Analysis of Relationships between DAT1 Polymorphism Variants, Personality Dimensions, and Anxiety in New Psychoactive Substance (Designer Drug) (NPS) Users

The use of ‘new psychoactive substances’ appears to be increasingly common. The aim of this study was to examine biological and personality determinants in individuals who choose to use these substances, which may help in the prevention and treatment of psychoactive substance use disorders. The study group consisted of 374 male volunteers; all were users of ‘new psychoactive substances’ (NPS). The NPS users were recruited after they had abstained—for at least 3 months—from any substance of abuse in addiction treatment facilities. The NPS patients and the control subjects were examined by a psychiatrist using the Mini-International Neuropsychiatric Interview (M.I.N.I.), the NEO Five-Factor Personality Inventory (NEO-FFI), and the State-Trait Anxiety Inventory (STAI) scales. The real-time PCR method was used for genotyping. When we compared the controls with the study group, statistically significant interactions were found between DAT1 polymorphism, neuroticism, and NPS use. NPS use and DAT1 polymorphism were associated with a higher level of neuroticism on the NEO-FFI scale. The study group of NPS users showed a higher severity of anxiety symptoms, both in terms of trait and state, compared to the control group. The results may support the idea that neuroticism and anxiety correlate strongly with coping motives for using NPS.

Chemogenetic modulation of sensory neurons reveals their regulating role in melanoma progression

Sensory neurons have recently emerged as components of the tumor microenvironment. Nevertheless, whether sensory neuronal activity is important for tumor progression remains unknown. Here we used Designer Receptors Exclusively Activated by a Designer Drug (DREADD) technology to inhibit or activate sensory neurons’ firing within the melanoma tumor. Melanoma growth and angiogenesis were accelerated following inhibition of sensory neurons’ activity and were reduced following overstimulation of these neurons. Sensory neuron-specific overactivation also induced a boost in the immune surveillance by increasing tumor-infiltrating anti-tumor lymphocytes, while reducing immune-suppressor cells. In humans, a retrospective in silico analysis of melanoma biopsies revealed that increased expression of sensory neurons-related genes within melanoma was associated with improved survival. These findings suggest that sensory innervations regulate melanoma progression, indicating that manipulation of sensory neurons’ activity may provide a valuable tool to improve melanoma patients’ outcomes.

Identification and structural characterization of three psychoactive substances, phenylpiperazines (pBPP and 3,4-CFPP) and a cocaine analogue (troparil), in collected samples

Purpose New psychoactive substances (NPSs) still appear on the market, mainly due to their legal status. This situation indicates and alarms that permanent recognition of the designer drug scene should be conducted. In this paper, we describe the detection of three psychoactive substances in samples collected from drug users. Methods Qualitative characterization was performed using liquid chromatography–high-resolution tandem mass spectrometry with a quadrupole time-of-flight analyzer, gas chromatography with mass spectrometry and nuclear magnetic resonance spectroscopy. Results In this study, we reported the detection and structural elucidation of three psychoactive substances: 1-(4-bromophenyl)piperazine (pBPP), 1-(3-chloro-4-fluorophenyl)piperazine (3,4-CFPP) and methyl 8-methyl-3-phenyl-8-azabicyclo[3.2.1]octane-4-carboxylate (troparil). Conclusions To the best of our knowledge, this is the first report that presents an identification methodology for these substances found in illegal products. Comprehensive characterization of the NPSs presented in this paper facilitates their detection and identification by forensic and clinical laboratories.

Behavioral and Neurostructural changes associated with Chronic Amygdala Hyperactivation

Background: The amygdala (AMY) is a key brain region of the limbic system that plays a critical role in emotion processing and stress response. Functional magnetic resonance imaging (fMRI) studies identified abnormal AMY activation in psychiatric illnesses including major depressive disorder (MDD). Stress exposure is a major precipitating factor of MDD episodes which are associated with AMY hyperactivity. Preclinical studies using of pharmacologic, opto- and chemogenetic approaches to activate AMY neurons have consistently demonstrated that acute AMY hyperactivation induces anxiety-like behaviors in mice. However, it remains unknown if chronic hyperactivation of the amygdala (cHOA) is sufficient to induce chronic stress-like deficits or is a susceptibility factor for chronic stress-induced behavioral, volumetric and synaptic deficits. Methods: Using designer receptor exclusively activated by designer drug (DREADD) approach, basolateral amygdala (BLA) neurons of Camk2a-cre mice infected with a virus driving the expression of the Gq-coupled DREADD were activated with clozapine-N-oxide (in drink water for 5 weeks). Mice were then exposed to chronic restraint stress (CRS; 1X/day for 1hr) for 2 weeks. All mice were behaviorally assessed in the Phenotyper (PT), and sucrose consumption tests (SCT) each week and in the novelty supressed feeding (NSF, once at the end of the experiment). Animals were then perfused for ex vivo-MRI and puncta density analysis. Results: We found that mice with cHOA displayed a progressive increase in baseline anxiety-like deficits in the PT test and slightly more marked deficits following CRS compared to controls, but not statistically different from animals subjected to CRS alone. Also, cHOA did not exacerbate CRS effect in the NSF. No significant cAH effect was found in the SCT before or after CRS. MRI analysis revealed no statistical charges between groups, while increased synaptic puncta density was found in cHOA mice subjected to CRS compared to cHOA or CRS alone. Conclusion: We demonstrate that cAH is sufficient to induce anxiety and may exacerbate CRS effects on anxiety and synaptic measures. Results also suggest that cHOA was not sufficient to induce depressive-like behavior and was not a vulnerability factor for stress-induced depressive-like behavior in mice. Altogether, our findings imply that a strong causal link between AMY hyperactivity and elevated anxiety, but not depressive-like behaviors and provide critical information to clinical research focused on using AMY activity level as a biomarker in stress-related illnesses.

