA) on monoamine transmission in male rats

RATIONALE

The nonmedical use of new psychoactive substances (NPS) is a worldwide public health concern. The so-called "benzofury" compounds, 5-(2-aminopropyl)benzofuran (5-APB) and 6-(2-aminopropyl)benzofuran (6-APB), are NPS with stimulant-like properties in human users. These substances are known to interact with monoamine transporters and 5-HT receptors in transfected cells, but less is known about their effects in animal models.

METHODS

Here, we used in vitro monoamine transporter assays in rat brain synaptosomes to characterize the effects of 5-APB and 6-APB, together with their N-methyl derivatives 5-MAPB and 6-MAPB, in comparison with 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA). In vivo neurochemical and behavioral effects of 5-APB (0.3 and 1.0 mg/kg, i.v.) and 6-APB (0.3 and 1.0 mg/kg, i.v.) were assessed in comparison with MDA (1.0 and 3.0 mg/kg, i.v.) using microdialysis sampling in the nucleus accumbens of conscious male rats.

RESULTS

All four benzofuran derivatives were substrate-type releasers at dopamine transporters (DAT), norepinephrine transporters (NET), and serotonin transporters (SERT) with nanomolar potencies, similar to the profile of effects produced by MDA and MDMA. However, the benzofurans were at least threefold more potent than MDA and MDMA at evoking transporter-mediated release. Like MDA, both benzofurans induced dose-related elevations in extracellular dopamine and serotonin in the brain, but benzofurans were more potent than MDA. The benzofuran derivatives also induced profound behavioral activation characterized by forward locomotion which lasted for at least 2 h post-injection.

CONCLUSIONS

Overall, benzofurans are more potent than MDA in vitro and in vivo, producing sustained stimulant-like effects in rats. These data suggest that benzofuran-type compounds may have abuse liability and could pose risks for adverse effects, especially if used in conjunction with abused drugs or medications which enhance monoamine transmission in the brain.