Acute DOB and PMA Administration Impairs Motor and Sensorimotor Responses in Mice and Causes Hallucinogenic Effects in Adult Zebrafish

The drastic increase in hallucinogenic compounds in illicit drug markets of new psychoactive substances (NPS) is a worldwide threat. Among these, 2, 5-dimetoxy-4-bromo-amphetamine (DOB) and paramethoxyamphetamine (PMA; marketed as "ecstasy") are frequently purchased on the dark web and consumed for recreational purposes during rave/dance parties. In fact, these two substances seem to induce the same effects as MDMA, which could be due to their structural similarities. According to users, DOB and PMA share the same euphoric effects: increasing of the mental state, increasing sociability and empathy. Users also experienced loss of memory, temporal distortion, and paranoia following the repetition of the same thought. The aim of this study was to investigate the effect of the acute systemic administration of DOB and PMA (0.01-30 mg/kg; i.p.) on motor, sensorimotor (visual, acoustic, and tactile), and startle/PPI responses in CD-1 male mice. Moreover, the pro-psychedelic effect of DOB (0.075-2 mg/kg) and PMA (0.0005-0.5 mg/kg) was investigated by using zebrafish as a model. DOB and PMA administration affected spontaneous locomotion and impaired behaviors and startle/PPI responses in mice. In addition, the two compounds promoted hallucinatory states in zebrafish by reducing the hallucinatory score and swimming activity in hallucinogen-like states

Neurochemical and Behavioral Profiling in Male and Female Rats of the Psychedelic Agent 25I-NBOMe

4-Iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (25I-NBOMe), commonly called "N-Bomb," is a synthetic phenethylamine with psychedelic and entactogenic effects; it was available on the Internet both as a legal alternative to lysergic acid diethylamide (LSD) and as a surrogate of 3,4-methylenedioxy-methamphetamine (MDMA), but now it has been scheduled among controlled substances. 25I-NBOMe acts as full agonist on serotonergic 5-HT2A receptors. Users are often unaware of ingesting fake LSD, and several cases of intoxication and fatalities have been reported. In humans, overdoses of "N-Bomb" can cause tachycardia, hypertension, seizures, and agitation. Preclinical studies have not yet widely investigated the rewarding properties and behavioral effects of this compound in both sexes. Therefore, by in vivo microdialysis, we evaluated the effects of 25I-NBOMe on dopaminergic (DA) and serotonergic (5-HT) transmissions in the nucleus accumbens (NAc) shell and core, and the medial prefrontal cortex (mPFC) of male and female rats. Moreover, we investigated the effect of 25I-NBOMe on sensorimotor modifications as well as body temperature, nociception, and startle/prepulse inhibition (PPI). We showed that administration of 25I-NBOMe affects DA transmission in the NAc shell in both sexes, although showing different patterns; moreover, this compound causes impaired visual responses in both sexes, whereas core temperature is heavily affected in females, and the highest dose tested exerts an analgesic effect prominent in male rats. Indeed, this drug is able to impair the startle amplitude with the same extent in both sexes and inhibits the PPI in male and female rats. Our study fills the gap of knowledge on the behavioral effects of 25I-NBOMe and the risks associated with its ingestion; it focuses the attention on sex differences that might be useful to understand the trend of consumption as well as to recognize and treat intoxication and overdose symptoms

Potential of the zebrafish model for the forensic toxicology screening of NPS: A comparative study of the effects of APINAC and methiopropamine on the behavior of zebrafish larvae and mice

Abstract The increased diffusion of the so-called novel psychoactive substances (NPS) and their continuous change in structure andconceivably activity has led to the need of a rapid screening method to detect their biological effects as early as possible after their appearance in the market. This problem is very felt in forensic pathology and toxicology, so the preclinical study is fundamental in the approach to clinical and autopsy cases of difficult interpretation intoxication. Zebrafish is a high-throughput suitable model to rapidly hypothesize potential aversive or beneficial effects of novel molecules. In the present study, we measured and compared the behavioral responses to two novel neuroactive drugs, namely APINAC, a new cannabimimetic drug, and methiopropamine (MPA), a methamphetamine-like compound, on zebrafish larvae (ZL) and adult mice. By using an innovative statistical approach (general additive models), it was found that the spontaneous locomotor activity was impaired by the two drugs in both species: the disruption extent varied in a dose-dependent and time-dependent manner. Sensorimotor function was also altered: i) the visual object response was reduced in mice treated with APINAC, whereas it was not after exposure to MPA; ii) the visual placing responses were reduced after treatment with both NPS in mice. Furthermore, the visual motor response detected in ZL showed a reduction after treatment with APINAC during light-dark and dark-light transition. The same pattern was found in the MPA exposed groups only at the dark-light transition, while at the transition from light to dark, the individuals showed an increased response. In conclusion, the present study highlighted the impairment of spontaneous motor and sensorimotor behavior induced by MPA and APINAC administration in both species, thus confirming the usefulness of ZL as a model for a rapid behavioural-based drug screening

