A new designer drug 5F-ADB activates midbrain dopaminergic neurons but not serotonergic neurons

Analytical findings in a non-fatal intoxication with the synthetic cannabinoid 5F-ADB (5F-MDMB-PINACA): a case report

The case report centres on analytical findings from a spice sample (mixed with tobacco (as a cigarette) for consumption), and its corresponding plasma sample, smoked by a 31-year-old man who was attended by emergency services following collapse. The man was fully conscious and cooperative during initial medical treatment. Suddenly, he suffered a complete loss of self-control, whereupon the police was notified. The man encountered the police officers when exiting the apartment, at which point he threatened them with clenched fists and reached for a plant bucket in order to strike out in the direction of the officers. At the trial, he described himself as confused and as being completely overwhelmed, having lost self-control, suffered a panic attack and “just wanted to get out the situation”. Furthermore, he stated that he had no recollection of the incident. He feared death due to palpitations, heart pain, dizziness and repetitive anxiety states. Routine systematic as well as extended toxicological analysis of the plasma sample, taken approximately 2 h after the incident, confirmed the use of cannabis and spice. Plasma concentrations of THC, OH-THC and THC-COOH were 8.0 μg/L, 4.0 μg/L and 147 μg/L, respectively. Furthermore, analysis confirmed uptake of 5F-ADB (5F-MDMB-PINACA) via detection of both 5F-ADB and the 5F-ADB N-(5-OH-pentyl) metabolite. The spice sample additionally contained 5F-MDMB-PICA, which was not detected in the plasma sample. A differentiation between a possible co-use and a recent use of cannabis was not possible. In summary, this case once more underlines the health risks of spice use.

Pharmacology and adverse effects of new psychoactive substances: synthetic cannabinoid receptor agonists

Over the last decade, new psychoactive substances (NPS) have continuously been the focus of the international society since their emergence on the illicit drug market. NPS can be classified into six groups including; synthetic cannabinoid receptor agonists (SCRAs), stimulants, opioids, dissociatives, sedatives/hypnotics, and classic hallucinogens with psychoactive effects. These are sold as "herbal incense," "bath salts," "legal highs," and "research chemicals". They can be synthesized easily with slight changes in the chemical moieties of known psychoactive substances. NPS are sold worldwide via on- and off-line markets without proper scientific evaluation regarding their safety or harmfulness. Abuse of NPS poses a serious public health issue, and systematic studies on their adverse effects are lacking. Therefore, it would be meaningful to collect currently available data in order to understand NPS and to establish viable solutions to cope with the various health issues related to them. In this article, we reviewed the general pharmacological characteristics, recent findings, and adverse effects of representative NPS; SCRAs. SCRAs are known as the most commonly abused NPS. Most SCRAs, cannabinoid receptor 1 and cannabinoid receptor 2 agonists, are often associated with severe toxicities, including cardiotoxicity, immunotoxicity, and even death, unlike natural cannabinoid Δ⁹-Tetrahydrocannabinol.

Advances in D-Amino Acids in Neurological Research

D-amino acids have been known to exist in the human brain for nearly 40 years, and they continue to be a field of active study to today. This review article aims to give a concise overview of the recent advances in D-amino acid research as they relate to the brain and neurological disorders. This work has largely been focused on modulation of the N-methyl-D-aspartate (NMDA) receptor and its relationship to Alzheimer’s disease and Schizophrenia, but there has been a wealth of novel research which has elucidated a novel role for several D-amino acids in altering brain chemistry in a neuroprotective manner. D-amino acids which have no currently known activity in the brain but which have active derivatives will also be reviewed.

Designer drugs: a medicinal chemistry perspective (II)

During 2012-2018, the clandestine manufacture of new psychoactive substances (NPS) designed to circumvent substance control regulations increased exponentially worldwide, with concomitant increase in fatalities. This review focuses on three compound classes identified as synthetic opioids, synthetic amphetamines, and synthetic cannabinoids and highlights the medicinal chemistry precedents utilized by clandestine laboratories to develop new NPS with increased brain penetration, longer duration of action, and greater potency. Chemical approaches to illicit drug abuse treatment options, particularly for opioid use disorder, are also discussed.

