CXCR4 inhibition with AMD3100 attenuates amphetamine induced locomotor activity in adolescent Long Evans male rats

Adolescent psychostimulant abuse has been on the rise over the past decade. This trend has demonstrable ramifications on adolescent behavior and brain morphology, increasing risk for development of addiction during adolescence and in later adulthood. Neuroimmune substrates are implicated in the etiology of substance use disorders. To add to this body of work, the current study was developed to explore the role of a chemokine receptor, CXC Chemokine Receptor 4 (CXCR4), in the development of amphetamine (AMPH) sensitization. We targeted CXCR4 as it is implicated in developmental processes, dopaminergic transmission, neuroimmune responses, and the potentiation of psychostimulant abuse pathology. To evaluate the role of CXCR4 activity on the development of AMPH sensitization, a CXCR4 antagonist (Plerixafor; AMD3100) was administered to rats as a pretreatment variable. Specifically, adolescent Long Evans male rats (N = 37) were divided into four groups: (1) AMD3100 (IP, 4.0 mg/kg) + AMPH (IP, 4.0 mg/kg), (2) saline (SAL; 0.9% NaCl) + AMPH, (3) AMD3100 + SAL, and (4) SAL + SAL. Animals were first habituated to locomotor activity (LMA) chambers, then injected with a pretreatment drug (AMD3100 or SAL) followed by AMPH or SAL every other for four days. After a one-week withdrawal period, all animals were administered a low challenge dose of AMPH (IP, 1.0 mg/kg). AMPH-injected rats displayed significantly more locomotor activity compared to controls across all testing days. CXCR4 antagonism significantly attenuated AMPH-induced locomotor activity. On challenge day, AMD3100 pre-treated animals exhibited diminutive AMPH-induced locomotor activity compared to SAL pre-treated animals. Postmortem analyses of brain tissue revealed elevated CXCR4 protein levels in the striatum of all experimental groups. Our results implicate CXCR4 signaling in the development of AMPH sensitization and may represent an important therapeutic target for future research in psychostimulant abuse.

2D-QSAR Studies of Dopamine Transporter Inhibitors (DAT) Using OPS and GA Variable Selection Approaches

Today, drug abuse has developed into a social problem and begun to demand specific measures from different social sectors and government agencies all over the world. Despite significant efforts made toward relevant mechanistic targets, such as the dopamine transporter (DAT), the development of pharmacotherapeutic treatments of psychostimulant abuse has remained a challenge so far. Using a set of 49 2-[(diphenylmethyl)sulfanyl]ethanamines described as DAT inhibitors, 2D-QSAR/PLS studies were performed using two different approaches of variable selection: Ordered predictors selection (OPS) and genetic algorithm (GA). All structures were optimized at the B3LYP/6-311G++(d,p) level of theory. The molecular descriptors were obtained in the Dragon 6 program (topological, geometric, molecular, and constitutional) and GaussView 03 (electronic). Both models were formed by two latent variables. Model 1 (OPS) was constructed with four molecular descriptors (GATS3m, Mor15p, SpMin3_Bh(s), and HOMO-1), while six (Mor13m, CATS2D_09_LL, RDF110u, RDF085m, Mor24s, and RDF010s) were required to obtain model 2 (GA). The models can be considered reasonably different: In model 1, electronic features predominate, whereas in model 2, steric and geometric effects do. The overall test indicated that models 1 and 2 have equivalent predictive ability (Average r2m Overall = 0.730 versus 0.710 and Delta r2m Overall = 0.122 versus 0.151). However, model 1 is simpler (it has only four descriptors, which facilitates its interpretation), presents more relevant information used in the construction of its two latent variables (75.99% versus 64.07%), and its calibration is more significant than that of model 2 (Fn,n−p−1 = 115.814 versus 80.888, for the same tabled F value, where n = 36, and n − p − 1 = 3.256, with alfa = 0.05). Considering these results, although model 2 may also be considered a good result, model 1, obtained using the OPS approach for variable selection, may be considered more reliable for prediction purposes. This result is in agreement with good results previously obtained using the OPS methodology.