Worsening of the Toxic Effects of (±) Cis -4,4′-DMAR Following Its Co-Administration with (±) Trans -4,4′-DMAR: Neuro-Behavioural, Physiological, Immunohistochemical and Metabolic Studies in Mice

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/4.0/).4,4’-Dimethylaminorex (4,4’-DMAR) is a new synthetic stimulant, and only a little information has been made available so far regarding its pharmaco-toxicological effects. The aim of this study was to investigate the effects of the systemic administration of both the single (±)cis (0.1–60 mg/kg) and (±)trans (30 and 60 mg/kg) stereoisomers and their co-administration (e.g., (±)cis at 1, 10 or 60 mg/kg + (±)trans at 30 mg/kg) in mice. Moreover, we investigated the effect of 4,4′-DMAR on the expression of markers of oxidative/nitrosative stress (8-OHdG, iNOS, NT and NOX2), apoptosis (Smac/DIABLO and NF-κB), and heat shock proteins (HSP27, HSP70, HSP90) in the cerebral cortex. Our study demonstrated that the (±)cis stereoisomer dose-dependently induced psychomotor agitation, sweating, salivation, hyperthermia, stimulated aggression, convulsions and death. Conversely, the (±)trans stereoisomer was ineffective whilst the stereoisomers’ co-administration resulted in a worsening of the toxic (±)cis stereoisomer effects. This trend of responses was confirmed by immunohistochemical analysis on the cortex. Finally, we investigated the potentially toxic effects of stereoisomer co-administration by studying urinary excretion. The excretion study showed that the (±)trans stereoisomer reduced the metabolism of the (±)cis form and increased its amount in the urine, possibly reflecting its increased plasma levels and, therefore, the worsening of its toxicity.Peer reviewedFinal Published versio

Evaluation of Cytotoxic and Mutagenic Effects of the Synthetic Cathinones Mexedrone, α-PVP and α-PHP

Mexedrone, α-PVP and α-PHP are synthetic cathinones. They can be considered amphetamine-like substances with a stimulating effect. Actually, studies showing their impact on DNA are totally absent. Therefore, in order to fill this gap, aim of the present work was to evaluate their mutagenicity on TK6 cells. On the basis of cytotoxicity and cytostasis results, we selected the concentrations (35–100 µM) to be used in the further analysis. We used the micronucleus (MN) as indicator of genetic damage and analyzed the MNi frequency fold increase by flow cytometry. Mexedrone demonstrated its mutagenic potential contrary to the other two compounds; we then proceeded by repeating the analyzes in the presence of extrinsic metabolic activation in order to check if it was possible to totally exclude the mutagenic capacity for α-PVP and α-PHP. The results demonstrated instead the mutagenicity of their metabolites. We then evaluated reactive oxygen species (ROS) induction as a possible mechanism at the basis of the highlighted effects but the results did not show a statistically significant increase in ROS levels for any of the tested substances. Anyway, our outcomes emphasize the importance of mutagenicity evaluation for a complete assessment of the risk associated with synthetic cathinones exposure

Low-normal doses of methiopropamine induce aggressive behaviour in mice

Recreational use of illicit methiopropamine (MPA) is a public health concern because it produces neurochemical effects comparable with those induced by methamphetamine (METH). The present study investigated the effects of MPA on the expression of an aggressive behaviour. Eighty CD-1 male mice, after receiving intraperitoneal injection of saline, MPA (0.01-10 mg/kg), METH (0.01-10 mg/kg), or AMPH (0.01-10 mg/kg), once a week over a 5-week period, underwent the resident-intruder test and spontaneous locomotor activity measurement. Results showed that all psychostimulants induce aggressive behaviour even at low doses, with a dose-dependent increase and a time-dependent sensitisation. MPA potency was similar to METH and superior to AMPH. Therefore, MPA-induced aggressive behaviour may appear even at MPA dosages free of cardiovascular or other behavioural adverse effects and could become a non-intentional side effect that users experience after increasing and repeating MPA consumption

Reply to "MDPV-induced aggression in humans not established"

Reply to the the comments made by KY O’Malley and C Medina-Kirchner on the manuscript "Acute and repeated administration of MDPV increases aggressive behavior in mice: forensic implications"

Behavioral and Pharmacokinetics Studies of <i>N</i>-Methyl-2-Aminoindane (NM2AI) in Mice: An Aminoindane Briefly Used in the Illicit Drug Market

Drug forums are considered as the main platform sources that have contributed to the increase in NPS popularity, especially for those not yet known to law enforcement and therefore not yet illegal. An example is the new synthetic stimulant NM2AI, which has a very short history of human use and abuse. Little is known regarding this compound, but some information from internet forums and the scientific literature indicates NM2AI as a structural derivate of MDAI, which is known for its entactogenic activity. Indeed, the purpose of this study is to evaluate, for the first time, the in vivo acute effect induced by the intraperitoneal injection of NM2AI (1–10–30–100 mg/kg) in mice. We demonstrate the sensory (by visual placing and object tests) and physiological (core temperature measurement) function variations, nociceptor (by tail pinch test) and strength (grip test) alterations, and sensorimotor (time on rod and mobility) decrease. Moreover, we verify the mild hallucinogenic effect of NM2AI (by startle/prepulse inhibition test). Lastly, we perform a pharmacokinetic study on mice blood samples, highlighting that the main active metabolite of NM2AI is 2-aminoindane (2AI). Taken together, our data confirm the suspected entactogenic activity of NM2AI; however, these in vivo effects appear atypical and less intense with respect to those induced by the classic stimulants, in surprising analogy with what is reported by networked users