Identification and Quantification of 5-Fluoro ADB and the 5-Fluoro ADB Ester Hydrolysis Metabolite in Postmortem Blood Samples by LC–MS/MS

5-Fluoro ADB, also known as 5-fluoro MDMB-PINACA, is a potent synthetic cannabinoid that is an agonist to the human cannabinoid CB1 and CB2 receptors. Adverse physiological and psychological effects that have resulted in hospitalization and/or death have been associated with 5-Fluoro ADB use. In addition, analytical confirmation of 5-Fluoro ADB use has been reported in both forensic human performance toxicology and postmortem cases. An analytical method for the identification and quantification of 5-fluoro ADB and the 5-fluoro ADB ester hydrolysis metabolite in human blood samples by liquid chromatography–tandem mass spectrometry was created and validated. The linear range of this assay was determined to be 0.01–10 ng/mL for 5-fluoro ADB and 10–500 ng/mL for the 5-fluoro ADB ester hydrolysis metabolite. The method met both precision and accuracy requirements. Endogenous and exogenous interferences were not observed. Ion suppression exceeding 25% was observed for 5-fluoro ADB. However, additional experiments were performed to ensure that the observed suppression did not affect other method validation parameters such as limit of detection and accuracy. Blood samples from 36 postmortem cases were analyzed utilizing this methodology. The average blood concentration of 5-fluoro ADB was 0.29 ng/mL in central blood specimens and 0.05 ng/mL in peripheral blood specimens. The average blood concentration of the 5-fluoro ADB ester hydrolysis metabolite was 49 ng/mL in central blood specimens and 21 ng/mL in peripheral blood specimens. A serum sample was also analyzed and had a serum concentration of 0.12 ng/mL for 5-fluoro ADB and 42 ng/mL for the 5-fluoro ADB ester hydrolysis metabolite. As the concentration of the 5-fluoro ADB ester hydrolysis metabolite was found at a greater concentration than that of 5-fluoro ADB, this metabolite may be a useful marker to monitor in an attempt to confirm 5-fluoro ADB use in toxicological investigations.

Forty-Three Fatalities Involving the Synthetic Cannabinoid, 5-Fluoro-ADB: Forensic Pathology and Toxicology Implications

Forty-three fatalities involving the potent synthetic cannabinoid, 5-Fluoro-ADB, are summarized. For each case, a description of the terminal event, autopsy findings, cause of death, qualitative identification of 5-Fluoro-ADB and its ester hydrolysis metabolite, 5-Fluoro-ADB metabolite 7, in urine, and the quantitative values obtained in the blood specimens are outlined. Central blood concentrations ranged from 0.010 to 2.2 ng/mL for 5-Fluoro-ADB and 2.0 to 166 ng/mL for 5-Fluoro-ADB metabolite 7. Peripheral blood concentrations ranged from 0.010 to 0.77 ng/mL and 2.0 to 110 ng/mL for 5-Fluoro-ADB and 5-Fluoro-ADB metabolite 7, respectively. The majority of cases resulted in central to peripheral blood concentration ratios greater than 1 for 5-Fluoro-ADB (58%) and 5-Fluoro-ADB metabolite 7 (71%) suggesting that postmortem redistribution occurs to some extent. Combining the increased cardiac weight and/or gastric volume and toxicology data identifying 5-Fluoro-ADB, it is hypothesized that abuse of this substance may precipitate a dysrhythmia and cause sudden death.

Cannabinoid-like effects of five novel carboxamide synthetic cannabinoids

A new generation of novel cannabinoid compounds have been developed as marijuana substitutes to avoid drug control laws and cannabinoid blood tests. 5F-MDMB-PINACA (also known as 5F-ADB, 5F-ADB-PINACA), MDMB-CHIMICA, MDMB-FUBINACA, ADB-FUBINACA, and AMB-FUBINACA (also known as FUB-AMB, MMB-FUBINACA) were tested for in vivo cannabinoid-like effects to assess their abuse liability. Locomotor activity in mice was tested to screen for locomotor depressant effects and to identify behaviorally-active dose ranges and times of peak effect. Discriminative stimulus effects were tested in rats trained to discriminate Δ⁹-tetrahydrocannabinol (3 mg/kg, 30-min pretreatment). 5F-MDMB-PINACA (ED₅₀ = 1.1 mg/kg) and MDMB-CHIMICA (ED₅₀ = 0.024 mg/kg) produced short-acting (30 min) depression of locomotor activity. ADB-FUBINACA (ED₅₀ = 0.19 mg/kg), and AMB- FUBINACA (ED₅₀ = 0.19 mg/kg) depressed locomotor activity for 60-90 min; whereas MDMB-FUBINACA (ED₅₀ = 0.04 mg/kg) depressed locomotor activity for 150 min. AMB-FUBINACA produced tremors at the highest dose tested. 5F-MDMB-PINACA (ED₅₀ = 0.07), MDMB-CHIMICA (ED₅₀ = 0.01 mg/kg), MDMB-FUBINACA (ED₅₀ = 0.051 mg/kg), ADB-FUBINACA (ED₅₀ = 0.075 mg/kg) and AMB-FUBINACA (ED₅₀ = 0.029) fully substituted for the discriminative stimulus effects of Δ⁹-THC following 15-min pretreatment. All 5 compounds decreased locomotor activity and produced discriminative stimulus effects similar to those of Δ⁹-THC, which suggests they may have abuse liability similar to that of Δ⁹-THC. AMB-FUBINACA may have an increased risk of toxicities in recreational users.