Excited delirium syndrome from psychostimulant abuse can mimic a violent scene of death

Background Previous reported cases on excited delirium syndrome studied on the common clinical manifestations of the syndrome. The usual forensics implication for the syndrome is that death commonly is associated with restraint procedures by law enforcement agencies; however, not many cases reported highlights the difficulties in attributing a violent scene of death to the syndrome. Case presentation We present a case of a partially naked body found in an apartment unit under suspicious circumstances with multiple injuries. The scene of death was violent, and the body was found with blood wiped all over the floor and walls. Investigators believed a violent crime had occurred, and a suspect was reprimanded. However, upon autopsy, it was found that all injuries were superficially inflicted and were unlikely to have been part of an act of commission or caused his death. Internal examination found no remarkable pathology. Toxicology revealed a presence of psychostimulants, that is, methamphetamine, MDMA, and ethyl alcohol. Reconstruction of events by the witness, who was initially suspected of the ‘murder’, revealed that the injuries and his death could likely be explained by an episode of excited delirium. Conclusion The case highlights the challenges faced when attributing excited delirium syndrome as a cause of death. The syndrome can present with injuries from aggressive or bizarre behaviour, coupled with the destruction of property, which may confuse investigators on the possible manner of death.

Cannabidiol Treatment Might Promote Resilience to Cocaine and Methamphetamine Use Disorders: A Review of Possible Mechanisms

Currently, there are no approved pharmacotherapies for addiction to cocaine and other psychostimulant drugs. Several studies have proposed that cannabidiol (CBD) could be a promising treatment for substance use disorders. In the present work, the authors describe the scarce preclinical and human research about the actions of CBD on the effects of stimulant drugs, mainly cocaine and methamphetamine (METH). Additionally, the possible mechanisms underlying the therapeutic potential of CBD on stimulant use disorders are reviewed. CBD has reversed toxicity and seizures induced by cocaine, behavioural sensitization induced by amphetamines, motivation to self-administer cocaine and METH, context- and stress-induced reinstatement of cocaine and priming-induced reinstatement of METH seeking behaviours. CBD also potentiated the extinction of cocaine- and amphetamine-induced conditioned place preference (CPP), impaired the reconsolidation of cocaine CPP and prevented priming-induced reinstatement of METH CPP. Observational studies suggest that CBD may reduce problems related with crack-cocaine addiction, such as withdrawal symptoms, craving, impulsivity and paranoia (Fischer et al., 2015). The potential mechanisms involved in the protective effects of CBD on addiction to psychostimulant drugs include the prevention of drug-induced neuroadaptations (neurotransmitter and intracellular signalling pathways changes), the erasure of aberrant drug-memories, the reversion of cognitive deficits induced by psychostimulant drugs and the alleviation of mental disorders comorbid with psychostimulant abuse. Further, preclinical studies and future clinical trials are necessary to fully evaluate the potential of CBD as an intervention for cocaine and methamphetamine addictive disorders.

Making the Case for ‘Power Abuse Disorder' as a Nosologic Entity

The development of societies and cultures arguably is based on the ability of human primates to form hierarchies in which some individuals acquire and wield power, that is, control resources and influence and control the behavior of their conspecifics. In the following, we focus on the type of human primate power wielding that (a) harms and (b) produces excessive negative emotions in (1) the victim(s) of the power wielder and (2) the power wielder her/himself. If such a harmful behavior of the power wielder is not accompanied by an ethically justifiable benefit for the involved human primate groups, it can be considered “power abuse.” We propose to term the associated behaviors, cognitions, and emotions of the power wielder as “power abuse disorder” (PAD). This behavior results from what we consider addictive behavior of the power abuse disordered (PADed) power wielder. PAD can be diagnosed on the basis of the World Health Organization's criteria for “dependence syndrome” as listed in the International Classification of Diseases version 10. We will demonstrate that many PADed individuals may very likely carry the Zeitgeist diagnosis “burnout.” This article reviews the current understanding of the neural correlates of PAD and suggests future research. Based on the available evidence, PAD seems to be associated with a dysfunction of the mesocorticolimbic dopamine system, rendering PADed individuals vulnerable for psychostimulant abuse/dependence, and suggesting specific pharmacotherapeutic approaches to treat PAD.