Synthetic cannabinoid JWH-073 alters both acute behavior and in vivo/vitro electrophysiological responses in mice

JWH-073 is a synthetic cannabinoid (SCB) that is illegally marketed within an "herbal blend", causing psychoactive effects more intense than those produced by Cannabis. Users report that JWH-073 causes less harmful effects than other SCBs, misrepresenting it as a "safe JWH-018 alternative", which in turn prompts its recreational use. The present study is aimed to investigate the in vivo pharmacological activity on physiological and neurobehavioral parameters in male CD-1 mice after acute 1 mg/kg JWH-073 administration. To this aim we investigate its effect on sensorimotor (visual, acoustic, and tactile), motor (spontaneous motor activity and catalepsy), and memory functions (novel object recognition; NOR) in mice coupling behavioral and EEG data. Moreover, to clarify how memory function is affected by JWH-073, we performed in vitro electrophysiological studies in hippocampal preparations using a Long-Term Potentiation (LTP) stimulation paradigm. We demonstrated that acute administration of JWH-073 transiently decreased motor activity for up to 25 min and visual sensorimotor responses for up to 105 min, with the highest effects at 25 min (similar to 48 and similar to 38%, respectively), while the memory function was altered up to 24h (similar to 33%) in treated-mice as compared to the vehicle. EEG in the somatosensory cortex showed a maximal decrease of alpha (similar to 23%) and gamma (similar to 26%) bands at 15 min, beta (similar to 26%) band at 25 min, a maximal increase of theta (similar to 14%) band at 25 min and delta (similar to 35%) band at 2 h, and a significant decrease of theta (similar to 18%), alpha (similar to 26%), and beta (similar to 10%) bands during 24 h. On the other hand, EEG in the hippocampus showed a significant decrease of all bands from 10 min to 2 h, with the maximal effect at 30 min for theta (similar to 34%) and gamma (similar to 26%) bands and 2 h for alpha (similar to 36%), beta (similar to 29%), and delta (similar to 15%) bands. Notably, the delta band significant increase both at 5 min (similar to 12%) and 24 h (similar to 19%). Moreover, in vitro results support cognitive function impairment (similar to 60% of decrease) by interfering with hippocampal synaptic transmission and LTP generation. Our results suggest that JWH-073 deeply alters brain electrical responsiveness with minor behavioral symptoms. Thus, it poses a subtle threat to consumers who mistakenly consider it safer than other SCBs

The Old and the New: Cardiovascular and Respiratory Alterations Induced by Acute JWH-018 Administration Compared to Δ⁹-THC—A Preclinical Study in Mice

Several new psychoactive substances (NPS) are responsible for intoxication involving the cardiovascular and respiratory systems. Among NPS, synthetic cannabinoids (SCs) provoked side effects in humans characterized by tachycardia, arrhythmias, hypertension, breathing difficulty, apnoea, myocardial infarction, and cardiac arrest. Therefore, the present study investigated the cardio-respiratory (MouseOx Plus; EMKA electrocardiogram (ECG) and plethysmography TUNNEL systems) and vascular (BP-2000 systems) effects induced by 1-naphthalenyl (1-pentyl-1H-indol-3-yl)-methanone (JWH-018; 0.3–3–6 mg/kg) and Δ9-tetrahydrocannabinol (Δ9-THC; 0.3–3–6 mg/kg), administered in awake CD-1 male mice. The results showed that higher doses of JWH-018 (3–6 mg/kg) induced deep and long-lasting bradycardia, alternated with bradyarrhythmia, spaced out by sudden episodes of tachyarrhythmias (6 mg/kg), and characterized by ECG electrical parameters changes, sustained bradypnea, and systolic and transient diastolic hypertension. Otherwise, Δ9-THC provoked delayed bradycardia (minor intensity tachyarrhythmias episodes) and bradypnea, also causing a transient and mild hypertensive effect at the tested dose range. These effects were prevented by both treatment with selective CB1 (AM 251, 6 mg/kg) and CB2 (AM 630, 6 mg/kg) receptor antagonists and with the mixture of the antagonists AM 251 and AM 630, even if in a different manner. Cardio-respiratory and vascular symptoms could be induced by peripheral and central CB1 and CB2 receptors stimulation, which could lead to both sympathetic and parasympathetic systems activation. These findings may represent a starting point for necessary future studies aimed at exploring the proper antidotal therapy to be used in SCs-intoxicated patient management