The Abuse Potential of α-Piperidinopropiophenone (PIPP) and α-Piperidinopentiothiophenone (PIVT), Two New Synthetic Cathinones with Piperidine Ring Substituent

New designer phenethylamines 2C-C and 2C-P have abuse potential and induce neurotoxicity in rodents

2C (2C-x) is the general name for the family of phenethylamines containing two methoxy groups at the 2 and 5 positions of the benzene ring. The abuse of 2C family drugs has grown rapidly, although the abuse potential and neurotoxic properties of 2C drugs have not yet been fully investigated. In this study, we investigated the abuse potential and neurotoxicity of 4-chloro-2,5-dimethoxyphenethylamine (2C-C) and 2,5-dimethoxy-4-propylphenethylamine (2C-P). We found that 2C-C and 2C-P produced conditioned place preference in a dose-dependent manner in mice, and increased self-administration in rats, suggesting that 2C-C and 2C-P have abuse potential. To investigate the neurotoxicity of 2C-C and 2C-P, we examined motor performance and memory impairment after high doses of 2C-C and 2C-P. High doses of 2C-C and 2C-P decreased locomotor activity, rota-rod performance, and lower Y-maze test, novel objective recognition test, and passive avoidance test scores. We also observed that 2C-C and 2C-P affected expression levels of the D1 dopamine receptor, D2 dopamine receptor, dopamine transporter, and phospho-dopamine transporter in the nucleus accumbens and the medial prefrontal cortex, and increased c-Fos immuno-positive cells in the nucleus accumbens. Moreover, high doses of 2C-C and 2C-P induced microglial activation, which is involved in the inflammatory reaction in the striatum. These results suggest that 2C-C and 2C-P have abuse potential by affecting dopaminergic signaling and induce neurotoxicity via initiating neuroinflammation at high doses.

The Atxn7-overexpressing mice showed hyperactivity and impulsivity which were ameliorated by atomoxetine treatment: A possible animal model of the hyperactive-impulsive phenotype of ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous neurodevelopmental disorder characterized by varying levels of hyperactivity, inattention, and impulsivity. Patients with ADHD are often classified as (1) predominantly hyperactive-impulsive, (2) predominantly inattentive, and (3) combined type. There is a growing interest in developing specific animal models that would recapitulate specific clinical forms of ADHD, with the goal of developing specific therapeutic strategies. In our previous study, we have identified Ataxin-7 (Atxn7) as a hyperactivity-associated gene. Here, we generated Atxn7 overexpressing (Atxn7 OE) mice to investigate whether the increased Atxn7 expression in the brain correlates with ADHD-like behaviors. Quantitative real-time polymerase chain reaction and immunofluorescence confirmed overexpression of the Atxn7 gene and protein in the prefrontal cortex (PFC) and striatum (STR) of the Atxn7 OE mice. The Atxn7 OE mice displayed hyperactivity and impulsivity, but not inattention. Interestingly, treatment with the ADHD drug, atomoxetine (3 mg/kg, intraperitoneal), attenuated ADHD-like behaviors and reduced Atxn7 gene expression in the PFC and STR of these mice. These findings suggest that Atxn7 plays a role in the pathophysiology of ADHD, and that the Atxn7 OE mice can be used as an animal model of the hyperactive-impulsive phenotype of this disorder. Although confirmatory studies are warranted, the present study provides valuable information regarding the potential genetic underpinnings of ADHD.

Blockade of TRPV1 Inhibits Methamphetamine-induced Rewarding Effects

Methamphetamine (MAP) is the most widely used psychostimulant in the world, but the exact mechanisms underlying MAP addiction are not yet fully understood. Recent studies have identified the distribution of TRPV1 in several brain regions that are related to drug addiction, including nucleus accumbens (NAc) and dorsal striatum (DSt). In the present study, we performed conditioned place preference (CPP) and self-administration tests to examine the effects of capsazepine (CPZ) and SB366791 (SB) on MAP reward. We found that both CPZ and SB significantly inhibited MAP-induced CPP and self-administration; in contrast, TRPV1 knock-out (KO) mice did not develop MAP-induced CPP. Real-time RT-PCR, Western blot and quantitative autoradiographic tests showed up-regulation of TRPV1 mRNA and protein expression in the NAc and/or DSt regions of mice exhibiting MAP-induced CPP. In addition, an in vivo microdialysis experiment showed that CPZ dramatically reduced dopamine (DA) levels in the NAc region of MAP-treated mice. Furthermore, attenuated dopamine transporter (DAT) binding levels in the NAc and DSt regions of MAP-induced CPP mice were reversed by CPZ. Together, these data suggest that TRPV1 plays an important role in MAP reward via the modulation of DA release and DAT density, thereby providing a novel therapeutic target for MAP addiction.

Synthetic Cathinone and Cannabinoid Designer Drugs Pose a Major Risk for Public Health

As part of an increasing worldwide use of designer drugs, recent use of compounds containing cathinones and synthetic cannabinoids is especially prevalent. Here, we reviewed current literature on the prevalence, epidemiology, bio-behavioral effects, and detection of these compounds. Gender differences and clinical effects will also be examined. Chronic use of synthetic cathinone compounds can have major effects on the central nervous system and can induce acute psychosis, hypomania, paranoid ideation, and delusions, similar to the effects of other better-known amphetamine-type stimulants. Synthetic cannabinoid products have effects that are somewhat similar to those of natural cannabis but more potent and long-lasting than THC. Some of these compounds are potent and dangerous, having been linked to psychosis, mania, and suicidal ideation. Novel compounds are developed rapidly and new screening techniques are needed to detect them as well as a rigorous regulation and legislation reinforcement to prevent their distribution and use. Given the rapid increase in the use of synthetic cathinones and cannabinoid designer drugs, their potential for dependence and abuse, and harmful medical and psychiatric effects, there is a need for research and education in the areas of prevention and treatment.