In vivo cardiopulmonary impact of skeletal M3Dq DREADD expression: a pilot study

The muscarinic M3 receptor (M3R) is implicated in cardiopulmonary control and many other peripheral physiologic functions. Previous observations report mortality in mice expressing a Gq-linked designer G-protein coupled receptor (Dq) selectively in striated muscle, while M3Dq DREADD (Designer Receptor Exclusively Activated by Designer Drug), selectively expressed in skeletal muscle (SKM) impacts glucose metabolism. We investigated whether activation of SKM M3Dq impacts cardiopulmonary function. Heart rate (HR), body temperature (Tb) and locomotor activity (ACT) were measured in 4 conscious, chronically instrumented M3Dq DREADD mice and 4 wildtype controls. Circadian values of HR, BT and ACT were not different between genotypes (p > 0.05). Activation of the M3Dq DREADD by clozapine N-oxide (CNO; 0.1 mg/kg) resulted in: a significant drop in heart rate, 2 h after injection, compared with a time-matched baseline control period from the same animals (460 ± 28 vs. 532 ± 6, p < 0.05), significantly lower ACT compared to the baseline control (p < 0.05) and reduced pulmonary minute ventilation compared to pre-CNO control (p < 0.05). M3Dq DREADD activation did not cause bronchoconstriction (separate protocol), however, there was a concomitant reduction in HR, Tb and ventilation, accompanied by cardiac arrhythmias. We speculate that reductions in Tb, HR and ventilation reflect a mechanistic link between SKM Gq signaling and the metabolic responses associated with the initiation of torpor. Supported by the Canadian Institutes of Health Research (CIHR MOP-81211).

The Vaporization Enthalpy and Vapor Pressure of (±) N-Ethyl Amphetamine by Correlation Gas Chromatography

The vaporization enthalpy, and vapor pressure as a function of temperature of N-ethylamphetamine, a substance used in the 1950s as an appetite suppressant and more currently abused as a designer drug, is reported. Its physical properties are compared to those of S (+)-N-methamphetamine, a substance whose physiological properties it mimics. A vaporization enthalpy of (62.4 ± 4.4) kJ·mol−1 and vapor pressure of (19 ± 11) Pa at T = 298.15 K has been evaluated by correlation gas chromatography. Results are compared to estimated values and to the limited amount of experimental property data available.

Chemogenetic Activation of Feed-Forward Inhibitory Parvalbumin-Expressing Interneurons in the Cortico-Thalamocortical Network During Absence Seizures

Parvalbumin-expressing (PV+) interneurons are a subset of GABAergic inhibitory interneurons that mediate feed-forward inhibition (FFI) within the cortico-thalamocortical (CTC) network of the brain. The CTC network is a reciprocal loop with connections between cortex and thalamus. FFI PV+ interneurons control the firing of principal excitatory neurons within the CTC network and prevent runaway excitation. Studies have shown that generalized spike-wave discharges (SWDs), the hallmark of absence seizures on electroencephalogram (EEG), originate within the CTC network. In the stargazer mouse model of absence epilepsy, reduced FFI is believed to contribute to absence seizure genesis as there is a specific loss of excitatory α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) at synaptic inputs to PV+ interneurons within the CTC network. However, the degree to which this deficit is directly related to seizure generation has not yet been established. Using chemogenetics and in vivo EEG recording, we recently demonstrated that functional silencing of PV+ interneurons in either the somatosensory cortex (SScortex) or the reticular thalamic nucleus (RTN) is sufficient to generate absence-SWDs. Here, we used the same approach to assess whether activating PV+ FFI interneurons within the CTC network during absence seizures would prevent or reduce seizures. To target these interneurons, mice expressing Cre recombinase in PV+ interneurons (PV-Cre) were bred with mice expressing excitatory Gq-DREADD (hM3Dq-flox) receptors. An intraperitoneal dose of pro-epileptic chemical pentylenetetrazol (PTZ) was used to induce absence seizure. The impact of activation of FFI PV+ interneurons during seizures was tested by focal injection of the “designer drug” clozapine N-oxide (CNO) into either the SScortex or the RTN thalamus. Seizures were assessed in PVCre/Gq-DREADD animals using EEG/video recordings. Overall, DREADD-mediated activation of PV+ interneurons provided anti-epileptic effects against PTZ-induced seizures. CNO activation of FFI either prevented PTZ-induced absence seizures or suppressed their severity. Furthermore, PTZ-induced tonic-clonic seizures were also reduced in severity by activation of FFI PV+ interneurons. In contrast, administration of CNO to non-DREADD wild-type control animals did not afford any protection against PTZ-induced seizures. These data demonstrate that FFI PV+ interneurons within CTC microcircuits could be a potential therapeutic target for anti-absence seizure treatment in some patients.