Psychosis and synthetic cannabinoids

Synthetic cannabinoid (SC) products have gained popularity as abused drugs over the past decade in many countries. The SCs broadly impact psychological state (e.g., mood, suicidal thoughts and psychosis) and physiological functions (e.g., cardiovascular, gastrointestinal and urinary). This review is about the effects of SCs on psychotic symptoms in clinical settings and the potentially relevant chemistry and mechanisms of action for SCs. Induction of psychotic symptoms after consuming SC products were reported, including new-onset psychosis and psychotic relapses. The role of SCs in psychosis is more complex than any single chemical component might explain, and these effects may not be a simple extension of the typical effects of cannabis or natural cannabinoids.

The synthetic cannabinoid 5F-AMB changes the balance between excitation and inhibition of layer V pyramidal neurons in the mouse medial prefrontal cortex

RATIONALE

5F-AMB is one of the synthetic cannabinoids (SCs) designed to potentiate the ability to activate cannabinoid 1 (CB1) receptors and is abused worldwide. Although inhalation of 5F-AMB elicits serious adverse effects including impaired memory and consciousness, it is not known whether and how 5F-AMB affects the activity of pyramidal neurons in the medial prefrontal cortex (mPFC), a brain region associated with higher functions such as memory and cognition.

OBJECTIVES

In the present study, we examined the effects of 5F-AMB on mPFC layer V (L5) pyramidal neurons using in vitro whole-cell patch-clamp recordings.

RESULTS

Bath application of 5F-AMB attenuated the frequency but not the amplitude of spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs). The attenuating effects of 5F-AMB were abolished by the CB1 receptor antagonist AM251. 5F-AMB also attenuated the frequency of miniature EPSCs and IPSCs recorded in the presence of tetrodotoxin. Moreover, the extent of attenuating effects of 5F-AMB on stimulus-evoked EPSCs was significantly larger than that on evoked IPSCs.

CONCLUSIONS

These findings suggest that 5F-AMB attenuates both excitatory and inhibitory transmission in mPFC L5 pyramidal neurons via the activation of CB1 receptors located in presynaptic terminals. Further, the net impact of 5F-AMB on L5 pyramidal neurons is inhibition due to the change in balance between excitation and inhibition. This inhibitory effect might at least partly contribute to the expression of the adverse effects induced by 5F-AMB inhalation.

Motor vehicle collisions caused by the 'super-strength' synthetic cannabinoids, MAM-2201, 5F-PB-22, 5F-AB-PINACA, 5F-AMB and 5F-ADB in Japan experienced from 2012 to 2014

From 2012 to 2014 in Japan, 214 cases of motor vehicle collisions were attributed to the use of illegal drugs. In 93 out of 96 investigated cases, the causative agents were a variety of synthetic cannabinoids (SCs). These SCs can be classified into three groups according to the lineage of the chemical structures: (1) naphthoyl indoles, such as MAM-2201, (2) quinolinyl ester indoles, such as 5F-PB-22, and (3) indazole carboxamides, such as 5F-AB-PINACA, 5F-AMB, and 5F-ADB. These SCs became available sequentially with increasing cannabinoid CB₁ agonist potencies and reached a nationwide outbreak in the summer of 2014. They caused acute intoxication with impaired consciousness, anterograde amnesia (impaired memory), catalepsy with muscle rigidity, tachycardia, and vomiting or drooling soon after smoking. Drivers who had abused one of these SCs might unexpectedly experience the acute intoxication that caused uncontrolled driving. These SCs were generally difficult to detect from body fluid samples. It is thought that the highly lipophilic SCs disappear from the blood via rapid degradation by liver enzymes and selective accumulation into adipose tissues. Thus, much effort should be directed to the development of fast and sensitive chemical detection of the drug usage.